Unit I Introduction In the early days when there were standalone systems, to transfer data to various places was considered very difficult. There were different computers for various jobs, like information gathering, processing, or distributing. Due to rapid technological progress these areas are rapidly converging and differences between them are rapidly disappearing. Though the computer industry is new but the progress, which it has made in its life span, is remarkable, especially in the field of telecommunications. Initially, centralized systems were being used but as more and more stations requirements arise to participate in the data exchange, there developed the arena of computer networks. The computer network includes a single computer serving all the computational requirements, which arose from various interconnected autonomous computers. The two computers are said to be interconnected if they are able to exchange information and if one computer can control the functioning (start/stop) then such computers are not autonomous. Sometimes the subject of computer network is related with distributed system however they are not so as in the distributed system the existence of multiple autonomous computers is transparent to user, i.e. user of such environment is unaware of multiple processors available in the system. Secondly, in a network user has to explicitly log onto machine, submit various jobs remotely, etc personally while in the distributed system nothing is being done explicitly, its done automatically by the system without even user knowing it. One can say that a distributed system is a software system, which is implemented on top of network and provides high degree of cohesiveness and transparency. Thus the main distinction within two lies with the software rather than the hardware. Data Communication Networking It basically means that with the help of networks the computer data is transported between various stations on the network. Data communications takes place between devices that are directly connected by a variation of point—topoint transmission medium. But for devices placed far apart and also during requirement of various devices that they need to be connected to many others at various times, point-to-point connections become impractical. Hence this problem is being resolved by the use of networks. Nodes wanting to participate in the data transmission attach themselves to the network. Why Computer Network’s Interconnection of various autonomous computers for the purpose of data exchange is called as computer network and is popular and spreading day by day because human needs are growing and he wants that everything should be available to him at its doorsteps. Because of its features like cost reduction, resource sharing, reliability, cooperativeness computer networks today had become a need without which life seems to be very difficult, whether be it the area of electronic message transfer, online banking, shopping, etc. Uses of Computer Networks Today computer networks are being used in offices, companies, home to extract the features being provided by it. Networks for Companies and Offices As medium and large scale companies have many offices far apart within a city or so, there arise the need of interconnecting computers placed at different sites as at many times there is a need to monitor activities going at

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different places, etc. Now as these various sites departments have lot of data, keeping complete replica of data at various places also leads to increase in cost, attaching these computers in a network reduces this problem. Due to the resource-sharing feature of network, data is available to everyone without regard to its physical location. Also networks offer high degree of reliability by having alternative sources of supply. Example is the case of placing backup or secondary servers, which are exact replica of the primaries. Utilising networks in an organization saves money as, using network reduces both hardware and software cost. Small computers with proper interconnections can remove mainframes from picture. The concept of file servers and print servers enables remote file access and print requests. Network for People Today computer network is helping people in paying their bills, managing their bank accounts, handling their investments without actually going to that place and wasting time. Home shopping is also becoming popular as by just sitting at home one can place an order for books, various products, booking tickets, etc , this had created interest in housewives too. Another application which falls under this category is accessing information on the Web (WWW) i.e. World Wide Web which is a web of information, any information related to arts, buildings, health, education, and lot more is available at every hour. All of these require interactions between a person and a remote database. Demands of applications like email, videoconferencing (virtual meetings) are growing day by day. In short, ability to merge information, communication and entertainment will definitely give rise to new industry based on computer networking. Network Types As network is a collection of interconnected components or devices, but question arises how networks are classified and what are the factors, which contributes towards this factor. To meet needs of various applications, computer networks are available with different interconnection layouts and plans, method of access, protocols and media. On the basis of coverage of geographical area, networks can be classified as: -

Local Area Network (LAN)

-

Metropolitan Area Network (MAN)

-

Wide Area Network (WAN)

MEDIA Categories of Transmission Media: Transmission media is a path through which signal is propagated. The data signal is transmitted in the form of EM signals (Electromagnetic waves), and the properties of signals which also plays a role in the quality of signal transmission ,like sound waves never pass glass while light waves does. Hence depending on the path given to EM

2

signal, the transmission media can be categorised as: -

Guided Media

-

Unguided Media

Guided Media If the electromagnetic waves are guided through a physical path then that transmission is called as guided transmission and that physical path is called guided media, e.g Twisted wire pair, Co-axial cable, Optical fiber. In guided transmission, it’s the fabrication of media, which ultimately effects the data transmission. More secure the media is, high data rates it can support. Unguided Media If The same electromagnetic signal is released through open air, space, water then the transmission is said to be wireless or unguided and the media is known as unguided /wireless media. So, here the atmospheric conditions will effect the transmission .e.g microwaves, radiowaves, infrared rays Twisted Wire Pair It is the most cheapest guided transmission media. Physical Description This cable consists of two independently insulated wires twisted around one another. A single wire pair is one communication link Twisted-pair cable (shown in Figure 30) is used by older telephone networks and is the least expensive type of localArea network (LAN) cable, most networks contain some twisted-pair cabling at some point along the network too. The twists are being laid to reduce the crosstalk interference between adjacent pairs in the cable. On long- distance links, the twist length varies from 2 to 6 inches. The wires have thickness within the range of 0.016 to 0.036 inches. These cables are generally installed within a building when built, hence cheaper to use them for data transmission as no extra cost of laying a separate cable in incurred. This cable is capable of carrying both analog and digital signal.

Figure Copper Wires Applications As it can carry both analog and digital signals ,hence it is most common media for voice communication(analog signal) as well as for the communications of various networks within buildings nearby( digital signal). Transmission Characteristics Thus, the advantages of this media can be summarised as: 1.

As it is the oldest media hence is easily available and is cheaper too.

2.

The media can be used for both, analog and digital signals.

3.

It is the least expensive media for shorter distances.

The disadvantages are: 1.

Not secure and not immune to EMI.

2.

Due to thin size, easy to break , hence difficult to maintain.

Various categories of twisted wire pair available are:

3

Unshielded and Shielded Twisted Pair UTP(Unshielded Twisted wire pair is that cable which has no protective sheath to prevent the signal being entered into interference. These are generally seen in telephone cables and local area networks. They can further be categorised into Category 3 ,Category 4, Category 5 cables. If proper insulation is being provided to the available unshielded pairs they offer more security and bandwidth, and are called shielded twisted wire pair(STP) cables. Baseband transmissions are those where the entire bandwidth of the cable is being utilised for a single channel . The original band of frequencies of a signal before it is modulated for transmission at higher frequency, the signal is multiplexed and sent on a carrier with the other signals at the same time. While, Broadband transmission is basically a frequency division multiplexed situation(discussed later), where the bandwidth of the media is separated into subchannels of either equal or varying frequency ranges, which itself can be treated as separated transmission. A type of data transmission in which a single medium (wire) can carry several channels at once. Cable TV, for example, uses broadband transmission. In contrast, base band transmission allows only one signal at a time. Most communication between computers, including the majority of local area networks, use base band communications. An exception is BISDN networks, which employ broadband transmission. Coaxial Cable A coaxial cable consists of a centre stiff copper wire surrounded by an insulation, the insulation is encased by a cylindrical shield of braided wire. Then the outer conductor is covered in a protective plastic sheath. The signal is transmitted by the inner copper wire and is electrically shielded by the outer metal sleeve. A single coaxial cable (Figure 32) has a diameter of 0.4 to about 1 inch. The shield minimizes electrical and radio frequency interference. Because of the shielded construction ,this cable is less susceptible to interference and crosstalk than twisted wire pair. It can be used for longer distances as well and due to its high bandwidth than twisted wire pair supports more stations on multipoint link. Outer conductor

outer sheath

insulation Inner conductor Coaxial cable is a most versatile transmission medium and its applications covers areas like, television transmission, LANs, telephone system, etc. The most common of it has been the cable tv which everybody is receiving at their home is through this cable only. Using FDM (frequency division multiplexing) this cable can carry 10,000 voice channels simultaneously. In networks, this cable can support wide range of devices, traffics, over varying distances but it is difficult to connect to network devices using this cable rather than twisted pair. Many coaxial systems requires the connectors on the main cable to be attached directly to the adapter on the PCs, hence reduces the flexibility of locating workstations and servers. Coaxial cabling is the primary type of cabling used by the cable television industry and is also widely used for computer networks. Although more expensive than standard telephone wire, it is much less susceptible to interference and can carry much more data. Because the cable television industry has already connected millions of homes with

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coaxial cable, many analysts believe that they are the best positioned to capitalize on the much-heralded information highway. A coaxial cable can carry both analog and digital signals. As it can be seen from Figure 31, that the frequency characteristics of this cable are superior to twisted wire pair, so can be efficiently used at higher frequencies and data rates. As the construction is more insulated, it is less susceptible towards cross-talking and interference than twisted pair. It has been seen that higher frequencies produce a current flow on the outer portion of the wire leading to “skin effect” which creates a level of attenuation and crosstalk, this was a problem seen on un-insulated wires but coaxial cable also goes through this effect. Generally it is used for broadband transmissions. Two kinds of coaxial cables are widely used. One is 50-ohm while other is 75-ohm. The former is used for digital transmission and is seen in local networks while the latter is commonly used for analog transmission in cable TVs. Comparison Of Wire-pair cable and Coaxial Cable 1.

Coaxial cable supports large number of channels per cable than twisted wire pair.

2.

Coaxial cables are less susceptible to interference and crosstalk than twisted wire pair.

3.

In coaxial cables there is less delay distortion and also less variation of amplitude with frequency than in twisted pairs.

4.

Due to high propagation speeds, there is no requirement for echo suppressors over large distances, as the interval between the speech and its echo becomes very small, hence neglected.

5.

It supports high bandwidth than twisted pair and hence high data rates.

Optical Fibre

Figure Optical Fiber Physical Description The technology uses glass (or plastic) threads (fibres) to transmit the data through it. A fibre optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages converted onto light waves. An optical fibre is thin(2 to 125 micrometre), flexible medium. Ultrapure fibre is difficult to manufacture , hence the material is doped with certain impurities. It is cylindrical in shape and consists of three concentric sections, i.e core, cladding and the jacket at the outermost .

Cladding

Core Jacket Figure Optical Fibre

5

The core is different from cladding in varying refractive indexes. The core has high refractive index than cladding and the main purpose of these two is to hold the light ray within the core, any unwanted rays are absorbed into the jacket. The core is the inner core of the optical fibre and consists of very thin strands or fibres which are made up of fused silica or glass or plastic. Each optical fibre is surrounded by the cladding which differ from core in the optical properties. Finally, it is surrounded by the jacket which prevents the cable from moisture, crushing and other environmental hazards. Due to its construction, the optical fiber is difficult to tap and hence is more secure. Applications These are widely used for long distance communications and supports better data rate than the coaxial cable and twisted pair. This media is more secure and is immune to EMI(electromagnetic interference). Some of the features which are making it popular are: Greater Capacity: It can support data rates up to 2Gbps over few tens of kilometres as compared to 10-100 Mbps of other two for few kilometres. Smaller size and light weight, Lower attenuation, No EMI, Greater repeater spacing. An optical fibre is generally used for long haul trunks, metropolitan trunks, rural exchanges, subscriber loops and local area networks for high data rates. The long haul trunks cover distance of 00 miles with a support of 20,000 to 60,000 voice channels. The metropolitan trunks covers a span of up to 7.8 miles with 100,000 voice channels and, The rural exchange supports area of 25 to 100 miles with 5,000 voice channels and in LANs , the optical fibres can give data rate of up to 100Mbps. The characteristics of all the cables(twisted pair, Co-axial cable, optical fibre ) for point to point transmission can be summarised as: Transmission Medium Data rate Twisted Pair

Bandwidth

Repeater spacing

4 Mbps

3 Mhz

2 to 10 km

Co-axial Cable

500 Mbps

350 Mhz

1 to 10 km

Optical Fibre

2 Gbps

2 Ghz

10 to 100 km

Transmission Characteristics Optical fibres operate in the range of 1014 to 1015 Hz which covers portion of visible rays in the electromagnetic spectrum. Light travels in the media with the principle of “total internal reflection”. At each core-cladding interface, part of energy is being absorbed which ultimately leads to loss of strength of signal. The repeaters used midway works on same principle and are different from repeaters used for other medias. While joining two fibres two cover large distances, alignment care should be taken as if both are not properly aligned, i.e the central axis of first fibre is not inline with the other then different misalignments can exist which can lead to loss of signal. cladding incident ray light ray coming out of core jacket

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Figure Light Ray Propagation In Optical Fibre In an optical transmission system the transmitter is the LED/ILD(light emitting diode/injection laser diode) which works on the principle that when voltage pulse is applied to them they generate light pulse for that corresponding voltage pulses, hence the presence and absence of voltage pulse leads to the presence and absence of light pulse. Then this light pulse is injected into the cable where after suffering repeatedly reflection it propagates. At the receiver there are light detectors which perform the reverse action that is, when light pulse falls on them they convert it to voltage pulse. In an optical transmission system it should be seen that the led, fibre and detectors should align along the central axis ,in order to receive the whole light /voltage pulse. The type of emitting diodes can be : Edge emitting: are those which emit light from an edge of the diode on application of voltage pulse, used for single mode fibres. Surface emitting: are those diodes which emit light pulses from whole surface when voltage is applied to them. These are generally used for multimode fibres. Optical fibres have a bright future because of following reasons: 1.

Optical transmission has a very large bandwidth and hence supports high data rates.

2.

Optical fibres have carriers in the form of photons rather than electrons in metallic conductors and as photons have no charge, so are not effected by the electric and magnetic field, so such fibres are immune to the electro magnetic interference.

3.

Optical fibres offers less attenuation to the signals passing across them, hence repeater spacing can be more.

4.

Optical fibres offer secure transmission. Transmission of light does not yield residual intelligence around the cable while residual electromagnetic energy is found around the metallic cables carrying electrical transmission. Moreover these cables are difficult to tap due to its construction and properties.

5.

Optical fibre cables are very light in weight and small too hence can be drawn to in high buildings.

6.

Optical fibres are easy to install, maintain and operate at every temperature.

7. As signal loss is very less, the error rate is also very less. For example, a typical error rate on an optical fibre is 10 9

8.

versus 10-6 in metallic conductors.

Due to reduce in cost of VLSI, the semiconductor devices are becoming cheaper which are used at both ends of the optical system, i.e diode and detector. This reduction in cost has helped in increasing popularity of these fibres.

9.

Data can be transmitted digitally (the natural form for computer data) rather than analogically.

10. Fibre optics is a becoming popular technology for local-area networks. In addition, telephone companies are steadily replacing traditional telephone lines with fiber optic cables. In the future, almost all communications will employ fiber optics. Wireless Media The electromagnetic spectrum can be described as, to which various EM waves belong

7

F(Hz) 104 106 VLF

108

1010

1012

1014

Radio Microwave Infrared Figure Electromagnetic Spectrum

1016

1022

Visible

1024 UV

X-ray

Gamma ray

As discussed earlier, these media are not physical in nature, these comprises of: Radio Wave Radio

waves are easy to generate and can travel long distances. These rays can pass the obstacles like buildings

coming in their way of transmission. Due to their low frequency property, they are omni directional i.e they can travel in all directions from source hence source and receiver need not be carefully aligned. The properties of radio waves are dependent on frequency, i.e at low frequencies, these pass through obstacles but the strength of it falls of rapidly with the distance from the source. Simultaneously at high frequencies, radio waves tend to travel in straight lines and in doing so, they bounce off obstacles. They are strongly effected during rainy season, as that time they are absorbed more. At all frequencies, radio waves suffers interference from motors and other electrical devices. Due to radio’s ability to travel long distances, interference between users is a problem, hence various radio transmission have to obtain a license from government. In VLF,LF,MF bands, radio waves follow the ground and are effected by the curvature of the earth. The disadvantage is that they offer low bandwidth. In HF and VHF, the ground waves are absorbed by earth but the waves which reach the ionosphere, (where charged particles are present, this layer exists at the height of 100 to 500 km) they are then refracted by this layer and are sent back to the earth. At various atmospheric conditions these waves may undergo several bouncing. Broadcast Radio This

transmission does not require the use of the antennas as it is broadcast in nature. These comprises of

frequencies between 3khz and 300 Ghz. The range of 30Mhz to 1Ghz is useful for broadcast communication, here ionosphere is transparent. Transmission is limited to line of sight hence distant transmitters won’t interfere with each other due to the reflection from the atmosphere. This transmission is less effected by rainfall. This transmission is strongly effected by the multipath interference ,i.e the reflection from the land, water, etc objects creates multiple paths between antennas, the effect is generally seen when multiple images are being seen on the TV reception when any airplane passes by. Infrared In this transmission the line of sight transmission is needed i.e receiver must be visible from the sender. These radiations can’t pass through buildings hence security and interference problems are minimized. Also there is no authority which permits to use these radiations for transmission. Microwave The wireless transmission and reception is being done with the help of antennas. These antennas radiates/picks up electromagnetic energy depending on when its transmitting and when receiving. The wireless transmission can be omni directional or directional depending on that the signal is being transmitted/received in all the direction or single direction. High frequencies permit directional transmission as they are easily to focus while low frequency beams offer omni directional transmission .The frequencies in the range of 2Ghz to 40Ghz are termed as microwave frequencies .At

8

this range directional beams are possible and such waves are also possible for point to point transmission using satellites.

Satellite Communication Communications Satellites have been around since 1958. A communications satellite is a spacecraft that orbits the Earth and relays messages, radio, telephone and television signals. Stations on the ground, called earth stations, transmit signals to the satellite, which then relays the signal to other earth stations. As a newer form of communications, communications satellites are very useful in bringing the people in the world together. With the help of satellites communications became faster. The first satellite to relay messages from one Earth Station to another was SCORE (Signal Communicating by Orbiting Relay Equipment) launched on December 18, 1958. These early satellites, because they were visible from both sides of the Atlantic Ocean simultaneous for only a short time could provide only a period of five hours a day for communications. Satellite is nothing but a repeater in a sky. It has various transponders (antennas) placed on its body which operates with solar cells, charged with the help of solar radiations. As microwaves point-to point transmission requires line of sight transmission, hence satellites are launched in geo-stationary orbit. Its that orbit which has same period of rotation as that of earth, hence satellite appear to be stationary with respect to a point on the earth. As this orbit is 22,300 miles above from the earth, hence rockets are used to launch them onto sky. Communications through satellites are either passive or active. The first communications satellites were passive. Signals from Earth were merely reflected from the orbiting metallic sphere. Later types of satellites are active. Active communication satellites receive signals from Earth, electronically strengthen the signals, and then transmit the signals to Earth. This relaying of signals from one Earth Station to another is done through the satellite's transponder. Most communications satellites have more than one transponder and antenna so that they can relay several users of radio waves or signals at the same time. Satellite communication has a significant propagation delay of 270ms,and total of three satellites can cover 90% of earth’s surface, rest can be assumed as land covering with water. These three satellites are at 120 0 spacing to each other. There are various satellite communication bands with varying bandwidths. Higher, the bandwidth more directional beams exists leading to less angular spacing between the satellites in same band. The uplink (signal going towards satellite) and downlink (signal relayed from satellite) are separated on the basis of frequency to minimize interference .A single satellite with the help of polarizations can relay two signals of same frequency in same direction. Some of the bands available for satellite communication are 11/12/14 Ghz (Ku band), 6/4Ghz (C band), 30/20 Ghz (K band). Some of the unique aspects of communication satellites are : 1.

The technology offers large communication capacity.

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2.

Satellites are inherently broadcast in nature so at low cost can relay the transmission to a very large span.

3.

The transmission cost here is independent of the distance between two earth stations.

4.

There is significant propagation delay due to large distance between satellite and the earth station.

5.

This transmission because of different uplink and downlink frequency can receive its own transmission at same time.

6.

Due to its broadcast nature its difficult to provide security, hence transmissions are generally made encrypted.

Types of Communication/Transmission Depending on how the data is transferred, data transmission can belong any of the category: -

Synchronous Transmission

-

Asynchronous Transmission

Synchronous Transmission When data is being send at periodic intervals with constant arrival rate then data is said to be synchronised. Here, each data block is being surrounded by control bits called flags which delimits the data block boundaries and helps the receiver in notifying the arrival of data. So, here a separate clock or the clocking codes are being used because a drift in clock frequency can lead to loss of data. So, the timing signal provides a mean to synchronise the clocking devices at the sending and receiving side. Once, the devices are synchronised they are generally stable.The flag/preamble must be distinguished from user data to allow the receiver to search for the incoming data signal.

Flag

Userdata

Flag

Figure Synchronous data frame Asynchronous Transmission When a data character is sent at any time,i.e no fixed interval this can lead to loss of synchronisation as it is then difficult to know that when next character is arriving, hence in this approach each character is being preceded by a bit called start bit while succeeded by a stop bit. The arrival of these bits will tell the receiver about the corresponding character. This type of communication is generally found in machines or terminals such as teletypes or teleprinters and low speed computer terminals. It is very simple to implement. In this approach too the clock timings of sampling should be maintained as fast and slow sampling can lead to problems, it might be that at one time , one bit is sampled more than once while at other time one bit is missed for being sampled, leading to wrong representation of data.

A

B

C 10

Figure Asynchronous Transmission In the above figure the varying line lengths show that the arrival time of various characters is not fixed .Generally in these systems, the start bit is placed as 0 and stop bit is 1 because when no data transmission is taking place the line is idle(voltage corresponding to 1),hence the arrival of start bit (0) is easily being sensed by the receiver with next equal bit periods for the character and finally the stop bit again bring line to idle state, thus synchronization is being achieved. The problem with this transmission is that if two characters are being transmitted with no idle time in between, then it may happen that the start bit of a character is lost then the next zero bit is considered as the start bit leading to the drift in bits, as a result of which the characters can be wrongly represented. It has been observed that the synchronous transmission is more efficient than asynchronous. Various Communication Channel Modes: There are basically three data transmission modes, these are: -

Simplex

-

Half-duplex

-

Full-duplex

Simplex In this communication mode the data flows in only one direction i,e sender always remain a sender and receiver always remain a receiver, in all it is a one way communication. So, receiver can’t intimate the sender that data was being received properly or not. In this mode, the main transmitter broadcasts a signal but it does not expects any reply from the receivers. Hence, simplex circuits are rarely used because a return path is needed to send back acknowledgement, control or error signals. Example Television and Radio broadcast. Data Flow

Transmitter

Receiver

Figure Simplex Transmission Half-duplex In this mode, the data flows in both direction but not simultaneously, i.e sender can send data to receiver and receiver can send acknowledgement as well but not together as line is common. Hence it is a two way alternate communication. This type of communication requires a wire pair and is most common for voice communication because at a time person either listens or speaks. It is also being seen in terminal to computer communication, data movement to and from hard disk. It has a disadvantage as time is needed to change over the mode, one has to move from listener mode to sender mode and this change over time might be many bits long leading to degradation in the performance. Example, rail road track, Walkie-Talkie,etc

Transmitter & Receiver

Receiver & Transmitter

11

Figure Half Duplex Transmission Full-Duplex To overcome the limitation of the half-duplex, i.e to reduce the turned around time, here different paths are being allocated because of which two way simultaneous communication can take place here. It require two wire pair, one dedicated to each party. So, here both stations can transmit and receive independently. The use of full-duplex mode leads to increase in efficiency as line turned around time here is eliminated. Example, strong arguments between two people, computer network communication, telephone channel ,etc

Transmitter & Receiver

Receiver & Transmitter

Figure Full Duplex Transmission Data Transmission Speed A term used to describe the data handling capacity of a communications system is Bandwidth. Bandwidth is the range of frequencies that is available for the transmission of data. The communication data transfer rate is measured in unit called Baud. Baud is identical to bits per second. Depending on their transmission speeds, communication channels are grouped into three basic categories

1.

Narrowband : they range in speed from 45 to 300 baud. They are used for handling low data volumes and are adequate for low speed devices. They are used mainly for telegraph lines and low speed terminals.

2.

Voiceband : they handle moderate data volumes and can transmit data at speeds up to 9600 baud. Their application is for ordinary telephone voice communication. Most remote terminals are connected to computers through voice band channels.

3.

Broadband : they are used when large volumes of data is to be transmitted at high speed. These systems provide data transmission rates of 1 million baud or more. These are used for high speed computer to computer communication or for simultaneous transmission of data to several different devices.

Topology Refers to the way in which the network of computers is connected. Each topology is suited to specific tasks and has its own advantages and disadvantages. The choice of topology is dependent upon:

•

type and number of equipment being used

•

planned applications and rate of data transfers

•

required response times

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•

cost

There are 4 major competing topologies: Bus, Ring, Star, and FDDI. Most networking software support all topology's. Bus Topology All workstations connect to the same cable segment commonly used for implementing Ethernet at 10 mbps the cable is terminated at each end wiring is normally done point to point a faulty cable or workstation will take the entire LAN down two wire, generally coax. The bus cable carries the transmitted message along the cable. As the message arrives at each workstation, the workstation computer checks the destination address contained in the message to see if it matches it's own. If the address does not match, the workstation does nothing more. If the workstation address match's that contained in the message, the workstation processes the message. The message is transmitted along the cable and is visible to all computers connected to that cable.

The above diagram shows a number of computers connected to a Bus cable, in this case, implemented as Thin Ethernet. Each computer has a network card installed, which directly attaches to the network bus cable via a T-Connector. In bus systems, all stations have access to the same cable medium. It is therefore possible that a station may already be transmitting when another station wants to transmit. Rule 1: is that a station must listen to determine if another station is transmitting before initiating a transmission. If the network is busy, then the station must back off and wait a random interval before trying again. Rule 2: is that a station, which is transmitting, must monitor the network to see if another station has begun transmission. This is a collision, and if this occurs, both stations must back off and retry after a random time interval. As it takes a finite time for signals to travel down the cable, it is possible for more than one station to think that the network is free and both grab it at the same time. Bus Network Topology Summary

Advantages

Disadvantages

Easy to implement

Limits

on

cable

length

13

and

Workstation numbers Difficult Low Cost

A

cable

As

the

to fault number

affects of

isolate all

workstations

workstations

increase,

the speed of the network slows down Star Topology All wiring is done from a central point (the server or hub) has the highest cable lengths of any topology generally STP or UTP, four wire. It is becoming common to use 10BaseT (UTP) for implementing Ethernet LANS. Each workstation is wired in star fashion back to a concentrator-wiring centre (hub). The hub is a multi-port device supporting up to about 32 ports. One of these ports is connected to a server, or the output of the hub can be connected to other hubs.

Star Topology: Summary

Advantages

Disadvantages

Easy to add new workstations Centralized control Centralized

Hub failure cripples all workstations connected to that hub Hubs are slightly more expensive than thin-Ethernet

network/hub

monitoring Ring Topology Properties:

•

Workstations connect to the ring

•

Faulty workstations can be bypassed

•

More cabling required than BUS

•

The connectors used tend to cause a lot of problems

•

Commonly used to implement token ring at 4 and 16 MBps four wire

14

Physical Implementation of A Ring Network Each workstation is connected back to a Multiple Access Unit (MAU), which supports up to eight workstations. Additional MAU are cascaded to provide greater workstation numbers. Wiring is performed in a physical star fashion, with cables wired directly from each workstation back to the MAU. Token Ring This protocol is widely used in ring networks for controlling station access to the ring. A short message (called a token) is circulated around the ring, being passed from station to station (it originates from a controller or master station, which inserts it onto the ring). A station which wants to transmit waits for the token to arrive. When it arrives, it changes it from a token to a connector message, and appends its message on the end. This is then placed on the outgoing side of the ring. Each station passes on received tokens if they have nothing to transmit. They monitor connector messages to see if the message is addressed to them. If connector messages are addressed to them, they copy the message, modify it to signify its receipt, then send it on around the ring. Connector messages, which are not addressed, to them are passed directly onto the next station in the ring. When the connector message travels full circle and arrives at the original sending station, it checks the message to see if its been received. It then discards the message and replaces it with a token. Assume that A wishes to transmit data to C: 1.

A waits for receipt of control token from its previous neighbour on the ring, D

2.

A transmits frame onto ring, B retransmits it to C, C copies frame into buffer, then sends frame back on ring with acknowledge bit set.

3.

Either A waits for start of frame, but does not repeat it thereby removing it. Or when the last bit of the frame has been received by A, it generates and passes on the token; it then processes the response bits at the tail of the frame.

4.

When the last bit of the frame has been transmitted by A, it passes on the token early-release. Ring Topology: Summary

Advantages Cable failures affect limited users Equal access for all users

Disadvantages Costly Wiring Difficult Connections

15

Each

workstation

has

full

access

Expensive Adaptor Cards

speed to the ring As workstation numbers increase performance diminishes slightly Hybrid Topology Different networks have their own advantages and limitations hence in reality a pure star or ring is seldom used. Instead, organization will use the combination of network depending on their need and structure called as hybrid arrangement.

Multipoint Topology There is yet another method of linking computers together in a network. In this method a single transmission media is shared by all nodes when a particular computer wants to send a message to another computer, it appends the destination address to the message and checks whether the communication line if free. As soon as the line if free, it broadcasts the message on the line. The message is picked up by the destined computer, which sends a acknowledgement. This method is called as broadcasting network also Advantage 1.

Reduction in physical lines

2.

Addition of new computers is easy

Local Area Network (LAN)

•

A Local Area Network (LAN) may be defined as a collection of hosts connected by a high-speed network typically within close physical proximity to one another (maximum span of 10km).

•

LANs are distinguished from other kinds of networks basically by three characteristics, via size, transmission technology and topology. The transmission technology generally used in LANs involves a single cable to which all the machines are attached.

•

This network is relatively smaller and is privately owned.

•

Hosts on a LAN all typically speak the same Protocol (language).

•

There are many LAN standards recommended by IEEE called 802.x

•

LANs run at speeds of 10 to 100 Mbps and have low delays, and low error rate.

•

Various topologies are possible for LAN, like star, ring, and bus.

•

Hosts on a LAN can speak more than one protocol.

16

Example: In a building A, the PCs speak the IPX/SPX protocol for Netware file and printing services and also speak TCP/IP for Internet services (Telnet, FTP, Mosaic, etc.)

•

On Ethernet networks anything "said" by a host can be heard by all of the other hosts on the LAN.

Thus, Computer networks that span a relatively small area and are privately owned are known as LAN. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. Most LANs connect workstations and personal computers. Each node (individual computer) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, like laser printers, as well as data. There are many different types of LANs Ethernets being the most common for PCs. Metropolitan Area Network (MAN) MAN may be defined as a network, which is defined for a span less than 50km and provides regional connectivity within a campus or small geographical area. It can be a single network like cable television or can be an interconnection of various LANs, example a company uses MAN to connect to the LANs in all of its offices within a city. A MAN is a relatively new class of network, it serves a role similar to an ISP, but for corporate users with large LANs. There are three important features which discriminate MANs from LANs or WANs: 1.

The network size falls intermediate between LAN and WAN. A MAN typically covers an area of between 5 and 50 km diameter. Many MANs cover an area the size of a city, although in some cases MANs may be as small as a group of buildings or as large as the North of Scotland.

2.

A MAN (like aWAN) is not generally owned by a single organisation. The MAN, its communications links and equipment are generally owned by either a consortium of users or by a single network provider who sells the service to the users. This level of service provided to each user must therefore be negotiated with the MAN operator, and some performance guarantees are normally specified.

3.

A MAN often acts as a high speed network to allow sharing of regional resources (similar to a largeLAN). It is also frequently used to provide a shared connection to other networks using a link to aWAN.

A typical use of MANs to provide shared access to a wide area network is shown in the figure below:

17

Use of MANs to provide regional networks, which share the cost of access to a WAN Wide Area Networks (WAN) and Internetworks

•

A Wide Area Network (WAN) or internetwork can be used to connect several LANs together and spans a large geographical area, generally a country or continent, i.e. it provides no limit of distance.

•

In WANs, the subnet consists of two distinct components, which are transmission channels and routers.

•

A WAN which is wholly owned by a single company is known as enterprise network.

•

Routers attached to each LAN filter the network traffic to and from the WAN (Figure 3).

•

Each LAN can also be separated by special modems and dedicated “Leased Lines”

•

WAN have channels which have low capacity but are relatively more error prone.

Thus, a WAN may be defined as that network which covers a large geographical area, generally a country or a continent. These are built to provide communication solutions for organizations or people who need to exchange digital information between two distant places. Since the distance is long, the local telecommunication company is involved; in fact, WANs are usually maintained by the country's public telecommunication companies (PTT's - like AT&T, Sprint, BEZEQ),

which

offer

different

communication

services

to

the

population.

The main purpose of a WAN is to provide reliable, fast and safe communication between two or more places (Nodes) with low delays and at low prices. WANs enable an organization to have one integral network between all its departments and offices, even if they are not all in the same building or city, providing communication between the organization and the rest of the world. In principle, this task is accomplished by connecting the organization (and all the other organizations) to the network nodes by different types of communication strategies and applications. Since WANs are usually developed by the PTT of each country, their development is influenced by each PTT's own strategies and politics. A WAN consists of collection of machines called hosts, which run various applications. These hosts are connected to a communication subnet, for relaying messages.

18

This subnet comprises of components like transmission lines, switching devices, etc. The switching devices are nothing but dedicated computers for connecting two or more transmission lines. A point-topoint subnet is used while connecting various topologies of LANs while satellite system is another option where satellites help routers. Satellite networks are inherently broadcast and are useful when the broadcast feature is required in transmission. Protocol : These are set of predefined rules which are used by the systems in the network. Protocols defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called Ethernet. Another popular LAN protocol for PCs is the IBM token-ring network . Network Architecture : Networks can be broadly classified as using either a peer-to-peer or client/server architecture. Peer to Peer architecture means the stations participating can behave both as client as well as server while, Client/Server architecture means a dedicated server is present in the network which serves the various clients onto the network. So, to distinguish client from server there are different protocols, which are loaded at client side and the receiver side. Networks can be broadcast or point-to-point too, depending on the transmission technology adopted. Broadcast networks are those, which have a single communication link, which is shared by all the machines or devices on the network. A data can be destined to a single node too by keeping an address field in the outgoing data, process is called unicasting. When a packet in a network is transmitted and every node on the network is receiving it, this working is called as broadcasting. When it is intended only few people but not all should receive that message, then the group address (may be subnet address) to which those user belong is kept in address field and the process is called multicasting. Point-to-Point networks are those, which includes many connections between individual pairs of machines. On the way there are many interfaces through which that packet has to pass. As a general rule, smaller geographically localized networks tend to use broadcasting whereas larger networks usually are point-to-point, however there are exceptions too. Applications of Computer Network Computer networks enables the users placed at various sites to participate in network and communicates/transfers their data from their site to some other place or vice-versa. As nowadays the need of data exchange is growing, networking arena of computers is widely spreading. Some of the applications of computer networks are: 1.

Access to Remote Programs

2.

Access to Remote Databases

3.

Value Added Communication facility.

4.

Personal communication (text, graphics, audio, video)

5.

Resource Sharing

19

Access to Remote Programs With the help of networking one station is able to execute the programs present on different station, this execution takes place at the client side as in networking there are intelligent terminals. This enables transparency between user and the system as user is unable to know that the code was being executed on the same system or different. This is achieved in networking by placing programs on the server and telling the clients the path to reach that program, hence client sitting at remote site can execute the program stored on server’s disk .

Figure Remote program access While performing remote access to the programs it is necessary that the authentication of user is being done. This type of access brings down the software cost as there is no need of installing at each station, instead with the networking they are being kept at a place to which other refer. Access to Remote Databases Networking also helps in accessing the remote databases, i.e data is kept a remote server to which multiple clients It also means that a user is utilizing or referring to the disk of remote server. This prevents redundancy of data. In centralized approach, data is being kept at a place which is then referred by others later.

Figure : Remote database access

20

Value Added Carriers These are the carriers, which leases circuits from other network operators. The service provided by these carriers is known as value added because instead of mere relaying the bits onto network, these carrier performs some sort of processing on the data thereby providing added value to the data communication. This includes remote storage, processing, code conversion, protocol conversion, etc. There are many different value added carriers which exists today and offers value added services, some of them are: -

Electronic Data Interchange(EDI)

-

Voice mailbox

-

Videotex

-

Store and forward electronic mail

-

Electronic Funds Transfer(EFT)

-

Gateways linking different electronic mail services.

-

Airline and Hotel reservation system, etc

The advantage of using this value added carriers is that organization does not requires a common data format for its multiple clients, instead this is taken care of by these carriers. With the help of these carriers the network, which becomes is value-added network (VAN) it uses the communication services of other commercial carriers, using hardware and software that permit enhanced telecommunication services to be offered. Personal Communication (Text, Graphics, Audio, Video) Computer networks permits user on personal basis too, as it allows him to transfer its data, pictures, etc from one place to another. He can connect its PC to its office PC too from his home through the networks. Networks enables fast data access and offers reliability. Resource Sharing The main objective of networking is resource sharing, i.e users can access the common resources available on the network be it files, printers, hard disk, etc. this reduces hardware and software cost. Centralized And Distributed Data Processing Data processing basically means, the act of converting the data so that later some information can be inferred from it. In a networking it has to be decided that where this processing should take place, as there is bulk of data and the processing will be controlled and managed. Like, in various organizations one must have find EDP(Electronic Data Processing) centres. So, Data processing can be categorised into Centralized, Distributed or Decentralized. Centralized Data Processing (CDP) In this architecture, one provides data processing support or a cluster of large computers located in a central data processing facility. Many of the tasks performed by such a facility are initiated at the centre with the results produced

21

at the centre. Each person is provided with a local terminal that is connected by a communications facility to the central data processing facility. Centralized computers: One or more computers are located in a central facility. In many cases, there are one or more large mainframe computers, which require specialized facilities such as air conditioning and a raised floor. In a smaller organization, the central computer or computers are high performance servers or midrange systems. Distributed data processing (DDP): This processing includes main features (shown in Figure 23)like,

•

Many servers spread out over local or wide area networks (WAN).

•

Clients and servers can be located anywhere in the world.

•

Clients and servers are heterogeneous (dissimilar).

•

For performance reasons, network sessions should be "light weight" and to minimize delays, connectionlessoriented protocols should be used.

Figure Features of WAN A DDP facility is one in which small computers are dispersed throughout an organization. The objective of such dispersion is to process information in a way that is most effective based on operational, economic, and/or geographic considerations, or all three. The various computers in the system must be connected to one another. A DDP facility involves the distribution of computers, processing, and data. Until the early 1970’s and since that time, there has been a steady evolution to distributed processing. The key factor that has made DDP possible is the continuing decrease in cost of computer hardware, accompanied by an increase in its capabilities. Client/server Architecture: An organizational approach that is becoming increasingly popular and is intended to provide the best aspects of both distributed and centralized computing. Users work on powerful workstations or PCs,

22

which supports the end-user programming, provides the ability to use off-the-shelf software, and gives the immediate response inherent in distributed architecture. These workstations, or “clients,” are supported by specialized “servers.” This architecture has been made possible by the advent of high-speed local area networks (LANs) and LAN interconnections, along with more sophisticated systems software to provide inter-machine processing. First, it is cost effective and achieves economies of scale by centralizing support for specialized functions. File servers and database servers also make it easier to provide universal access to information by authorized users and to maintain consistency and security of files and data. The physical architecture of the computers (Figure 24)used can be designed especially to support their service functions. Finally, this architecture is very flexible. Services can share processors for smaller information systems, and they can be split among processors in larger systems to provide redundancy, increased capacity, and increased responsiveness.

Figure Client/Server model Thus, the "Client/Server" Model 1.

Central system stores data and part of the programs - The "Server" portion.

2.

Client systems execute the user interface and business logic portions - The "Client" portion.

3.

Clients send "Transactions" to server

4.

Server executes transactions then sends results back to client.

5.

Done over a local area network.

6.

Clients establish a network session with server. Connection-oriented protocols are used.

7.

Clients tend to be homogeneous.

Intranets: In essence, an intranet provides users the features and applications of the internet but isolated within the organization. Key features of an intranet include the following: 1.

Uses internet based standards, such as HTML and SMTP

2.

Uses the TCP/IP protocol suite for local and wide area networking

3.

Comprises wholly owned contend not accessible to the general internet

4.

Can be managed, unlike the internet

23

Extranets: Like the intranet, the extranet makes use of TCP/IP protocols and applications, especially the web. The distinguishing feature of the extranet is that it provides access to corporate resources by outside clients, typically suppliers and customers of the organization. This outside access can be through the internet or through other data communications networks. The extranet provides more extensive access to corporate resources, usually in a fashion that enforces a security policy. As with the intranet, the typical model of operation for the extranet is client/server. Distributed Applications: One application split up into components that are dispersed among a number of machines. One application replicated on a number of machines. A number of different applications distributed among a number of machines. An Internetworked E-business enterprise uses the Internet to interconnect its World Wide Web sites, intranets to other company locations, and extranets to business partners.

E-Commerce Web Sites Internet Links

Electronic Commerce Services Customers

Extranet Links Internet Links

Customer Marketing Services

and

Extranet Links Suppliers

INTERNETWORKED E-BUSINESS ENTERPRISE

Accounting Finance, and H.R. Services

Intranet Links 24 Other Company Locations

Internet Links Supply Chain Management Services

REVIEW EXERCISE 1.

Draw the 7 layers of OSI model. How is the functioning distributed in to these seven layers? Explain every layer in detail. 2. a) What are LAN, MAN and WAN? Explain in brief. b) Write short notes on the various network topologies. Explain the bus topology and its working.

3.

Explain TCP/IP.

the

complete Give

distribution the

of work details

in

the along

4.

Explain the different types of data transmission modes.

5.

Briefly outline the relative merits and demerits of the different network topologies in use.

6.

Explain the following – a) Unshielded twisted pair cable (UTP) b) Fiber optic cables 7. What are protocols? Briefly explain the different types of protocols.

8. What do you understand by client server network? 9. Write a short note on interorganisational networks. 10.Discuss various applications of computer networks. 11.What are the hardware and software requirements of a LAN? 12.What is resource-sharing .How does a computer network helps in resource sharing 13.What do you understand by internetworking? 14.Discuss advantages and disadvantages of OSI reference model.

25

different with

layers

of diagram.

WHAT

IS

THE

INTERNET

AND

WHY

SHOULD

YOU KNOW ABOUT IT? The Internet is a loose amalgam of thousands of computer networks reaching millions of people all over the world. Although its original purpose was to provide researchers with access to expensive hardware resources, the Internet has demonstrated such speed and effectiveness as a communications medium that it has transcended the original mission. It has, in recent years, grown so large and powerful that it is now an information and communication tool you cannot afford to ignore. Today the Internet is being used by all sorts of people and organizations—newspapers, publishers, TV stations, celebrities, teachers, librarians, hobbyists, and business people—for a variety of purposes, from communicating with one another to accessing valuable services and resources. You can hardly pick up a newspaper or magazine without reading about how the Internet is playing a part in someone's life or project or discovery. To appreciate what the Internet has to offer you, imagine discovering a whole system of highways and high-speed connectors that cut hours off your commuting time. Or a library you can use any time of the night or day, with acres of books and resources, and unlimited browsing. Or an all-night, nonstop block party with a corner table of kindred souls who welcome your presence at any time. That's the Internet, and this chapter will tell you why you should know about it. WHEN IT CAME The Internet universe was created by an unassuming bang in 1969 with the birth of ARPANET, an experimental project of the U.S. Department of Defense Advanced Research Projects Agency (DARPA). It had a humble mission, to explore experimental networking technologies that would link researchers with remote resources such as large computer systems and databases. The success of ARPANET helped cultivate numerous other networking initiatives, which grew up intertwined; 25 years later, these have evolved into an ever expanding, complex organism comprising tens of millions of people and tens of thousands of networks. Most users describe the Internet (or the "Net") as a "network of networks"; it appears to stretch forever. It doesn't just connect you and another computer; it connects you and all other Internet-connected computers. Don't think of the Internet as just a bunch of computers, though. It is a perpetually expanding universe with its own geography, "weather," and dynamic cultures. In this cyber-sphere, people in geographically distant lands communicate across time zones without ever seeing each other, and information is available 24 hours a day from thousands of places. Business Use of Internet There are myriad reasons why the business community should be connected to the Internet; indeed, one of the fastestgrowing segments of the Internet today is commercial. The Internet is providing a wonderful environment in which to do business; there are many stories of small and big businesses that have leveraged their relatively small investment in connection costs to search the Internet for information, keep in contact with customers, or provide online services and operate virtual storefronts. Businesses that claim they listen to their customers' needs can now do so on the Internet. Companies exploring telecommuting options for their employees should definitely evaluate the Internet's capabilities. Because so many organizations are linked, with more being added every day, connecting to the Internet is a very attractive alternative to building a private network. Many companies justify joining the Internet to be more accessible to customers, and to have the ability to consult with experts around the world. Just providing Internet connectivity

26

services, consulting, and training is a big business. A growing number of Internet providers—large and small—are competing to connect businesses and schools to the Internet. Domain Name System. There's actually a method to these names and addresses—a naming system known as the Domain Name System, or DNS. The DNS is also the worldwide system of distributed databases of names and addresses. These databases provide the "translation" from names to numbers and vice versa, a sort of international Who's Who of computers. DNS names are constructed in a hierarchical naming fashion, which you can think of as a worldwide organization chart. At the top of this chart are top-level specifications, such as EDU (educational), COM (commercial), GOV (government), MIL (military), ORG (organizations), and NET (networks), and also two-letter country codes, such as US for the United States and CH for Switzerland. An organization can register for a domain name, selecting one of the top-level specifications mentioned above that describes it best, and then preceding it with a recognizable version of its name. For example, the Yoyodyne Software Systems company will have a domain name like yoyodyne.com. From there, it can divide itself into subdomains, extending the organization chart to department levels, or it can just give all of its computers names in the yoyodyne.com domain. Once you understand how this naming system works, you can remember names more easily, and you can also tell things about a computer, such as to what organization it belongs. The names do not, however, always indicate geographical location. For example, planet10.yoyodyne.com may be the main computer at the home office in Grovers Mill, New Jersey, mars.yoyodyne.com may be at the Hong Kong branch, while venus.yoyodyne.com might be located at the Santa Cruz division. Many U.S. organizations and companies use the three-letter designations mentioned above (for example, EDU, COM, and ORG). However, most countries have stipulated that organizations use their two-letter country codes for top-level domains. For example, an actual computer name, quake.think.com, refers to a commercial (COM) enterprise: the computer's name is quake and it belongs to Thinking Machines Corporation (think), a supercomputer manufacturer in the United States. Another example is fujitsu.co.jp, a computer at the Fujitsu Company in Japan (jp is the two-letter country code for Japan). Network News USENET is a worldwide conferencing system, encompassing all sorts of organizations (universities, commercial enterprises, government agencies, even home computers) and supporting one service—news. USENET is a real community. People from all walks of life spend hours "together," reading, contributing ("posting"), and responding. Each group has its regulars, its "Norm Petersons." Others come and go. Some "lurk," while others seem to talk incessantly. USENET is a breeding ground for free expression and thought. People are usually very frank on this network! It's a point of pride that USENET, for the most part, is an open and uncensored environment. As a result, some very explicit and candid discussions ensue, from political arguments, to religious opinions and holy wars, to explicit stories with indecent themes. Be aware of this if you're easily offended, and simply avoid the groups that focus on subjects unpalatable to you.

27

USENET is divided into newsgroups. Devoted to a certain topic, each newsgroup is made up of articles or postings that look like email messages (each has a header and a message body). There are thousands of different newsgroups on USENET, but not every computer or site gets all of these in its USENET feed. Each site can pick which newsgroups it wants to "carry" or let its users participate in. Why wouldn't a site want to provide every single newsgroup? One reason is that volume of daily traffic is huge (over a 100 megabytes per day), and it takes up valuable disk space. Or the site may be paying long-distance charges to transmit and receive traffic, so it participates only in a small number of groups. Another very common reason is that some of the newsgroups deal with explicit subjects that may not be appropriate to carry. USENET newsgroups are similar to email lists, but there are a few differences. With Internet email lists, every message is sent to each person who has explicitly requested to be a participant. On USENET, every newsgroup article is received and stored on each participating USENET computer, instead of being sent to each user. Even when you're not participating in a newsgroup, all of its articles are still stored on the computer, so you have easy access to any you want. It's difficult to know how many people participate or lurk in each newsgroup. Something you say might be read by as few as five people, or by as many as 100,000. USENET Hierarchy and Newsgroup Names. Newsgroups are organized in a hierarchical structure; their names have dots in them, just like Internet domain names. The top-level (left-most) word in the newsgroup name specifies the newsgroup's category. There are seven major USENET top-level categories, and a scattering of alternative categories, as shown below. Knowing what these categories mean can help you figure out what each newsgroup is about.

Major Usenet Hierarchy Categories comp Computer hardware, software, and protocol discussions. misc Topics that don't fit anywhere else, such as job hunting, investments, real estate, and fitness. news Groups that deal with USENET software, network administration, and informative documents and announcements. rec Recreational subjects and hobbies, such as aviation, games, music, and cooking. sci Topics in the established sciences, such as space research, logic, mathematics, and physics. soc Groups for socializing or discussing social issues or world culture. talk Lengthy debates and discussions on various current events and issues—politics, religion, the environment, and so forth.

28

SOME ALTERNATIVE HIERARCHIES alt Alternative group of discussions—not carried by all USENET sites. Some are controversial; others are "lite." Not considered a regular part of the USENET hierarchy. Alt newsgroups generate a lot of traffic. bionet Topics of interest to biologists. biz Business-related groups. clari Commercial news services gateway'ed to USENET by the ClariNet Communications Corporation. k12 Conferences devoted to K-12 education. relcom Russian language newsgroups. A Sampling Of Newsgroups rec.food.cooking alt.internet.services rec.humor.funny soc.men comp.society news.announce.newsgroups biz.jobs.offered alt.exotic-music rec.motorcycles soc.culture.french sci.energy Access to USENET. not everyone on the Internet has access to USENET. There's no one way to tell if you can participate, but with a little bit of sleuthing, you might have a better idea. Most universities and individual commercial Internet providers provide access to USENET newsgroups. Many businesses carry a subset (or all) of the groups. Remember, you can (and should) always call your provider's help desk and ask. News Readers. In order to read or post news, you need to have a news reader program. There are thousands of newsgroups, and you don't want to have to sift through every one of them. A news reader will let you select which newsgroups you want to participate in by allowing you to "subscribe" to them (without having to send email to an administrator). The reader program will organize the newsgroups, display the articles for you to read, and allow you to post articles. Just as there are many email programs, there are many news readers. Some are user-friendly, while others use terse commands and are difficult to learn.

29

You'll have to get used to how your news reader works and how it displays newsgroups and articles. Some readers offer a "threaded" function that organizes articles within a newsgroup according to discussion threads—a helpful feature if you want to follow a particular discussion within a newsgroup instead of hopping from one debate to another. Getting Started. Once you're able to access USENET news, the first thing you should do is read all the articles in the news.announce.newusers newsgroup. The many useful articles in this group are regularly updated and chronicle the history of USENET, explain concepts and common problems, provide a list of frequently asked questions along with the answers, give information on available news readers, explain USENET software and how to become a USENET site, and provide lists of USENET groups. If you have new-user questions, there is a newsgroup where you can post them, the news.newusers.questions group. Posting Articles. When posting an article in a newsgroup, you're asked for some information. As when you send email, you're asked for a subject. Be descriptive, since there are many people participating and it's polite to give them a good idea of what your posting is about.You also need to specify how far and wide you want your article distributed. Many times you'll want to make sure that everyone in the USENET world can read it, but sometimes your article may apply to a local geographic area. For example, if you post an article asking if anyone has any tickets to the Bryan Adms concert on Friday, you probably want to restrict it to your home town of Delhi rather than sending it to Tokyo and everywhere else. It's important that you exercise good judgment, not only by specifying geographic areas, but also by posting articles only to appropriate newsgroups. For example, it's probably not the best idea to post your resume to rec.folk-dancing. If you write an article that is relevant for more than one newsgroup, you can cross-post that article. For example, you may decide that your article posted to rec.cooking about how you almost burned the house down cooking dinner should also be posted to the rec.humor newsgroup. Be careful when cross-posting, though. Sometimes it can anger the regulars in the cross-posted newsgroups because you're essentially "forcing" them into a conversation that originated somewhere else.

Moderators The normal operation for most email lists and USENET newsgroups is to let everyone participate, sending or posting whatever they want. As you can imagine, this practice quite often results in what's called a low signal-to-noise ratio— lots of junk submissions that offer little or no quality to the discussion. As a preventive measure, some email lists and newsgroups are moderated. Instead of being sent straight to the group, messages or articles are submitted to a moderator, who decides whether or not the submission has relevance to the topic at hand. The moderator may accept (or reject) each submission or may combine messages and articles to create a digest that gets posted periodically. Moderated lists and newsgroups usually contain a higher proportion of useful information, but many people don't like the idea of their postings being evaluated.

30

NETWORK CONNECTIONS We are sure by now you must have been fascinated by the world of Internet. Let us take you one step further by telling you how to get an Internet connection. There are many types of connections you could get on the internet depending on the type of use and the amount of resources (money) available. The different types of connections, their advantages and limitations have been discussed. Types of Connections No matter what type of connection you go in for, it should be reliable, fast, easily available, and economical. There is no such thins as a free connection to the Internet. Someone, somewhere has to pay for the equipment, software, telephone lines, and electricity. Basically there are four types of connections to the Internet: 1.

Dial-up Connection

2.

ISDN Connection

3.

Leased Line Connection

4.

Cable Modem

The most popular type of connection for an individual is the dial-up connection as it is easily available and economical. Dial-Up Connection As the name suggests, dial-up link means you have to dial into a modem over a telephone line before you can get connected to the internet. A modem (modulator demodulator) is a device which converts digital signals emitting from the computer into analog signals so that the data is easily transmitted over analog telephone lines. At the receiving end, there is another modem which converts these transmitted analog signals back to the digital form which are received by the target computer. For this type of connection you require: 1.

A computer whose configuration could be 80486 but the best is Pentium-III or above.

2.

Communication software, like dialer which the Internet connection provider will give.

3.

A telephone line.

4.

A modem (optimal speed is 36.6 kbps). These days we use modems of speeds up to 56 kbps.

5.

Software like a browser, e-mail programme, FTP software, Newsgroup reader, Eudora, Outlook Express, etc. Outlook Express is one of the software which helps to read news and mail offline once they have been collected online.

There are 3 major ways by which you can get linked to the Internet using a dial- up conncetion, namely; A.

Host terminal connection

B.

Individual computer

C.

Dial-Up or on demand through the LAN.

A.

Host Terminal Connection (Terminal Emulation)

31

In case of host terminal connection, a PC is connected to some Internet host via modem and a terminal emulation programme is run. Your terminal now acts like a vt-100 terminal . In other words, you are connected to a large computer which is connected to the Internet. Thus if want to download a file, the file is downloaded to the host and not your computer. To download a file from their host to your computer you need to have some specific software. In this type of connection you can download only text but not graphics. Hence, a host terminal connection is also referred to as a shell account. This account is best suitable for : 1.

Students whose budget is low and their requirement is limited to text.

2.

Users who connect via Telnet programmes.

3.

Users whose frequency to use the Internet is low.

4.

users who want to use the Internet to access the network of their workplace from their home place (personal account). Such users could connect via Telnet.

5.

Jobs where multi-tasking is not required. This connection permits only one task at a time, eg., the user cannot read the news as well as download a file.

This type of a connection offers three different types of accounts depending on your distance from the ISP and the nature of work for which you want the connection. 1.

Local dial.

2.

Use of public data networks.

3.

Restricted access.

1.

Local Dial . Local dial is the cheapest type and is only possible if the host is at a local telephone call distance away.

2.

Public Data Network. If the host is not in the vicinity, then long distance calls have to be made over public data networks. If the speed of such networks is slow then data transmission speed will also be slow and so the connection will prove to be more expensive.

3.

Restricted Access Account. Suppose you want to access only E-mail or newsgroups. In such situations, restricted access account is best for you. There certain sites which provide inexpensive E-mail accounts, local bulletin board services, etc. you just have to registered pay only for the services you want to use.

B. Individual Computer Here your computer can work as an Internet Host, I.e., direct downloading of files and mails can be done when connected to the internet. This kind of link is a little more costly than the host terminal connection as you have to pay a monthly fees to the service provider or sometimes even a flat charge for a fixed period of time. Here you can have one or both the following account ; 1.

Serial Line Internet Protocol (SLIP)

2.

Point to Point Protocol (PPP)

32

1.

Serial Line Internet Protocol (SLIP) . In case of SLIP data is sent in packets under speeds of 9600 bps on telephone lines using data compression protocols.

2.

Point-to-Point Protocol (PPP). In case of PPP data is sent over telephone lines via modem. Double checking is done at the destination to see if data packets have arrived intact. This is better than SLIP as it allows authentification of users. These days PPP connections are more common. Again, speed of data transfer in PPP is faster than in SLIP.

This type of connection is good for people who: 1.

Use Graphics.

2.

Download files often.

3.

Use direct e-mail or any other online service.

4.

Use Internet regularly though for limited hours.

The limitations are few, such as , people may not be able to access the Internet easily if the disk space is limited or if the line is slow (i.e., speeds below 28.8 kbps will not be accessible by other people). C. Dial-Up or On-Demand through the LAN In this case there is a dial up link from the LAN to which you are connected to. This type of connection is favourable for small business houses and educational institutes. Here the server, on demand, dials up for a connection and once the connection is established everybody logged on to the LAN can access the Internet. In such a situation if there is any file downloaded from the Internet then like any other file, this file will be accessible to all LAN clients. The only problem here is that the more the number of users logged onto the LAN and working on the Internet, the slower will be the Internet connect6ion. However, this is successful if you have a very fast server software along with a very fast line. Again extra software like proxy servers are also required to serve the needs of various individual LAN users with one Internet connection. Integrated Services Digital Network Connection (ISDN) This is a very high speed connection to the Internet over normal telephone line. It combines both voice and digital information in a single medium, making it possible to provide the customers with digital as well as voice connections. In ISDN connection, the information which is sent from your computer to the Internet is digital. Here we do not use a normal modem. As no conversion from analog to digital or vice versa is required, so we use an ISDN modem which is merely a terminal adapter. Another differences lies in the fact that the ISDN lines, in order to work, require power from outside. When there is a power shutdown, ISDN lines will not work. ISDN service has many variations but we follow Basic Rate Interface (BRI) Service. Here the ISDN line is divided into three logical channels, namely : 1.

Two 64kbps B (bearer) channels.

2.

One 16 Kbps D (Data) channel.

Thus ISDN is commonly referred to as 2B+D.

33

Over bearer channels you can send data. If only data is sent then it could be sent at a speed of 64+64=128 kbps but if both data and voice is to travel then one B channel is dedicated to voice and the other to data. The data or D channel is used to send signaling information for routing data which is being sent over B channels. Those telephone companies which do not have the ability to use D channels remove 8 kbps from each B channel. Therefore, only 56(8+4) kbps of data can go over each of these B channels. Apart from voice, many value added services are also being offered like : 1.

Telephones will soon have the facility to display name, address, and telephone number of the caller while the telephone rings.

2.

When the telephone gets connected to the computer, the caller’s database record is displayed on the computer.

3.

Call forwarding facility

4.

Remote electricity meter reading services.

5.

Smoke alarms that automatically call up the hospital, fire station or police station.

ISDN follows recommendations laid down by CCITT(Comite Consultatif International Telegraphique et Telephonique) which is a body that lays down rules for data communication and telephones. Advantages of using ISDN: 1.

Allows high speed access, i.e., 128 kbps.

2.

No special laying down of wires. The existing copper telephone cables work fine.

3.

Can be used for voice, data, graphics, full motion video as data transfer speed is high.

The only disadvantage of using ISDN is that it proves to be an expensive affair as special equipment is required for it and the tariff is also high. Leased Line Connection (Dedicated Connection) As the name suggests, a leased line connection is a permanent connection laid down between you and a modem. As it is permanently lined, you have a 24 hour access to the Internet, seven days in a week. A leased line connection is very useful especially when frequent information has to be accessed from the Internet and also when the volume of data transfer is high. It is also useful if the Internet is to be used for more than 12 hours a day. This type of connection is the most reliable and has high speed. The only issue behind this connection is its cost. The cost includes : 1.

One time installation (laying down of physical line upto your site).

2.

Yearly/periodically maintenance charge.

3.

Annual tariff.

4.

The necessary one time hardware, software and set up charges.

Cable Modem In case of cable modem the Internet can be accessed through the normal coaxial television cables with the help of cable modems. Speed of cable modems is 10 to 100 times faster than normal dial-up connection modems. The only catch is

34

that the local cable operator should have the capability to access the Internet over cable TV wires and that cable modems are slightly more expensive than normal modems. One advantage of cable modem connection is that you need not have a telephone line if you want this type of connection to the Internet. Before giving approximate tariff rates for the different types of connections, let us discuss the role of Videsh Sanchar Nigam Limited (VSNL). VSNL is the gateway to Internet in India. It is also an Internet Service Provider (ISP) so that the user can acquire a connection from it. Until recently, VSNL was the only gateway of the Internet in India but now we have another private gateway, namely, Now Convergence. This organization also has some very good offers like faster downloads. Let us now discuss the role of an ISP. Internet Service Provider (ISPs) An ISP sells monthly/hourly connections to the Internet. Initially, VSNL was the only ISP in India but as surfing the Internet became popular, many Indian companies have come forward. Some popular Indian ISPs are :

Table Cable Modem Connection S. No.

Name of ISP

URL

1.

Satyam Online

www.sify.com

2.

Dishnet DSL

www.ddsl.net

3.

Cal Tiger

www.caltiger.com

4.

Pacific Internet

www.pacific.co.in

5.

Power Surfer

6.

BPL Net

www.bplnet.com

7.

Roltanet

www.roltanet.com

8.

Net 4 India

9.

Zee Next

10.

Now

www.now.com

11.

MTNL

www.mtnl.com

12.

VSNL

www.vsnl.com

www.powersurfer.net

www.net4india.com www.zeenext.com

The registration forms are available on the Internet itself on the websites of the ISPs. There are a number of factors to be considered before selecting an ISP, a few of them are as follows : 1.

What type of account is being offered ?

2.

What is the reputation of that ISP?

3.

What is the fixed monthly charge, if any?

4.

For what time period and for how many hours is the connection being given? For example, an ISP may be giving you 100 hours of Internet access time to be used within six months.

35

5.

What kind of support is given by that ISP, i.e., does he help in troubleshooting problems with respect to Internet?

6.

How reliable is the connection and how many lines are available, i.e., does the user has to struggle in order to get a connection or there are many numbers, so that if one telephone line is busy the user can try another?

7.

If a user decides to continue with same ISP after his time period has elapsed or the number of hours have expired, then what benefits does he get?

8.

Now in order to use the Internet, first install the TCP/IP protocol and then configure it. After that test the connection.

Installation of TCP/IP Protocol Step 1 : Click the Start button, select Setting and then click the Control panel or go to the Control Panel folder by double clicking the My Computer icon in the desktop.

Step 2 : In the3 Control Panel window, double click the Network and dial up connection icon (Figure)

36

Step 3 : The Network dialog box appears. If you have already installed the TCP/IP Protocol, go to the next step. If not, click the Add button

37

Step 4 : Right click on Local area connection and then click properties

38

Step 5 : Click on Internet Protocol

39

Step 6 : Now if your ISP assigns the address dynamically then click the obtain an IP address automatically but if you are given an IP address then click the Specify an IP Address, and then fill in the IP Address and Subnet Mask : Boxes. Enter the Gateway address and in DNS Server enter the DNS server address and then click the OK button.

40

Configuring the Dial Up Networking Step 1 : Double click the Dial up and Networking icon in Control panel.

Step 2 : Double click on make new connection

41

Step 3 : Click on Next Button to configure Dial Up Connection

42

Step 4 : From the above given options Select the second option i.e. Dial-up to the Internet and then Click on Next to continue configuring Dial up Connection.

43

Step 5 : Select the first option and click next.

44

Step 6 : Now you can install your modem. Computer will try to install the modem software automatically. But, by checking the box you can install it manually.

45

Step 7 : Click on finish option to complete the configuration of your dial up connection. INTERNET PHONE In 1995, for the first time, voice travelled over the Internet and ever since there has been no looking back. Internet telephony or Voice over IP (VoIP) refers to communication services like voice, fax and voice-messaging applications, that are transported via the Internet, rather than the Public Switched Telephone Network (PSTN). IP Telephony enables telephone voice calls to be received over the Internet and other networks based on it. The IT managers will be benefited as telephone calls over the corporate data network lead to substantial cost savings. Additionally, it is now possible to carry Voice over IP (VoIP) over a wide variety of networks ranging from IP to ATM to the PSTN. Though there are many obstacle in the way of adoption of IP Telephony, yet it’s most promising areas in the future seem to be corporate intranets and commercial extranets. Today Network telephony is emerging as one of the most important and fast growing industries. What is IP Telephony IP telephony is the conveyance of voice, fax and related services, partially or wholly, over packet-switched IP-based networks. There are basically four ways by which you can make a call : a. PC to PC : This telephony works only if both parties use Internet Phone Software. b. PC to Phone : Many software developers now offer PC telephone software but, these days gateway servers are emerging to act as an interface between the Internet and the PSTN. These are equipped with voice-processing cards, therefore users can communicate over normal standard phones c Phone to PC : A call goes over the local PSTN network to the nearest gateway server, which digitizes the analog voice signal, compresses it into IP packets, and moves it onto the Internet for transport to a gateway at the receiving end. d. Phone to Phone : A call goes over the local PSTN network to the gateway server, which, in turn, is connected to the Internet which forwards it to the gateway server of the called party. This is then forwarded to the PSTN Network of the called party, which, in turn, forwards the call to the called party The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format, and compression/translation of the signal into Internet Protocol (IP) packets for transmission over the Internet; the process is reversed at the receiving end. In other words IP Telephony will enable telephone voice calls to be received over the Internet and other network based on it. Configuration of PC for VoIP Minimum configuration required for VoIP is a Pentium machine (Figure ) equipped with the following :

46

1.

Audio Card

2.

Video Card

3.

Speakers

4.

Microphone

5.

Modem

6.

CD ROM

Factors which have Led to the Growth of IP Telephony 1.

Development of modern packet based networks has led to :

a.

Efficient bandwidth utilization.

b.

Concurrent transfer of data, voice, video etc.

2.

Convergence of conventional telephone traffic with data networks.

3.

Many flavours of IP telephony exist depending on the nature of use. Certain products have to be installed if VoIP has to be set up on an existing PBX installation as it could be that existing equipment is incompatible.

Technical Barriers for IP Telephony 1.

Low bandwidth limits the sound quality and reliability Loss of packets leads to gaps in conversation and abrupt speech ending.

2.

The increasingly heavy use of the Internet’s limited bandwidth often results in congestion which, in turn, can cause delays in packet transmission. Such network delays mean packets are lost or discarded.

3.

Since packets travel over different paths it also increases the chances of packet loss.

4.

Different vendors have used different protocols. Therefore, many IP telephony products developed by different companies may not be able to interact with each other.

5.

Since a variety of speech-compression protocols and speech coding algorithms are used, having different bit rates and mechanisms for reconstructing voice packets and handling delays produces varying levels of intelligibility and fidelity in sound transmitted over the Internet.

IP Telephony Standards The International Telecommunication Union (ITU) has given the H.323 specification (a set of recommendations) which defines how voice, data and video will travel over IP based LANs. This standard looks into 3 aspects. 1.

The Audio Codec : Adoption of audio codec standard will improve reliability and the quality of sound over IP network.

2.

The Transport Protocols : The RTP protocol has control mechanism to synchronise different traffic streams.

47

3.

The Directory Services : Directories are required to ensure interoperability between the Internet and the PSTN phones.

Opportunities And Benefits Due To IP Telephony 1.

Lower costs to consumers particulary on long distance international calls as cost is independent of distance.

2.

Facilitation of introduction of newer technologies as IP based networks cost less.

3.

Creation of many opportunities, especially for telephone operators.

Difficulties Which Have Resulted Due To IP Telephony 1.

Due to lower costs involved in IP telephony, domestic conventional circuit switched networks are the major sufferers as they face stiff competition from their counterparts.

2.

Reduction in revenues, specially from international calls, leading to reduction in funds to be used for the extension of domestic network.

3.

The shift from PSTN networks to IP networks has also reduced in allocating substantial resources to human resource development.

Acceptance of IP Telephony Government have adopted different approaches towards IP telephony. Some have licensed it, some have prohibited it, and some do not regulate it all. The following table shows a study of the status of IP telephony in six countries : Table IP Telephony Status Country

Legal Status

Bolivia

Forbidden except for licensed operators

Egypt

Forbidden except for licensed operators

Hungary Nepal

Allowed for international traffic Voice over IP forbidden except for licensed operators. Fax over IP

allowed Singapore Uganda

Allowed Forbidden except for licensed operators

Summary IP telephony, also known as Voice over IP, has taken a firm hold in markets all over the world. It can generally be offered to customers at prices that are much below those offered by conventional circuit-switched networks, particularly on long-distance and international calls because traffic pricing on IP-based networks is largely independent of distance.

48

It is estimated that around four billion minutes of voice and fax were carried internationally over IP-based networks in the year 2000

Web Browsers A Web browser contains the basic software you need in order to find, retrieve, view, and send information over the Internet. This includes software that lets you:

•

Send and receive electronic-mail (or e-mail) messages worldwide nearly instantaneously.

•

Read messages from newsgroups (or forums) about thousands of topics in which users share information and opinions.

•

Browse the World Wide Web (or Web) where you can find a rich variety of text, graphics, and interactive information.

Browsers such as Microsoft® Internet Explorer 6 include additional Internet-related software. For example, with Internet Explorer 6, you also get:

•

Outlook® Express messaging and collaboration client

•

Microsoft Windows® Media Player

•

NetMeeting® conferencing software

•

ActiveX® controls

•

Chat

•

DirectX® application programming interface

•

Subscriptions for automatic Web page updates

•

Dynamic hypertext markup language (HTML)

You also can download various Microsoft software programs that work with Internet Explorer 6. When you are using Internet Explorer 6, it will automatically ask you if you want to download software required on other Web sites with its install-on-demand feature.

49

Outlook Express This is a versatile, full-featured e-mail program to send and receive e-mail, and participate in Internet Newsgroups. A simple setup wizard helps you get started and if you're switching from another e-mail program, the import function lets you transfer your address book and messages. Windows Media Player This allows you to see and hear live and recorded broadcasts—such as concerts or breaking news with synchronized audio, graphics, video, uniform resource locators (URLs), and script commands. And streaming technology allows you to see or hear the information as it arrives instead of having to wait for the entire file to download. NetMeeting conferencing software With a sound card, speakers, and a microphone, you can talk to others worldwide—from family to colleagues—using NetMeeting. Add a Windows operating system-compatible video capture card and/or camera to see them, too. Exchange pictures and draw diagrams on an electronic whiteboard, communicate with text-based chat, transfer files, and share applications. ActiveX controls ActiveX technology (first developed for Internet Explorer 3.0) allows authors to develop innovative, highly interactive Web sites. ActiveX controls are the software components that run behind the scenes in Internet Explorer so that these sites come alive for you. MSN Messenger This program lets you converse online in real time with one or more people. You decide how your message is displayed —text only or text with graphics. You can send and receive sounds, files, and links of e-mail addresses, Web pages, and newsgroups. You can even "whisper" to another person in a group chat. Use it for your next online family reunion. DirectX application programming interface DirectX allows you to experience television-quality video and CD-quality audio, while minimizing file size and download time compared with other video and audio formats. With DirectX, what you experience with your computer is better 3-D graphics and impressive music and audio effects. Subscriptions This feature delivers preferred information straight to your desktop, when you want it, in the way you want it—for free (Internet connect charges may apply). To subscribe to a Web site, select the site and specify when you want the information updated and how you want to be notified, such as through an e-mail message. Internet Explorer does the rest. Then you can browse the content offline. Dynamic HTML Internet Explorer 6 supports this programming language, which makes enticing, unique, fun, and fast-downloading Web pages possible. The pages download quickly because they are created using lightweight HTML instead of heavyduty graphics. Round-trips to the server are minimized, which means faster browser performance on your desktop computer.

50

What is a URL?

A URL (or uniform resource locator) is the address of an Internet page on a Web site. Usually it consists of four parts: protocol, server (or domain), path, and filename. Often, when you go to the very first page of a Web site, called the home page, there's no path or filename. Here's an example: http://www.microsoft.com/windows/default.asp

•

http is the protocol

•

www.microsoft.com is the server

•

windows/ is the path

•

default.asp is the filename of the page on the site

Working with Internet Explorer Spot the links You can tell whether an item on a page is a link by moving the mouse pointer over the item. If the pointer changes to a hand, then the item is a link. A link can be a picture, a three-dimensional image, or colored text. Click any link on a Web page to go to another page within that site or another site. Display all Web pages faster To display Web pages faster:

1.

On the Tools menu in the browser, click Internet Options.

2.

Click the Advanced tab.

3.

In the Multimedia area, clear one or more of the Show pictures, Play animations, Play videos, or Play Sounds check boxes.

4.

If the Show Pictures or Play Videos check box is cleared, you can still display an individual picture or animation on a Web page by right-clicking its icon and then clicking Show Picture.

5.

If the pictures on the current page are still visible after you clear the Show pictures check box, you can hide them by clicking the View menu and then clicking Refresh.

51

Display previously viewed pages faster To display previously viewed pages faster:

1.

On the Tools menu in the browser, click Internet Options.

2.

On the General tab, click Settings.

3.

To create more space to store pages temporarily, move the slider to the right.

4.

To prevent Internet Explorer from updating pages in the Temporary Internet Files folder, click Never.

Change how page colors are displayed To change how page colors are displayed:

1.

On the Tools menu in the browser, click Internet Options.

2.

Change the settings as needed.

Display text in a different font To display text in a different font:

1.

On the Tools menu in the browser, click Internet Options.

2.

On the General tab, click Fonts.

3.

In the Proportional and Fixed-width font lists, click the fonts you want.

Specify which font and color setting to always use To specify which font and color settings to always use:

1.

On the Tools menu in the browser, click Internet Options.

2.

On the General tab, click Accessibility.

3.

Change the settings as needed.

Display text larger or smaller On the View menu, point to Text Size, and then click the size you want. View Web pages in a different language Some Web sites offer their content in several languages. You can add languages to your list of languages in Internet Explorer so that you can view these sites in your preferred language. To view Web pages written in a different language:

52

1.

On the Tools menu in the browser, click Internet Options.

2.

On the General tab, click Languages.

3.

Click Add.

4.

Select the language you want to add.

o

If you speak several languages, you can arrange them in order of priority. If a Web site offers multiple languages, it will supply content in the language with the highest priority.

o

Adding languages does not guarantee that you have a font that can display Web pages in your preferred languages.

Add A Page To Your Favorites To add a page to your collection of favorite pages: 1.

Go to the page that you want to add to your collection of favorite pages.

2.

On the Favorites menu, click Add to Favorites.

3.

Type a new name for the page if you want to.

o

To open one of your favorite pages, click the Favorites button on the toolbar and then click the page you want to open.

o

To keep track of your favorite pages, you can organize them into folders. Click the Create In button in the Add to Favorites dialog box.

Add Microsoft Product Insider to your Favorites To make sure you always have access to the latest Internet news, software updates, and tips and tricks for using Internet Explorer and other Microsoft products, why not add the Microsoft Product Insider site to your Favorites list now? To add Product Insider to your Favorites list, follow these steps:

1.

On the File menu of your Internet Explorer toolbar, point to New and click Window so you don't lose your place in this guide.

2.

On the File menu in the new window, click Open, and then type http://www.microsoft.com/insider/ in the address box.

3.

Click OK.

4.

When the Microsoft Product Insider home page has finished loading, on the Favorites menu, click Add to Favorites, and click OK.

5.

Close the new window.

53

Organize your Favorites into folders To organize your favorite pages into folders:

1.

On the Favorites menu, click Organize Favorites.

2.

Click Create Folder, type a name for the folder, and then press ENTER.

3.

Drag the shortcuts in the list to the appropriate folders.

o

You might want to organize your pages by topic. For example, you could create a folder named Art for storing information about art exhibits and reviews.

o

If the number of shortcuts or folders makes dragging impractical, you can use the Move button instead.

Find Favorites more quickly in an overloaded Favorites menu To scan a large Favorites menu more quickly:

1.

On the Windows Start menu, point to Find and click Files or Folders. Windows will display a Find: All Files dialog box.

2.

In the Look in dropdown box, type c:\windows\favorites, or browse to this directory.

3.

In the Named dropdown box, type the filename you are looking for and click the Find Now button. Windows will display all the Favorites that match your query and list information about each.

4.

If there are multiple results, you can click the column information title and sort the results by name, date, and so on.

Edit Favorites You can do a lot more with your Favorites folder list in Internet Explorer 6 than you can with other browsers. Remember these tips:

•

You can drag a Favorite or folder to different areas to reorganize.

•

By going to the Start menu, pointing to Find, and clicking on Files or Folders, you can select a Favorite or folder from the list box and drag it to your desktop.

•

Right-click a Favorite or folder to display a pop-up menu that lets you perform functions like Edit (in the Microsoft FrontPage® Web site creation and management tool), Subscribe, Copy, and Delete.

•

You can click the Send To option to send the Favorite to a floppy disk, create a shortcut on the desktop, or attach the shortcut to an e-mail message.

54

Change your home page To change your home page: 1.

Go to the page that you want to appear when you first start Internet Explorer.

2.

On the Tools menu, click Internet Options.

3.

Click the General tab.

4.

In the Home Page area, click Use Current (to restore your original home page, click Use Default).

Save text and graphics from the Web When you see text or graphics on a Web page that you like or want to refer to later, you can save them on your computer's hard disk. Later, you can open the saved file and review it offline. To save a text or source file:

1.

On the toolbar, click File, and then click Save As.

2.

Click Save to save the file.

To save a graphic: 1.

Right-click the graphic.

2.

On the shortcut menu that appears, click Save Picture As.

3.

Browse to the folder where you would like to save the file.

4.

Click Save to save the file.

To open a saved file, double-click it from the folder where you've saved it. Internet Explorer will start automatically, and your saved file will appear in the browser window. Add a page to your Links bar To add a page to your Links bar:

•

Drag the icon for the page from your Address bar to your Links bar.

•

Drag a link from a Web page to your Links bar.

•

Drag a link to the Links folder in your Favorites list. You can drag it directly to the Favorites menu and then into the Links folder, or you can drag it to the Links folder when displaying your Favorites in the Explorer bar.

You also can organize your links by dragging them to a different location on the Links bar. Create a desktop shortcut to the current page

55

Right-click the page, and then click Create Shortcut. If the Internet Explorer window is not maximized, you also can create a shortcut by dragging a link from the Internet Explorer window to the location you want, such as your desktop or a folder. Return to a Web page you've already seen There are several ways to return to a previously viewed Web page:

•

To return to the last page you viewed, you can click the Back button on the toolbar or press the BACKSPACE key.

•

To see a list of the last few pages you visited, click the small down arrow beside the Back or Forward button. Then click the page you want.

•

If you want to view one of the last five pages you visited in this session, click the File menu and click the page that you want to go to. This list is started fresh every time you start Internet Explorer.

•

To view more pages, including pages you visited in previous sessions, click the History button on the toolbar and then click the appropriate folder.

Change the appearance of the toolbar To change the appearance of the toolbar:

•

You can move or resize the Address bar and Links bar by dragging them up, down, left, or right. You can even move them into the menu bar. If they won't move, right-click on the bar and uncheck Lock the Toolbars, then leftclick on the word Address or Links and drag the bar where you want it to go.

•

To make more room on your screen, you can hide toolbar button labels. Just right-click the toolbar, click Customize, and select No text labels from the Text options dropdown list.

•

You can hide the Address bar or Links section of the toolbar by right-clicking the toolbar and clearing the check mark for each item you want to hide.

•

You can add items to the Links bar by dragging the icon from the Address bar or dragging a link from a page.

•

You can rearrange items on the Links bar by dragging them to a new location on the bar.

•

You can use smaller Microsoft Office-style toolbar buttons. On the View menu in a browser window, select Toolbars, then select Customize. Under Icon options, choose the size you want.

Use pop-up menus for quick access Internet Explorer 6 features pop-up shortcuts to functions like Save As, Open, and Copy. To access a pop-up menu: 1.

Place the mouse cursor on a hypertext link, graphic image, or Web page, and right-click.

2.

Internet Explorer will display one of three pop-up menus you can use to quickly perform the desired function. Pop-up menu functions include:

56

Add

to

Favorites

AltaVista

Home

AV

Translate

Back Copy

Background

Copy

Shortcut

Create

Shortcut

E-mail

Picture

Encoding Forward Go

to

My

Open Open

Pictures Link

Link

in

New

Print

Picture

Print

Target

Window

Properties Refresh Save

Background

Save

Picture

As

Save

Target

As

Select

All

Set

as

Set

as

Show

Background Desktop

Item

Picture

View Source The Cache and Toolbar You've arrived at this page, so you already know something about how to use a Web browser. Just in case you haven't yet used some of the features of Microsoft Internet Explorer, here's a guide to them. Cache When you explore the World Wide Web, your browser keeps track of the pages you've visited and saves them on your hard disk so they'll load faster when you return to them. This saves you time and money because you can view the saved pages without being connected to the Internet. The saved files, your "Temporary Internet Files", are stored in your disk cache.

To empty your disk cache When you browse, your disk cache can fill up with files you no longer need. Here's how to empty your Internet Explorer disk cache. For Internet Explorer 6:

1.

On the Tools menu of your Internet Explorer toolbar, click Internet Options.

57

2.

Click the General tab.

3.

In the Temporary Internet Files area, click Delete Files, and then click OK.

4.

Click OK to close Internet Options.

To change the size of your Internet Explorer disk cache You can change the amount of hard-disk space reserved for your disk cache. A larger disk cache may display previously visited pages faster, but it will decrease the amount of hard-disk space available for other files. Here's how to set the size of your disk cache. For Internet Explorer 6:

1.

On the Tools menu of your Internet Explorer toolbar, click Internet Options.

2.

Click the General tab.

3.

In the Temporary Internet Files section, click Settings.

4.

In the Temporary Internet Files Folder section, drag the arrow on the Amount of Disk Space to Use slider to the percentage of disk space you want designated for your disk cache, and click OK.

5.

Click OK to close Internet Options.

Toolbar The Microsoft Internet Explorer toolbar consists of buttons that are shortcuts for menu commands. They make browsing faster and easier. Click any button on the toolbar below to find out its function.

Back. Lets you return to pages you've viewed, beginning with the most recent. With Microsoft Internet Explorer 6, right-click the Back button and select from a list of recently visited sites. Forward. Lets you move forward through pages you've viewed using the Back button. With Internet Explorer 6, rightclick the Forward button and select from a list of recently visited sites. Stop. Halts the process of downloading a Web page. Click this if you want to stop downloading a page for any reason —for example, if you're having trouble downloading it or if you don't want to wait for it to download. Then try downloading it again or browse elsewhere.

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Refresh. Updates any Web page stored in your disk cache with the latest content. When you return to a page that you've visited, your browser displays the file stored in your disk cache, rather than the current page on the World Wide Web. This saves download time. Home. Returns you to your home page. You can designate any Web page as your home page. Search. Displays a choice of popular Internet search engines in the left pane. Your search results appear in the left pane, too. When you click a link, the page appears in the right pane, so you don't lose sight of your search results. Favorites. Displays a list of the sites—and, with Internet Explorer 6, the folders, files, and servers—that you've saved as Favorites. Click any item in the list to jump to it. Media. Displays a list of audio and video media options. History. Shows a list of Web sites you've visited. Mail. Connects you to the Microsoft Outlook Express messaging and collaboration client so you can read e-mail and newsgroup messages. Print. Prints the page you're viewing. This is one way to save information from the Internet so that you don't have to reconnect to view it again. You can even print the URL associated with each hyperlink, making it easy to navigate to the site later. Edit. Opens a file in the Microsoft Word word processor that contains the HTML code for the page you're viewing so you can see and even edit it. Messenger. Opens Windows Messenger. Working with Netscape • • • • • • • • • • • • • • • • • •

Understanding pages and frames Knowing that every page has a unique URL Finding, starting and stopping links Linking via buttons and menu items Using history and bookmark lists Choosing the screen look Changing styles, fonts, and colors Selecting a home page Viewing inline images Viewing external images Filling in forms Setting up email and news Receiving and sending email Using the Mail window Using the Message Composition window Receiving and sending news Using the News window Exploring Usenet news

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• • • •

Saving pages Printing and finding Identifying secure information Understanding public key technology

Understanding Pages And Frames You're probably comfortable with the idea that information on the Internet is presented on pages you see on the screen. Even the navigational concepts are pretty easy:

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You start with a home page.

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You click on highlighted words (colored or underlined) in a page to bring another page of related information to your screen.

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You click on arrow buttons to go back (or forward) to a page you have previously seen.

Plus, you can go directly to pages that interest you by choosing menu items:

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History items in the Go menu display pages you have viewed before.

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Bookmarks items in the Bookmarks menu display pages you have designated as worthy of easy access.

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Directory items in the Directory menu display pages that help you use Netscape and Internet features.

Ideally, the act of finding pages becomes secondary to what you really care about: the page's content. Like pages of a magazine, you'll want to flip from one screen page to another, sometimes to continue with the same article and other times to begin a new article. But you can't hold screen pages in your hands like you can a magazine. Screen pages are rarely uniform in length and, displayed one page at a time, don't provide intuitive feedback on where the information begins and ends. So even though Internet pages bring information to you rather gloriously, there is something distinctly uncomfortable about content that continues over numerous links to pages of varying lengths. Anyone who has witnessed a slide show of a neighbor's family vacation can identify with the queasy sensation of boundlessness. Readers of electronic pages need tools to keep track of pages. The Netscape text fields, toolbar buttons, and menu items provide you with the ability to manage pages of information that might otherwise leave you feeling overwhelmed and unfocused. Each time you open the Netscape window (you can have multiple Netscape windows open concurrently), you begin a new session of Internet interaction. The author of a page supplies the content you initially see. Sometimes the content is presented as a single unit taking up the entire content area of the window. Other times the content is displayed in multiple rectangular frames that, together, form a patchwork of individual pages that fills the content area. Each frame can contain scroll bars to let you view more information. Netscape allows you to resize any frame by positioning the mouse in the borders between frames (the cursor changes shape), then dragging the frame to a new size.

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A frame within a page is, in essence, a smaller page within a large patchwork page. Each frame has characteristics of a page. Together, the frames form a top-level page (also called a frameset). For example, clicking on a link within a frame can bring new information within the frame or to a different frame. Likewise, a link can bring an entirely new top-level page replacing all the frames. When your link updates frames on a page, clicking the Back button returns the frame in its previous state. If you are viewing the original top-level frameset, clicking the Back button returns the previous whole page. When viewing a page with frames, certain menu items change to reflect that actions affect only a selected frame's page and not the set of pages in the top-level page. The Mail Document, Save as, and Print menu items change to Mail Frame, Save Frame as, and Print Frame, respectively. When you select a frame by clicking within it, other functions such as keyboard shortcuts affect only the contents of the frame. Some pages and frames have the capability to automatically update themselves. Pages that have server-push and clientpull capabilities contain instructions that allow multiple interactions with the server computers. You can always terminate these automatic actions by going to another page or otherwise exiting the page. To open a new Netscape window, choose the File|New Web Browser menu item. The new window brings another copy of your home page to screen in a fully functional and independent Netscape window. You can have simultaneous network connections. Knowing that every page has a unique URL To understand how a single page is kept distinct in a world of electronic pages, you should recognize its URL, short for Uniform Resource Locator. Every page has a unique URL just like every person has a unique palm print. (Arguments persist as to which is more cryptic.) Not only does each page have a unique URL, but also each image and frame on a page. You can access a page, an image, or an individual frame by supplying its URL. A URL is text used for identifying and addressing an item in a computer network. In short, a URL provides location information and Netscape displays a URL in the location field. Most often you don't need to know a page's URL because the location information is included as part of a highlighted link; Netscape already knows the URL when you click on highlighted text, press an arrow button, or select a menu item. But sometimes you won't have an automatic link and instead have only the text of the URL (perhaps from a friend or a newspaper article). Netscape gives you the opportunity to type a URL directly into the location text field (or the URL dialog box produced by the File|Open Location menu item. Using the URL, Netscape will bring you the specified page just as if you had clicked on an automatic link. Notice that the label on the location field says Location after you bring a page (or Netsite for pages from Netscape servers), or Go to as soon as you edit the field. As a shortcut, you can omit the prefix http:// and Netscape automatically uses full URL to complete the search.

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Here are some sample URLs: http://home.netscape.com/index.html ftp://ftp.netscape.com/pub/ news:news.announce.newusers On Windows, the location text field offers a pull-down menu to the right of the text. The menu contains up to 10 URLs of pages whose locations you've most recently typed into the field and viewed. Choosing a URL item from this menu brings the page to your screen again. The URLs are retained in the menu across your Netscape sessions. Netscape uses the URL text to find a particular item, such as a page, among all the computers connected to the Internet. Within the URL text are components that specify the protocol, server, and pathname of an item. Notice in the URL http://home.netscape.com/index.html that the protocol is followed by a colon (http:), the server is preceded by two slashes (//home.netscape.com), and each segment of the pathname (only one here) is preceded by a single slash (/index.html). The first component, the protocol, identifies a manner for interpreting computer information. Many Internet pages use HTTP (short for HyperText Transfer Protocol). Other common protocols you might come across include file (also known as ftp, which is short for File Transfer Protocol), news (the protocol used by Usenet news groups), and gopher (an alternative transfer protocol). The second component, the server, identifies the computer system that stores the information you seek (such as home.netscape.com). Each server on the Internet has a unique address name whose text refers to the organization maintaining the server. The last component, the pathname, identifies the location of an item on the server. For example, a pathname usually specifies the name of the file comprising the page (such as /welcome.html), possibly preceded by one or more directory names (folder names) that contain the file (such as /home/welcome.html). Some pathnames use special characters. If you are typing a URL into the location field, you'll need to enter the characters that exactly match the URL. For example, some pathnames contain the tilde character (~) which designates a particular home directory on a server.

Finding, Starting And Stopping Links A link is a connection from one page to another. You find a link by looking for one or more words highlighted with color, underlining, or both in the content area of a page. Images and icons with colored borders also serve as links. When the mouse cursor points over a link, the URL location of the link appears in the status field. A link within a page that contains frames can be a connection that brings one or more new pages within frames, or an entirely new top-level page replacing all frames.

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You can bring a linked page to your screen by clicking once on the highlighted text, image, or icon. Clicking on a link transfers page content from a server location to your location. After you click on a link, the Netscape status indicator animates to show you that the transfer of the page to your computer is in progress. You can stop a transfer in progress by pressing the Stop button or choosing the Go|Stop Loading menu item. An unfollowed link is a connection to a page that you have not yet viewed; a followed link is one you have. By default, unfollowed links are blue and followed links are purple. (On Windows and Macintosh, you can change the colors used to denote unfollowed and followed links from the Options|General|Colors menu item. On UNIX, modify your .Xdefaults file outside of the application.) If you have a black and white monitor, unfollowed and followed links are highlighted only with underlining and not differentiated. You can stop a transfer in progress whenever the transfer takes longer than you like. This might happen if the content of the page is large or if the server computer is sluggish. Sometimes the page specified by a link just isn't available. You'll usually get a message if a connection was not made or a page not found. Examine the status field and progress bar to receive feedback about the progress of a transfer. When you bring a page to your screen, you'll see the whole page or, if the content is extensive, only a portion. (Scroll bars let you see the rest.) Often the portion you see is the beginning of the page, but sometimes a link brings you content from the page's middle or end. A link can display a new page or display a different portion of the same page (in effect, automatically scrolling for you). For example, the beginning of a page might include a table of contents that links each chapter title to its respective content further down the page. Yet another kind of link doesn't bring a page at all. A mailto link whose URL begins with mailto:, produces the Message Composition window for sending email (with the recipient's address automatically filled in). Linking Via Buttons And Menu Items In addition to links in the content area, you can also access links using Netscape buttons and menu items. Many of the links controlled by buttons and menu items bring pages you have viewed at least once before. Button links are particularly useful for going back and forth among recently viewed pages. Menu item links directly access a wide range of pages such as a history list of pages you have viewed or a bookmark list of pages you (or others) have personally selected as noteworthy. The toolbar offers the following button links:

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Back displays the previous page in the history list. The history list is a reference to pages you have viewed.

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Forward displays the next page in the history list. (Available only after using the Back command or a history menu item.)

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Home displays the home page designated in your preferences.

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Open displays a dialog box where you can enter any URL.

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Once you have brought a page to screen, you can view (and store, if you wish) its URL. Every page is distinguished by its URL. Linking to a page via highlighted content, toolbar buttons, or menu items is a shortcut that enables you to display the page without having to explicitly request the page's URL. When no built-in link is available, you can display a page by entering the URL in the location field, then pressing the Enter (Return) key. (The label of the location field changes to Go to when you edit the field.) Alternatively, you can choose the File Open Location menu item, enter the URL in the dialog box, then press the Open button. Menu items offer each of the links available through toolbar buttons plus many more. The Netscape application keeps track of pages you have seen, lets you create easy-access lists of favorite pages, and points you to pages with current information about Netscape and the Internet. The page's title is displayed as the menu item.

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History items from the Go menu display previously viewed pages. The Netscape application automatically appends the title of a page you have viewed as the topmost menu item in the history list. The View History menu item shows you how the history lineage is maintained.

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Bookmark items from the Bookmarks menu display pages of your choice. You can add a bookmark menu item for the page you are viewing by choosing Bookmarks|Add Bookmark. The Window|Bookmarks menu item lets you establish lists of bookmarks for yourself and to share with others.

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Items from the Directory and Help menus display pages with up-to-date information on Netscape software and Internet exploration.

A pop-up menu offers utility features and a shortcut for certain links. On Windows and UNIX, you can click on the right mouse button to produce the pop-up menu (on Macintosh, press and hold down the mouse button). When the mouse button is pressed over a link or image, pop-up menu items let you go to pages, view individual images, save files onto your disk, copy locations to the clipboard, and perform other tasks. On the Windows 95 version, the pop-up menu item Internet Shortcut lets you create Internet shortcut icons that you can place on the desktop or in any folder. Clicking on an Internet shortcut icon automatically opens the Netscape application and loads a particular page. Using History And Bookmark Lists When you pull down a menu that contains history or bookmark items, you see a list of page titles. To bring a page to your screen, choose the title of the page. History items let you quickly retrieve pages that you've recently viewed in your current session. Only a single lineage of history items is displayed. For example, a series of pages containing maps might show you increasing detail as you click on links. If you view consecutively linked pages with titles North America, United States, Pennsylvania, and Philadelphia, you'll see all four items appear in the history list with Philadelphia topmost in the list. Furthermore, if you back up to the United States page, then view pages of California and San Francisco, California and San Francisco automatically replace Pennsylvania and Philadelphia. The new line of links replaces the old line of links.

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Bookmarks items offer a more permanent means of page retrieval. Once you add a bookmark to your list, the title stays until you remove it or change lists. The permanence and accessibility of bookmarks make them invaluable for personalizing your Internet access. Because bookmarks offer such ease of retrieval, the Netscape application offers many options for creating a bookmark list. Basic options let you add access to a page through a menu item. More advanced options let you create hierarchical menus, partial menu displays, multiple and shared bookmark files, list descriptions, and list searches. The Bookmarks window, displayed by choosing the Window|Bookmarks menu item, gives you tools to manage bookmark lists. These tools might differ slightly depending on the platform you are using. You'll find bookmarks and folders (a folder represents a hierarchical menu header) arranged like files and folders on your hard disk. You can double-click bookmarks to access pages, drag-and-drop icons to arrange your bookmarks, and use bookmark menu items to create new bookmark items and manipulate bookmark lists. For example, to create a hierarchical menu, choose Item|Insert Folder from the Bookmarks window, give the folder (header) a name in the dialog box, close the dialog, then drag a bookmark into the resulting folder. Don't let the advanced features dissuade you from the basic functionality of bookmarks. At its simplest, you can choose the Bookmarks|Add Bookmarks menu item to add the current page to your bookmark list, giving you direct access to your favorite pages. Choosing The Screen Look You can tailor the look of the Netscape application by showing or hiding certain graphical elements on the screen. You'll find the basic alternatives listed in the Options menu. The default settings show the toolbar, location field, and directory buttons. These graphical elements provide simplified access to links, commands, and page location information. By hiding any or all of these graphical elements, you increase the amount of screen real estate available for page content.

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Checking the Show Toolbar item displays a row of easily accessible buttons that substitute for widely used menu items.

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Checking the Show Location item displays URL information that's useful for tracking a page's whereabouts or requesting a new page.

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Checking the Show Directory Buttons item displays a row of handy buttons that substitute for some Directory and Help menu items.

Other items in the Options menu affect the presentation of information. Auto Load Images lets you designate whether to display inline graphics automatically. Document Encoding allows for the display of different language character sets.

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Choosing one of the preferences menu items General, Mail and News, Network, or Security produces a tabbed dialog box (or pop-up menu). Each preferences menu item provides access to specific preferences panels. The panels contain settings that determine how the Netscape application operates. Many settings affect the look of graphical elements and content. After you are finished changing any values, click the OK button to accept the new panel settings or click the Cancel button to close the dialog box without accepting changes. Changing Styles, Fonts, And Colors To see options affecting general styles, fonts, and colors, choose the Options|General menu item. The dialog box contains tabs to different panel settings. For options affecting the styles, font, and colors of mail and news, choose the Options|Mail and News menu item. In the General|Appearance panel, one set of radio buttons let you display the toolbar with Pictures, Text, or Pictures and Text. You can check whether to also underline colored links. With a black and white display, you must check this box to underline links so the links are visible. Another set of radio buttons lets you designate the number of days before the color of a followed link reverts back to the color of a unfollowed link. For example, if you specify 7 days, the color indicator for a followed link expires after 7 days and reverts to the unfollowed link color. If you choose Never, followed links never revert to the unfollowed color. Pressing the Now button causes all followed links to immediately revert to the color of unfollowed links. The default value specifies that followed links expire after 30 days. On Windows and Macintosh, you can select colors for links, text, and background in the Colors panel . Click the Custom check boxes, then press the Choose Color buttons (on Macintosh, click the colored boxes). If the check box is unchecked, default settings display unfollowed links in blue, followed links in purple, text in black, and background in white. For background, you can also choose an image file. On Windows and UNIX, the Images panel lets you choose how to display an image's colors to most closely match the computer's available colors. In the Fonts panel, a set of pull-down menus lets you choose the font and font size for each of the two types of fonts that pages use to display text: Proportional and Fixed. Most text uses a proportional font. Text in editable fields and certain paragraphs preformatted by the author of a page typically use a fixed font. Also in the Fonts panel, you can use the For the Encoding pull-down menu to choose the character set encoding that's associated with each proportional and fixed font pair. Netscape lets you choose encodings in order to accommodate the character symbols of numerous languages. You can view or modify the fonts associated with any encoding by choosing the encoding name from the menu, then choosing items from the proportional and fixed font pull-down menus. For example, for the default encoding Latin1, you can choose to display proportional font text in 12 point Times and fixed

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font text in 10 point Courier. Note that to apply a particular encoding to a page, choose from the Options|Document Encoding hierarchical menu. Selecting A Home Page You can designate your own home page (the page the Netscape application first brings to the screen each time you open a new window) by supplying a URL as a preferences panel item. The home page designated initially with Netscape software (the default) has this URL: http://home.netscape.com/index.html You can change your home page (and change back to the default) clicking the radio button Home Page Location in Options|General|Appearance, then typing the URL of the new home page you want. Alternatively, you can check the radio button Blank Page if you want the home page to be empty of content. Each time you ask the Netscape application to open a new window, the designated home page is brought to screen. The URL can designate a page from a remote computer or one on your hard disk. To get the URL of a page on your hard disk, choose File|Open File. Then select the page (file) on your hard disk (for example, you can choose your bookmarks file). After the page opens, you'll see its URL in the location field. You can select and copy the URL, then paste it into the Home Page Location text field in your preferences. At first, you probably won't have any pages stored on your hard disk. But later, you might want quick and sure access to certain pages, such as one with valuable links or one you've created for yourself. Viewing Inline Images Ideally, pages on the screen should present images (or other multimedia effects) as simply and efficiently as text. However, images (and sounds and movies) are relatively larger in byte size than text and can take considerable time to transport from remote computers (servers) to your computer. The length of time needed to bring a page with images depends on several factors, most prominently the speed of the modem or direct link connecting you with a remote server. To compensate for the potential lethargy of transmitting images, Netscape software offers features that let you manipulate how images are handled. The Netscape application loads images into pages automatically. If the author of a page has designed the page with inline images, the images are displayed when you bring the page to your screen. You have the option to turn off automatic image loading by unchecking the Options|Auto Load Images menu item. When this menu item is unchecked, the images in pages are replaced by small icons. In addition, the small replacement icon is sometimes accompanied by alternative text. Also called ALT text, alternative text is shown only as a substitution when an image is not loaded. On some platforms, ALT text is also shown temporarily within a rectangular border as an image is loading. You can view these images at a later time. To manually load all images that are represented by icons, you can press the Images button in the toolbar or select the View|Load Images menu item. To manually load an individual image, click on the image's icon.

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The advantage of unchecking Auto Load Images is that pages are brought to screen faster. The disadvantage is that you can't view the images until you specify that you want the images loaded. The Auto Load Images item affects subsequent links and not the current contents of a page. However, if you choose the View|Reload menu item or press the Reload button on the toolbar, you bring the current page back again, this time with the Auto Load Image option active. You also have the option of displaying an image incrementally as the image is transmitted or in a single burst after the transmission. Typically, the While Loading option provides more satisfying feedback. However, on a fast network, the After Loading option may complete the load slightly faster. To set this option, choose the Options|General|Images menu item, then select one of the two radio buttons: While Loading or After Loading. Like highlighted text, an inline image can be linked to another page, another position on the same page, or any type of external file such as an external image. As with all links, pointing the mouse button over a link puts the URL location of the prospective link in the status field. Viewing External Images External images (unlike inline images) are displayed in their own windows. You can view an external image by clicking on a link to the image. The Netscape application can open external images stored in GIF (Graphics Interchange Format), JPEG (Joint Photographic Experts Group), and XBM (X Bit Map) file formats. Other file formats require that you have a suitable helper application available on your hard disk (and referenced in the Helpers panel). Links to external images work like links to pages. An external image file has a unique URL just like an ordinary page. External images are not automatically loaded in their full representation even if the Auto Load Images item is checked. You can click on highlighted text, an image icon, or an inline image to bring an external image into a separate window on the screen. Netscape or the external application opens and presents the image in a separate window. You must click back into the Netscape window to continue working with the Netscape application. Pages that present large or detailed images often have inline snapshot images (also called thumbnail images) inserted into pages that serve as links to external images. Unlike the icon replacements, these snapshots provide an approximate view of the actual image, yet are still much smaller and faster to transport than the full image. You can expand the snapshot into the full image by clicking once on the snapshot.

Filling In Forms You can do more than read Netscape pages; you can write on them. Pages can contain forms for you to enter and send information. For example, a page might have a form with fields for you to enter a name and address next to a button

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that sends the information to the page's author. Forms can offer editable fields with or without default text, check boxes, radio buttons, pull-down menus, selection lists, and buttons to send or clear the information you enter. The content you enter into a form doesn't permanently alter the page (you don't modify the source page at its location), yet the form gives you the ability to conveniently transmit a response. To send ordinary email, you fill in fields to supply the content of your message, the subject summary, and the email address of the intended recipient. Pages with forms let you reply to information you read in the page. To send a form, you fill in one or more fields embedded within a page, usually labeled with instructions and configured with a button that sends the form's contents to the recipient without requiring you to provide any email address. The author of a page determines the layout of a form. A page can contain multiple forms, each form capable of sending fields independently of another form on the page. Fields in a form can restrict the kind or range of text you enter (such as numbers only) to help you fill in the form as desired. Typically, forms give you a fast and easy way to make a request or send back a response regarding the page you are reading. Forms can supply an interface to databases with fields that let you query for information and perform Internet searches. The Usenet news pages, designed for people to communicate with each other on special interests, contain forms for you to enter messages and subscribe to newsgroups. The Netscape software has built-in links to pages with forms for you to comment about the Netscape application, and request product information.

Setting Up Email And News This section gives you some background about Internet protocols and the preference items you use to set up your email and news services. Upcoming sections describe mail and news services in more detail. Before you can exchange email or access any newsgroup news, you need to tell the Netscape application how to make the appropriate connection to the server computer handling various protocol. Where your World Wide Web server uses uses the HTTP protocol to transport page information, your outgoing and incoming Internet mail servers use mail protocols (SMTP and POP3) and your Usenet news server uses a news protocol (NNTP). Do you know the name of your email servers and news server? If not, you will have to find out from your service provider, systems administrator, or resident know-it-all. After specifying the names of these servers as preference items in the Servers panel, Netscape software lets you send and receive email and newsgroup postings. Here are some of the preferences you can set in the Options|Mail and News panels.

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In the Servers panel, specify your mail server names in the Outgoing Mail (SMTP) Server field and the Incoming Mail (POP3) Server field. You should specify local mail servers, if available. Often, the same server name is appropriate for both fields and the name can be as simple as mail. You should also enter your email id (the part of your email address to the left of the @ symbol; not the entire address and without the @ symbol) in the POP User Name field.

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In the Servers panel, specify your news server name in the News (NNTP) Server field. You should specify a local news server, if available. Often, the name can be as simple as news.

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In the Identity panel, specify your name, email address (the entire address including the @ symbol), and your reply-to address (if you want mail replies sent to a different address than your email address) in the designated fields. This and other information provided in the panel establishes your identity to those who receive your mail and news messages.

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In the Organization panel, specify whether you want mail and news messages threaded and the method messages are sorted. By default, news messages are threaded and mail messages are not. When messages are threaded, replies are displayed adjacent to the original message and other replies to the original message. When messages are unthreaded (the box unchecked), replies are displayed according to the sorting order without regard to the position of the original message or other replies.

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In the Appearance panel, specify font characteristics of your message text and quoted text. By default, when you reply to a message, the original text is quoted (restated) with each line preceded by the > symbol. You can specify the style and size of the quoted text in your messages. You can also specify the layout of the window panes.

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In the Composition panel, specify whether you want your replies to automatically quote the original message, and whether you want a copy of your messages automatically sent to yourself, sent to another email address, or stored on a disk file.

Receiving And Sending Email To display the Mail window and access email features, choose Window|Netscape Mail. Or, as a shortcut, you can click on the mail icon (the small envelope in the bottom-right of the Netscape and News windows). When you open the Mail window, Netscape checks the server and retrieves any new mail. To receive mail, you'll have to enter your email password each session (or specify in the Mail and News|Organization panel that your password be remembered across sessions). After Netscape has initially checked the mail server for messages, Netscape can periodically recheck the server and inform you if any new messages have arrived. However, Netscape does not automatically retrieve these additional messages from the mail server. To retrieve new messages, press the Get Mail toolbar button or click the mail icon. A setting in the Mail and News|Servers panel determines how often Netscape automatically checks the mail server for new messages. You can also click on the mail icon from the Mail window to manually check the server and retrieve new messages. Netscape informs you of the availability of new messages using the mail icon.

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Before you've checked for mail (for example, before you've opened the Mail window or if you haven't supplied your password), you'll see a question mark (?) adjacent to the envelope. This indicates Netscape cannot automatically check the status of the mail server.

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After you've check for mail, you'll see the envelope alone. This indicates there are no new messages for you.

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Subsequently, when Netscape automatically checks the mail server and finds new messages for you, you'll see an exclamation point (!) adjacent to the envelope. This indicates that new messages are available for retrieval. On Macintosh, you'll also be notified of new messages by a mail icon flashing in the menu bar.

The Mail window contains three panes: a mailbox pane, a message header pane, and a message pane. Click on an item in the mailbox pane (such as the Inbox) to display the mailbox contents in the message header pane. Click on an item in the message header field to display the message contents in the message pane. Occasionally, you'll want to select multiple message headings, for example, to move messages to the trash. To select multiple, contiguous message headings, hold down the Shift key as you click on an item. To select multiple, noncontiguous message headings, hold down the Ctrl key as you click on an item. (On Macintosh, use the Shift key to select noncontiguous items). When two or more message headings are selected, the message pane is empty. The Mail window and the Message Composition window, described in subsequent sections, contain menu items, toolbar buttons, and clickable icons to let you compose, view, organize, store, and deliver your mail in varied ways. Menu items offer the full set of features. Toolbar buttons provide basic mail features such as getting mail, deleting mail, composing mail, replying to mail, and displaying your messages. Small, clickable icons in the message header pane let you highlight individual messages as read or unread, and flagged or unflagged. Using The Mail Window The mailbox pane and message header pane are organized in columns. Columns in the mailbox pane state a mail folder name, the number of unread messages it contains, and the total number of messages it contains. Columns in the message header pane state the sender name, its flagged status, its read status, the subject line, and date. You can resize panes by positioning your mouse between two panes (the cursor changes shape) and dragging. You can click on column titles in the message heading pane to temporarily rearrange items according to Sender, Subject, or Date. You can also use the View|Sort hierarchical menu to sort or thread messages so that replies are positioned adjacent to original messages. To arrange messages to your preferred criteria by default (that is, every time you open up the Mail window), you must set the preference items in the Mail and News|Organization panel. You can resize columns by positioning your mouse between two column headings (the cursor changes shape) and dragging. It's best to adjust the leftmost column first, because resizing a column repositions all the columns to the right. On UNIX, choose Options|Save Options to retain changes. Choose File|New Folder to display a dialog for creating a folder in the mailbox pane. You can drag messages from the message heading pane into a folder in the mailbox pane. Alternatively, you can select a message, then use the Message| Move hierarchical menu item to put a message into a folder. The Message|Copy item lets you put a copy of a message into a folder without moving the original.

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The Edit menu contains items for deleting selected messages and folders. Deleted items are put into a Trash folder. Choose Empty Trash Folder to permanently delete the contents of the trash. Here are other basic features you'll find in the Mail window:

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Searching in messages: Choose the Edit|Find menu item to search for text in the message header or content panes. When the first occurrence of matching text is found, the message is selected and displayed in the message field. Choose Edit|Find Again for additional occurrences.

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Email addresses: Choose Message|Add to Address Book to insert the address of the sender of the selected message into your Address Book.

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Marking messages: The Message menu also contains items that let you mark messages as read or unread, and flagged or unflagged. When you wish to mark or flag multiple selections, the menu item is more convenient than clicking on the small icons in the pane.

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Navigation: The Go menu contains items for navigating among adjacent messages, unread messages, and flagged messages.

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Viewing messages: The Options menu contains items that help determine the content of the message heading and message panes. You can specify that the message heading pane Show All Messages or Show Only Unread Messages. You can have header information displayed within each message by checking the Show All Headers item. Use the Document Encoding menu item if you wish to select alternative character sets. On Windows and Macintosh, menu changes are automatically preserved for subsequent sessions. On UNIX, choose Options|Save Options to preserve menu changes.

Using The Message Composition Window You create and send both email and newsgroup messages in the Message Composition window. Many different actions produce the Message Composition window and, when appropriate, the Netscape application fills in certain fields automatically. Sometimes you'll see highlighted links in the email and news messages you read. That's because the Netscape software automatically detects the text of a URL and converts the text to an HTML link. Any URL text you enter in the Message Composition window is automatically seen as a highlighted link by the recipient of your message.

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Choose the File|New Mail Message menu item to display the empty Message Composition window. The window has its own menu items, clickable buttons, and fields for your message's address, headings, and content. You can set which fields are visible by checking items in the View menu.

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Choose File|Mail Document (or File|Mail Frame) to display the Message Composition window with fields filled and the current page automatically attached. The Content field contains the current page's URL, the Subject field contains the page title, and the Attachment field displays the file name of the attached page.

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•

Choose a mail or news reply option to display the window with the address field filled in. You might also reply to pages and messages by clicking a mailto link or button.

Typically, you'll use the Send To field for the address of the primary recipient, the Cc field for additional recipients, the Subject field for briefly describing the message, and the Attachment field for including a page or disk file with the message. If you've specified a text file containing your signature in the Mail and News|Identity panel, your signature is appended to the message field in all of your mailings. You need to know the Internet mail address of where to send your email. Internet addresses typically contain a user name followed by the @ symbol (pronounced "at"), followed by mail server location name. For example, to send email to this company, enter [email protected]. You can create, edit, and store addresses, singly or in a folder list, in the Address Book window. Addresses are maintained in the Address Book window similarly to how bookmarks are maintained in the Bookmark window. Commonly, you'll send mail by replying to other mail. By default, the original text appears as quoted text (each line preceded by the > symbol), though you can turn this feature off in the Composition panel. You can also quote a message's text by choosing the Message Composition window's File|Include Original Text menu item or paste in a clipboard selection as quoted text by selecting Edit|Paste as Quotation. Pressing the Attach button produces a dialog box that lets you send email with a file attachment. An attachment is a separate document sent along with the email message. The dialog box buttons let you select a page URL or a file. You can choose to send a page as is (embedded with the HTML instructions that format Internet pages) or converted to plain text. After completing the dialog box (you can list multiple attachments), the attachment is ready to be sent along with your message. The Mail window offers options that let you send mail immediately or defer delivery. Typically, you'll want to send messages immediately if you're connected to the network. However, to reduce connection time, you can compose messages offline and defer sending mail until the next time you're connected. When the Mail window's Options|Immediate Delivery menu item is checked, the Message Composition window offers a Send Now toolbar button and menu item (Send button on Windows and UNIX). This allows messages you've written to be sent over the network immediately. Press the Send Now button or choose File|Send Now to transmit the message and any attachments to the recipient. When the Mail window's Options|Deferred Delivery menu item is checked, the Message Composition window offers a Send Later toolbar button and menu item (Send button on Windows; Later button on UNIX). This allows messages you've written to be stored in your Outbox folder (deferred) until you explicitly specify that the contents of the Outbox be sent. Press the Send Later button or choose File|Send Later to store the current message in the Outbox folder on your disk for transmission at a later time. Choose File|Send Mail in Outbox to distribute deferred messages.

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Receiving And Sending News To display the News window, choose Window|Netscape News. The News window operates similarly to the Mail window. If you skipped the previous pages on exchanging and composing mail, you might want to go back and read these now. Like mail, you create your news messages in the Message Composition window. People post messages (send their news) to newsgroups. Throughout the Internet, you'll find the newsgroup terms "message", "posting", and "article" used interchangeably. Newsgroups are organized by subject; each newsgroup has a name intended to reflect the topic of discussion for its messages. The Usenet is the collection of all newsgroups; it is the Internet's multifaceted bulletin board especially designed for people to communicate news with one another on special interest topics. The News window contains three panes: a newsgroup pane, a message header pane, and a message pane. Click on an item in the newsgroup pane to display a listing of messages in the message header pane. Click on an item in the message header field to display each message in the message pane. When you open the News window, the set of newsgroups you have specified in the Options menu is displayed in the newsgroup pane. You can choose the Show All Newsgroups menu item to see the broadest selection of available groups. However, the number of newsgroups is so large that you might prefer to limit your newsgroup pane to subscribed newsgroups. You can quickly access your favorite newsgroups without searching through the thousands of available groups by subscribing to newsgroups. The easiest way to subscribe to a newsgroup is to, first, display all newsgroups (choose Options|Show All Newsgroups) in the newsgroup pane, then locate each newsgroup you want ready access to and check the Subscribe check box beside the newsgroup name. After you subscribe to your favorite newsgroups, you can choose the Options|Show Subscribed Newsgroups or Options|Show Active Newsgroups menu item so that, each time you open the News window, the newsgroup pane displays only your chosen newsgroups. Active newsgroups are subscribed newsgroups that contain new messages. There are alternative ways to subscribe if you know a newsgroup's URL. Each of the following displays the newsgroup name in the newsgroup pane.

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Enter the newsgroup URL in the location field of the Netscape main window.

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Choose File|Add Newsgroup and type the newsgroup URL in a dialog box.

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Click on a link to a newsgroup or newsgroup message.

You still must check the Subscribe box if you want the newsgroup to be displayed in the pane in subsequent news sessions.

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Using The News Window The menu items, toolbar buttons, and clickable icons in the News window let you view and compose news messages in much the same way as you do mail messages. Here are the primary difference:

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Organizing messages: Typically, you'll organize and store your mail messages on your hard disk in folders you create. News messages, on the other hand, are already organized and stored in newsgroups on remote servers. If you want to store news messages on your hard disk, you'll need to explicitly save news messages using the File| Save As menu item. The News window does not offer a mailbox/folder facility.

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Multiple news hosts: You can have multiple news hosts (though most users only need and have one), each host supplying you with a set of newsgroups. Choose the File|Open News Host menu item to display a dialog box for specifying additional news hosts in your newsgroup pane.

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Replying to messages: The News window has a unique set of toolbar buttons that include variations on how you can reply to messages (also available through the Message menu). You can reply to news by sending a newsgroup message (Post Reply), an email message (Mail Reply), or both (Post and Mail Reply).

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Threaded messages: By default, newsgroup messages are threaded (replies are positioned adjacent to original messages). Toolbar buttons allow you to mark a thread or entire newsgroup as read. Like mail, you can click in the message header pane to change the read or flagged status of individual messages.

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Quantity and age of messages: Newsgroups often contain a large number of messages. Several commands help determine the quantity and age of messages that appear in the message header pane at a time. The default number of messages retrieved from the news server is set as a preference item in the Servers panel (maximum 3500). You can choose the File|Get More Messages menu item to display additional messages that do not exceed the maximum. From the Options menu, you can choose to Add from Newest Messages or Add from Oldest Messages to specify whether a batch of messages should begin with newer or older messages first. By default, newer messages are retrieved first.

•

Viewing messages: The Options menu lets you choose whether the message heading pane should Show All Messages or Show Only Unread Messages (the default). The default choice displays limits the message heading pane to displaying only messages you have not read.

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Email addresses: Like mail, you can choose Message|Add to Address Book to insert the email address of the news message sender into your address book.

Exploring Usenet News The URLs of Usenet news are formatted similarly, but not identically, to other pages. For example, the URL news:alt.tv.northern-exp specifies the server protocol news: and the newsgroup alt.tv.northern-exp. Unlike other Internet connections, the URL does not specify a server name and pathname with preceding slashes.

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Each newsgroup has a unique name, described with words separated by periods. Some words (like alt, short for alternative, or comp, short for computers) specify categories rather than a particular newsgroup. Note that not all news servers provide access to all newsgroups. Reading Usenet news can be as easy as reading any other Internet page: Click on a link and bring a Usenet news message to your screen. But newsgroup pages offer advantages (notably the ability to easily publish your own writing to other newsgroup readers) and disadvantages (no images, weak formatting, and limited links). Typically, each newsgroup presents its messages along threads. A thread bundles a message with a response to the message. The grouping of a new topic with one or more responses to the topic (in indented outline form) presents messages in a topical context. A strictly chronological organization of every newsgroup contribution would create a discombobulated trail of messages less pleasant than reading Joyce in his later years. When you subscribe to a newsgroup, the name of the newsgroup is added to a list (a News file; also called a News RC or newsrc file), maintained by the Netscape software. On Windows and UNIX, you can specify the location of your News file in the Servers panel. On Macintosh, the News file is stored in the Netscape folder within your system's Preferences folder. The process for retrieving information from news servers has a significant difference than the process for retrieving information from World Wide Web servers. News messages are collected and automatically distributed at periodic intervals, en masse, among news servers throughout the Usenet. When you supply a URL to request newsgroup messages, your request is routed to the news server provided by your service provider, which has accumulated messages throughout the Usenet system. In contrast, when you supply a URL to request a particular Web page, your request is routed to the single Web site whose server distributes the page. Likewise, a news message that you send goes to your service provider's news server, whereupon the message is automatically distributed at periodic intervals to other participating Usenet news servers. Other Usenet readers can then access your news message from their local news server. This batch processing of Usenet news permits distribution efficiencies. For example, a popular Web site can get inundated with requests for pages. However, a popular newsgroup is broadly distributed by the entire network of participating news servers. Your request for either Web pages or news messages contains some identifying information about the requesting computer. With Web pages, request information is conveyed to Web site that serves a page. With news, request information is conveyed to your provider's news server. Saving Pages Netscape software gives you the opportunity to save a page as a file on your computer. You can do this after or instead of bringing the page to your screen.

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Some links, for example those that transport software, sound, or movie files, don't transmit pages. You can often identify these links by noticing a URL that begins with ftp or ends with a file-type suffix such as au or mpeg. Clicking on these links can automatically download (save) a file to disk and launch helper applications that support the file's format. Most links, however, point to pages that you can bring to your screen or specifically save on your disk. The File|Save as menu item produces a dialog box that lets you save the current page as a source (HTML) file or a text file on your disk. (On UNIX, you can also save in PostScript format.) A file saved in HTML source format retains the formatting of the original page. A file saved in text format is presented as plain text. You can save an image file, but not a page's inline images. When you view a page containing frames, the File|Save Frame as menu item replaces File|Save as and lets you save only the page of a currently selected frame. The dialog box options for saving the page are unchanged. By using a pop-up menu item, you can save a page as a disk file instead of bringing the page to the screen. While pointing over a link, click on the right mouse button (on Macintosh, hold down the mouse button) to pop up the menu. The Save this Link as item saves to disk (instead of bringing to screen) the page whose link you are clicking on. The Save this Image as item saves to disk (instead of bringing to screen) the image whose link you are clicking on. Saving to disk is particularly useful for retrieving a nonformatted page (such as a data file) not intended for viewing. You can also produce the dialog box for saving a page to disk by clicking on a link with the Shift key held down (option key on Macintosh). Other pop-up menu items let you copy page and image locations (URLs) to the clipboard. After saving a file to disk, you can use the File|Open File menu item to display the local file as a Netscape page. (A file on your disk is a local file; a file out on the network is a remote file.) For GIF, JPEG, or other nontext files to appear as available files in the Open File dialog, make sure to select "All Files" as the file type (on Macintosh, hold down the Option key while selecting the Open File menu item). The View|Document Source menu item lets you view the current page in HTML source format. By default, source text is displayed in a window. On Windows and Macintosh, you can override the default source viewer by specifying a supporting text application (such as your word processor) in the View Source field of the General|Applications panel. Subsequently, when you choose View|Document Source, the HTML text appears in a window of your selected application. The File|Mail Document menu item produces a window that lets you send the current page URL along with an email attachment of the page. The Window|Bookmarks menu item produces a window that lets you save page links in a file. Note: Netscape software works on several computer platforms and reserves the use of a few special characters to help interpret URLs. To avoid problems, don't use the following characters when you create a file name:

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slash (/)

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colon (:)

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•

number symbol (#)

Printing And Finding Many of the File and Edit menu items in the Netscape application work as they do on other applications. To print the contents of the current page, choose File|Print or press the Print button in the toolbar. A Print dialog box lets you select printing options and begin printing. On Windows, you can choose File|Print Preview to see a screen display of a printed page. When you view a page containing frames, you'll see the File|Print Frame menu item in place of File|Print. The command lets you print only the page of a currently selected frame. The dialog box options for printing the page are unchanged. When printing a page, the Netscape application formats content according to the size of the printed page rather than the size of the onscreen window. The print command rearranges the page layout (text is wordwrapped and graphics are repositioned) in order to accommodate paper size. To set up the page for printing, choose File|Page Setup. You can use this command to choose landscape printing (across the long side of paper) instead of the more common portrait orientation. To cut, copy, and paste, choose the respective items from the Edit menu. Note that Cut and Paste items are only effective in certain editable fields. The content area is a read-only field that only enables you to select and copy text for use elsewhere. To find a word or phrase within a page, choose or press the Find button in the toolbar. A Find dialog box lets you enter the string of characters you wish to find. Check the Match case radio button (Case Sensitive on the Macintosh and UNIX) to require capital letters to match. On Windows, check the Up or Down radio button to direct the search toward the beginning or end of the document. If there is a current selection, the search begins at the selection and does not wrap around. On Macintosh and UNIX, check the Find Backwards check box to start the search from the beginning or end of the document. To find the same word or phrase again, choose Edit|Find Again. Identifying Secure Information Netscape software allows computers to transfer information in a secure way that prevents the forms you send or the pages you receive from being misappropriated. Security issues arise because information travelling on the Internet usually take a circuitous route through several intermediary computers to reach any destination computer. The actual route your information takes to reach its destination is not under your control.

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As your information travels on Internet computers, any intermediary computer has the potential to eavesdrop and make copies. An intermediary computer could even deceive you and exchange information with you by misrepresenting itself as your intended destination. These possibilities make the transfer of confidential information such as passwords or credit card numbers susceptible to abuse. The Netscape application and Netscape server use patented RSA public key cryptographic technology and custom software to allow you to send and receive information securely. The security protocols are open. Only your computer and the server can encrypt and decrypt your information. In transit, the information is an unreadable jumble. An intermediary can continue to route the data, and even make copies of it, but the information cannot be decrypted and remains private and safely communicated. As part of the cryptographic technology, the Netscape application and Netscape server are able to authenticate Internet servers. This prevents an intermediary computer from posing as your destination. Not all exchanges of information are secure. Netscape uses graphical elements and dialog boxes to inform you when you are interacting with secure and insecure server sites.

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A URL that begins with https:// (instead of http://) indicates that a document comes from a secure server. Similarly, a news URL that begins with snews: (instead of news:) indicates that a document comes from a secure news server. To access news servers other than the default news server, use two slashes (//) after the colon (:).

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To the left of the status message, a doorkey icon on a blue background indicates a secure document (a document is a slightly broader term for a page and its contents); a document with a broken doorkey icon on a gray background indicates an insecure document. Clicking on a doorkey icon displays information on the security status of a document.

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Above the content area, a blue colorbar indicates a secure document; a gray colorbar indicates an insecure document.

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Dialog boxes alert you to changes in security status among the documents you bring to screen. You can choose to bypass security dialogs by setting preference items in the Security|General panel.

You can examine the security qualifications of a document in more detail by choosing View|Document Info. The resulting dialog box tells you about encryption grade and server certification. You can view information about a particular site certificate or certificate authority in the Security|Site Certificate panel. Understanding Public Key Technology The public key technology working within the Netscape application and Netscape server is often described with unfamiliar security terminology. You might find the explanation of how public keys works an interesting supplement to your knowledge of Internet security.

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A computer's security key is a file. You don't open a key (file) like you open a document or a word processor application. Keys are more like magnetic badges with powerful encryption and decryption capabilities. There are two kinds of keys, private and public, and you need both. A private key sits on your computer and you never give it out. A public key you can make as many copies of it as you wish and give it out to everybody. You need both kinds of keys because they are fundamentally linked. (Like a pair of pants, you always buy both legs.) You can pass your public key around to whomever you wish, but in order for any key to perform its decryption duty, it must be matched back to its linked key partner. Both public and private keys have the ability to encrypt and (as a set) decrypt information. Keys work in two primary ways: 1.

Other users can encrypt information with your public key (the key you've distributed freely) and send the information securely to you. Only you, with your private key, can decrypt their message. The sender can be sure that the message is read only by you (encrypted for privacy) and has not been altered.

2.

You can encrypt information with your private key and send the information securely over the network. Anyone on the network who has your public key (the key you've distributed freely) can decrypt your message. The recipient can be sure that the message came only from you (authenticated with your digital signature) and has not be altered.

In summary, your public and private key (files) are linked by a powerful cryptographic algorithm that would require major computer resources to crack. No one else's keys can decipher messages to you encrypted with your public key. And no one else's keys can be used to pose as you by sending messages encrypted with your private key. Introduction To Electronic Commerce Defining E-Commerce E-commerce encompasses the entire online process of developing, marketing, selling, delivering, servicing, and paying for products and services purchased by inter-networked, global virtual communities of customers, with the support of a worldwide network of business partners. Electronic commerce systems rely on the resources of the Internet, intranets, extranets, and other computer networks to support every step of this process. For example, electronic commerce can include interactive marketing, ordering, and payment processes on the World Wide Web, extranet access of inventory databases by customers and suppliers, intranet access of customer records by sales reps and customer service, and involvement in product development via Internet newsgroups and E-mail exchanges. E-commerce is changing how companies do business both internally and externally with their customers, suppliers, and other business partners. How companies apply E-commerce to their business is also subject to change as their managers confront a variety of E-commerce alternatives. The applications of E-commerce by many companies have gone through several major stages as E-commerce matures in the world of business. For example, E-commerce between businesses and consumers (B2C) moved from merely offering multimedia company information at corporate websites (brochure ware), to offering products and services at Web storefront sites via electronic catalogs and online sales transactions. B2B E-commerce, on the other hand, started with website support to help business customers serve themselves, and then moved toward automating intranet and extranet procurement systems

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Electronic Data Interchange Data representing a variety of business transaction documents (such as purchase orders, invoices, requests for quotations, and shipping notices) are automatically exchanged between computers using standard document message formats. Typically, EDI software is used to convert a company's own document formats into standardized EDI formats as specified by various industry and international protocols. Thus, EDI is an example of the almost complete automation of an E-commerce supply chain process. And EDI over the Internet, using secure virtual private networks, is a growing B2B E-commerce application. The Internet, intranets, and extranets provide vital electronic commerce links between the components of a business and its customers, suppliers, and other business partners. There are three basic categories of electronic commerce applications:

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Business-to-Consumer (B2C)

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Business-to-Business (B2B)

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Consumer-to-consumer (C2C)

Business-to-Business E-Commerce This category of electronic commerce involves both electronic business marketplaces and direct market links between businesses. For example, many companies offer the business community a variety of marketing and product information on the World Wide Web. Others also rely on electronic data interchange (EDI) via the Internet or extranets for direct computer-to-computer exchange of business transaction documents with their business customers and suppliers. Business-to-business electronic commerce is the wholesale side of the commercial process. For example, let's suppose a company wants to build and sell a product to other businesses. Then it must buy raw materials and a variety of contracted services from other companies. The interrelationships with other businesses needed to build and sell a product make up a network of business relationships that is called the supply chain. Electronic commerce systems like electronic data inter- change (EDI), and business management processes like supplying chain management, seek to reengineer and streamline traditional supply chain processes.

Business-to-Consumer E-commerce E-commerce applications that focus on the consumer share an important goal: to attract potential buyers, transact goods and services, and build customer loyalty through individual courteous treatment and engaging community features.

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In this form of electronic commerce, businesses must develop attractive electronic marketplaces to entice and sell products and services to consumers. For example, companies may offer multimedia web sites that provide virtual storefronts and virtual shopping malls, interactive order processing, and secure electronic payment systems. Electronic commerce on the Internet between businesses and consumers is accelerating the impact of information technology on consumer behavior and business processes and markets. Technology is transforming consumer choices, which in turn transform the dynamics of the marketplace and organizations themselves. Technology embodies adaptability, programmability, flexibility, and other qualities so essential for customization. Together they have created the promise of "any thing, any way, any time". So the wide-open economic model of the Internet and the fast pace of change in Internet technologies are fundamental contributors to the development of electronic commerce applications between businesses and consumers. An example can be thought of retailing on web. Consumer-to-Consumer E-Commerce The huge success of online auctions like e-Bay, where consumers (as well as businesses) can buy and sell with each other in an auction process at an auction website, makes this E-commerce model an important E-commerce business strategy. Thus, participating in or sponsoring consumer or business auctions is an important E-commerce alternative for B2C or B2B E-commerce. Electronic personal advertising of products or services to buy or sell by consumers at electronic newspaper sites, consumer E-commerce portals, or personal websites is also an important form of C2C Ecommerce. Marketing Systems The business function of marketing is concerned with the planning, promotion, and sale of existing products in existing markets, and the development of new products and new markets to better serve present and potential customers. Thus, marketing performs a vital function in the operation of a business enterprise. Business firms have increasingly turned to computers to help them perform vital marketing functions in the face of the rapid changes of today's environment. Computers have been a catalyst in the development of marketing information systems that integrate the information flows required by many marketing activities. Interactive Marketing The explosive growth of the Internet has had a major impact on the marketing function. The term interactive marketing has been coined to describe a type of marketing that is based on using the Internet, extranets, and other networks to enable two-way interaction between a business and its customers or potential customers. The goal of interactive marketing is to enable a company to profitably use those networks to attract and keep customers who will become partners with the business in creating, purchasing, and improving products and services. The Internet has become the primary distribution channel of the new online marketing environment. Customers are not just passive participants who receive media advertising prior to purchase, but are actively engaged in a networkenabled proactive and interactive process.

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Interactive marketing views prospective customers as belonging to many distinct market segments that must be approached differently online. Interactive marketing also encourages customers to become involved in product development, delivery, and service issues. This is enabled by various Internet technologies, including Usenet discussion groups, Web forms and questionnaires, and E-mail correspondence. Finally, the expected outcomes of interactive marketing are a rich mixture of vital marketing data, new product ideas, volume sales, and strong customer relationships. Basics of HTML and DHTML What is the World Wide Web?

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The World Wide Web (WWW) is most often called the Web.

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The Web is a network of computers all over the world.

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All the computers in the Web can communicate with each other.

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All the computers use a communication standard called HTTP.

How does the WWW work?

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Web information is stored in documents called Web pages.

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Web pages are files stored on computers called Web servers.

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Computers reading the Web pages are called Web clients.

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Web clients view the pages with a program called a Web browser.

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Popular browsers are Internet Explorer and Netscape Navigator.

How does the browser fetch the pages?

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A browser fetches a Web page from a server by a request.

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A request is a standard HTTP request containing a page address.

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A page address looks like this: http://www.someone.com/page.htm.

How does the browser display the pages?

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All Web pages contain instructions for display

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The browser displays the page by reading these instructions.

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The most common display instructions are called HTML tags.

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HTML tags look like this

This is a Paragraph

.

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Who is making the Web standards?

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The Web standards are not made up by Netscape or Microsoft.

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The rule-making body of the Web is the W3C.

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W3C stands for the World Wide Web Consortium.

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W3C puts together specifications for Web standards.

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The most essential Web standards are HTML, CSS and XML.

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The latest HTML standard is XHTML 1.0.

REVIEW EXERCISE 1.

What is an internet .discuss its evolution

2.

Who maintains internet.how is it different from WWW.

3.

What are ISP’s.Name some ISP’s in India

4.

How does an E-mail function.Explain

5.

What is a URL.Explain with example

6.

What is a web-browser.How does it works.

7.

Explain the working of either internet explorer or netscape.Enumerating important features.

8.

What is meant by Hypertext links.

9.

What are usenet networks.Discuss their importance.

10. Differentiate between a home-page and a web-page. 11. Explain the importance of HTML. 12. Differentiate between host and terminal. 13. What do you understand by search engines.State their functions. 14. Explain the capabilities of Internet Explorer. 15. Discuss different types of internet accounts. 16. What is meant by mailing lists.How do these help. 17. Explain the advantages of mailing list. 18. How internet can be accessed in a LAN environment.Explain 19. Differentiate between a dial up and direct connection. 20. What are the various hardware and software requirements for a dial-up connection 21. What do you understand by terms uploading and downloading. 22. What does SLIP and PPP stand for.Explain 23. What are the different ways to access internet.Explain 24. What is internet telephony. Explain. Discuss advantages. 25. Discuss the business use of internet. 26. What do you understand by electronic commerce.Discuss the various types. 27. What is meant by interactive marketing. 28. What do you mean by web designing. 29. What is HTTP. Explain the working.

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30. What are the various types of lists in HTML. 31. How will you create hyperlink in HTML. 32. What are style sheets. Discuss the various types of style sheets. 33. Explain the difference between frame and frameset tags in HTML. 34. Explain the difference between HTML and DHTML. 35. How will you create a form in HTML.

UNIT II Intranet Internet is a series of interconnected networks whereas intranet can be simply defined as a private internet operating over an organisational internal network. An Intranet can do a lot for any organization. In fact, the potential for an intranet is limited only by the imaginations of the people in the organization who build, grow, and use it. From a broad perspective, though, everything an Intranet can do can be explained under two simple categories: The Intranet allows employees to use information technology they are using in their daily lives, and it provides all the benefits of any new technology.

•

An intranet can bring into an organization the same kinds of communication and information systems that employees use daily outside of their jobs. That is, the intranet can accommodate the expectations people increasingly have about how they get and use information.

•

An intranet can do what any technology can do-solve problems, improve processes, and open the door to new possibilities that the technology enables.

Consider e-mail as an example. In most organizations, systems departments set up e-mail without the collaboration of the departments or the employees who will be using it. These e-mail systems function precisely as they are supposed to. That is, they send information intact from the sender's workstation to one or more receivers' workstations. Still, many employees who have to use e-mail find it frustrating and annoying. They consider it, along with voice mail, a leading cause of information overload. Employees complain bitterly of overflowing in-boxes containing irrelevant messages. For any employee who travels on business, one of the worst parts of returning to the office is knowing that dozens of e-mail messages are waiting to be reviewed. True frustration sets in when only a small percentage of those email messages is aimed directly at the employee. The rest are •

Messages to all employees, or groups of employees, from other employees about nonbusiness topics (for example, "I lost my wrist watch.Did anybody find it?")

•

Messages to all employees, or groups of employees, about facility activities (for example, "The rear access door to Building 1 will be locked from 12:00 to 4:00 a.m. tonight for maintenance.")

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•

Messages about extracurricular activities (for example, "Who wants to go out for a party tonight. Other irrelevant messages that have little meaning to the employee and his or her job duties.

For many employees, the solution to this information overload is simply to delete all messages, which means they might delete important messages along with the garbage. But it's easier than spending hours out of a work day to separate the wheat from the chaff. In one organization I know, this situation was resolved not by the Systems Department that implemented the e-mail system, but by the Employee Communications Department, which existed prior to the implementation of e-mail but was not involved in the deployment of e-mail throughout the company. Employee Communications established a policy: All e-mail messages destined for distribution to all employees must be routed through the Employee Communications Department. Employee Communications does not censor the messages; nor do they rewrite or edit them. They simply gather one day's worth of such messages in a single e-mail message. The message begins with a list of the subjects of each e-mail message; thus, an employee can quickly scan the daily message for items of interest. The list might look like this:

1. 2. 3. 4. 5. 6.

TODAY'S ALL-EMPLOYEE MESSAGES Lost Wedding Ring After-Work Pizza Party Rear-Door Access Restrictions Quality Day Update Carpool Rider Needed Recycling Notice

If employees find something of interest, they can easily skip to it. If nothing appears interesting, they can delete the message without wasting any more time. And they know that the rest of the e-mail in their in-boxes is very likely meant specifically for them. That's a good solution, but the problem with it is that it is reactive. In other words, somebody had to come up with the solution to a problem that the e-mail system created. It would have been far better for the Systems Department to understand the information needs of the employee audience in the first place and design the system to prevent information overload. Working together, the Systems and Employee Communications departments might have arrived at the same solution before the e-mail system was unveiled, and there would have been no problems to solve. Intranets are no different. If you understand the way people expect to get and use information, and what the technology can do to meet those expectations, you are more likely to produce something that won't need to be fixed-or scrappedlater.

Building an Intranet That Meets Expectations The information revolution has arrived, and its effects can be seen everywhere. The workplace, however, has been slow to catch up with the rest of the world. Unfortunately, employees do not distinguish the workplace from the rest of the world. If information is only a keystroke away when they are in their living rooms or dens, why not from the computers on their desks at the office? If their children can study for tests or do research for their homework on the Internet, why can't employees do the same kind of research using information housed in company computers? If bank balances are available by touching a few pads on a telephone, why isn't work-related information as accessible?

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There are three main reasons why companies need to provide information systems that accommodate the changes that are taking place around the world and throughout cultures in how information is presented and used: 1.

To compete for the most talented workers

2.

To maintain a flexible workforce

3.

To acknowledge that the models of communication are changing as a result of the information revolution

Intranets provide an enterprise portal for applications in communication and collaboration, business operations and management, web publishing and intranet portal management.

Advantages of an Intranet: The Competitive Advantage Ask any human resources manager to define the primary role of the human resources department, and you're likely to get an answer that sounds a lot like, "To attract and retain the best employees." Companies consider many factors in their efforts to attract employees, including salary, benefits, Business Operations andlocation, career advancement potential, and the work environment.

Existing Databases and Enterprise Application

Everyone

Management

Secure Universal access to view and use corporate and and decide accordingly take effective decisions. externali.e data

Intranet

Intranet gives you competitive advantage as you are able to shareIntranet information at a much faster pace

F I R Students use e-mail, Gopher, the World Wide Web, and other online tools to do their day-to-day work. Many E even turn to the World Wide Web and sites such as CareerMosaic to facilitate their job hunts. To force these graduates W to abandon A to give up these tools in favor of memos, voice mail, faxes, and other older tools would be like asking graphic designers Web Publishing L their design programs and return to X-Acto knives, waxers, and parallel rulers! Employees L HTML,So,MS Office, given a number of job offers in which all otherand elements are roughly equal, a candidate is likely to accept the Author, publish share Extranet XML, Java and Other hypermedia documents position that provides the same tools he or she grew accustomed to using in school. The companies that offer these Document Types Customers, Suppliers tools-many of which are built into the intranet-will acquire the best talent. and Partners The Workforce AdvantageInternet

Enterprise Portal

Portal Management

At a time when companies are trying to shrink their way to success through downsizing, layoffs, reengineering, and other activities that lead to reductions in theadminister employee ranks, many employees are looking for signs that the company is Centrally clients, Existing Hardware doing something to help keepservers, them fromsecurity, becomingdirectory, unnecessaryand in the organization. As organizations begin to use new and Networks traffic and communicating, those employees who resist them are likely to become systems for information processing redundant. A company can, therefore, make a strong case that implementing intranets is a way for all employees to learn a new skill that will become vital in the very near future, helping to ensure their employability. (Of course, organizations also will need to offer training and other tools to help employees make the shift.) if employees learn to use intranets, they will have at their command a working knowledge of how to use the most modern and exciting of technologies in every aspect of their work.

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The Timeliness Advantage Employee communication audits conducted in companies large and small, in North America and around the world, all indicate the same problem. Employees want information sooner. Nothing drives an employee crazier than learning about an action the organization has taken by hearing it on the nightly news or-worse-from a neighbor or friend who has already heard it! NOTE With an intranet, organizations can provide information in the timeliest possible manner. Information that must, under Securities and Exchange Commission regulations, be disclosed to financial communities before it is communicated internally can, thanks to the Intranet, be delivered to employees simultaneously. Breaking news also can be delivered to employees before they hear it elsewhere.

The Data Advantage Companies maintain vast volumes of information in their databases, but most employees have no idea how to access it. Intranets offer employees a simple-to-use interface that allows them to get at data within any database the organization wants to make available, anytime and from anywhere. For example, employees can identify items in inventory and obtain other data that can serve customers calling for information on their accounts. NOTE To young people, a computer, along with its online communication, is not technology-it's furniture. Access to data increases employees' ability to perform their jobs faster, move accurately, and with confidence that they have the right information. With an intranet, employees can manage their own personnel information, reducing data-entry requirements. Additionally, human resources can add and delete employees and update their files using the same interface they use for other communications and information-gathering activities-the Intranet. The Communication Advantage The application of technology to communication and information has invaded every corner of our lives, and employees are living through the transformation, experiencing it, and coming out of it with expectations about how information is made available, how they can access it, and how they can interact with it. Companies and organizations that do not accommodate these changes are at risk.

NOTE The explosive growth of the Internet demonstrates that people- people who are likely to be your employees- are embracing the new ways to communicate and obtain information. Employees who have easy access to information everywhere except at work can grow frustrated. They can begin to perceive the organization as old-fashioned, restrictive, unable to keep up with the rest of the world. The best of those employees may well leave the organization to pursue opportunities with other organizations-including competitors- that "get it." Thus, companies that do not embrace the new models of communication could wind up with a workforce mired in mediocrity, since they cannot attract new employees or retain the best of those they already have.

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Changing Communication Models Out in the world, there are four models of communication that are changing: many-to-many, receiver-based, accessdriven, and communications based on demographics. Many-to-Many Communications We have been living in a "few-to-many" world, in which those who can afford to, publish information that is distributed to everyone else. The information age is changing this age-old few-to-many model to a new, "many-to-many" model. Since anybody can publish now, people are no longer limited to the traditional media for the information they need. They can turn, instead, to one another. Increasingly, that's exactly what they are doing. NOTE The World Wide Web and USENET newsgroups are two methods by which many-to-many communication works. The World Wide Web is primarily a publication medium: Web site hosts develop their pages and post them on servers where clients can request them for viewing. Interactivity is, of course, a key characteristic of the World Wide Web, but generally, senders provide information to a receiver who absorbs the information to do with as he or she pleases. The principal change from traditional publishing is that anybody can put up a Web page. The traditional media have invested awesome sums of money to develop sites on the World Wide Web. Over 500 daily newspapers have established Web sites, as have most of the major national news outlets (such as CNN, the major television networks, Time magazine, and the like). Corporations that have sunk millions into traditional advertising have turned to the Web as a new venue. Yet these do not necessarily represent the most successful Web sites. The ease with which people can publish provides audiences with a wealth of information and ends their reliance on the traditional media as their only source of information. People can elect to listen to, for example, NBC's nightly news story about a particular subject, then surf the Web in search of additional (or contradictory) information. Or they can choose to bypass the traditional media altogether, getting information directly from the sources they learn to trust online. Despite the visibility of the World Wide Web, USENET newsgroups are where much of the significant many-to-many communication shift is taking place. It is in newsgroups (and their counterparts on BBSs and commercial online services) that the power of distributed, networked communication is most evident. It is easy-and getting easier-to find information from people who have it, as opposed to relying on the traditional media. The difference between getting information from traditional media and getting it from people who are actually involved in the issue you are interested in is the difference between viewing a map and being on the landscape. NOTE As you can see, many-to-many communications have obvious advantages, providing people with the ability to tap into resources far beyond those which were available before. Regardless of where they are in the world, in what time zone, and despite having never met one another, people with mutual interests can share experiences and knowledge.

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Challenges also accompany many-to-many communications. The same abilities allow individuals to organize into activist groups overnight, whereas this type of organizational effort once took months and even years. It allows unpopular viewpoints to have the same exposure as credible, well-researched opinions.

Applying Many-to-Many Communications through an Intranet Inside the workplace, however, without the benefit of an intranet designed to meet their needs, employees are frustrated in attempting to use similar tools as they approach their jobs. Without these tools, employees are limited to old-fashioned methods of getting information. If they need design specifications for a certain product, they must make a phone call to the right person in order to process a request. If they have a question about how to perform a certain function-say, an engineering task-they are limited to asking only those individuals they already know, usually those whom they see on a daily basis. With an intranet, on the other hand, employees can •

Engage in newsgroup-like discussions that are based on topics of common interest

•

Create Web pages that offer information on topics of specific interest and then make the pages available for other employees who may need that information

•

Find information published by others when they need it

Receiver-Based Communications In the emerging information economy, people want "what they want when they want it." Unfortunately, the common method of delivering information is to give them "what we've got when we get it to them." In most cases, the material presented to audiences is linear (it must be absorbed from beginning to end) and produced from the point of view of the sender. Traditional communication must be absorbed from front to back, from chapter one to chapter two, from page one to page two, from paragraph one to paragraph two, and so on. If individuals need specific information that is buried somewhere within the document, they will have a hard time finding it, and if they do, it will be completely out of context. Furthermore, these communications are invariably written from the point of view of the sender. If you have ever received an employee-benefits handbook, you know what I'm talking about. The benefits department almost always bases the handbook on plans. There are health plans, life insurance plans, and disability plans. Under health plans you find medical insurance, dental insurance, and vision insurance. Under medical insurance you can find indemnity plans, preferred provider organizations, health maintenance organizations, and managed care plans. If you need to find out what coverage you have if your child breaks her arm, you are still limited to finding the appropriate information from within the maze of plan-based information. The World Wide Web is one example of receiver-driven communication. Using search engines and hyperlinks, individuals can find precisely what they are looking for. Most information presented on the Web is based on the usefulness of the information on the individual page; you can start in the middle.

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NOTE Receiver-based communications presume that the receiver will be able to "pull" the information he or she wants rather than have the sender "push" the information. For example, I recently needed to find the appropriate write up on IPV6 protocol A search on the search engine AltaVista took me directly to the page that contained the procedure; I did not need to start with a table of contents or an index. News groups are other examples of this mode. Receiver-driven communication also allows the users of information to customize the data they receive. Here are some examples of customized information: •

InfoSeek recently unveiled a hybrid of a news service and a search engine called InfoSeek Personal. It uses profiles to create hyperlinks from key categories (news and sports, for example) to specific items that meet subscribers' information needs.

Applying Receiver-Based Communications through an Intranet In a custom-built information environment, the traditional information "gatekeepers" have dramatically less influence than they had in the past. When you customize your information, if employees don't want to know anything about a specific issue-such as developments in an international hot spot or an update of the company's strategy-they don't have to. That presents a new challenge to those who are charged with ensuring that appropriate audiences receive key information. That, of course, is what an intranet is all about! All of the information stored in a company's computer memory banks, all of the intellectual capital stored in the heads of the organization's employees, and all of the knowledge developed by each department of the company can be made accessible without the employee ever having to leave his or her desk, find and complete a form, or make a phone call. At National Semiconductor, for example, employees can tap into the "Communities of Practice." Here, they can quickly drill through discussions employees have already had online to learn whether information they need has already been addressed. If they find that it has, they can identify other employees who have insight into the topic and either send email or even pick up the phone and call. (It's less technological but very efficient anyway!) Access-Driven Communications Communication technology makes it possible for receivers of information to get what they want when they want it. An example of providing access to information that most of us already take for granted is Interactive Voice Response (IVR)- a telephone technology that people use to retrieve information by simply pressing numbers on a telephone keypad. Odds are, this isn't a new concept for most readers; you probably use IVR routinely. For example, what do you do when you need to know your bank account balance? Before information became access driven, you waited for your monthly statement to arrive in the mail, by which time the balance listed was several days old. Now, you simply dial your bank's phone number, enter your account number and a personal identification number, and hear your balance as of the close of business the previous day.

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You probably also use IVR to find the movies that are playing nearby, to check and manipulate the investment balances in your employee savings plan, and to get directions to civic buildings. IVR is access driven because everyone has a phone, or access to one! Interactive touch-screen technology is another example of access-driven communications. More and more, touchscreens are showing up in medical centers, shopping centers, and high-rise buildings. Users who need information simply walk up to the screen and get what they need. For those individuals with computers and Internet connections, the World Wide Web provides access-driven information. Applying Access-Driven Communications through an Intranet Just as with many-to-many communications, organizations need to figure out ways to provide access to the information employees need to do their jobs, because they are growing more and more comfortable with accessing information of every other kind for their nonwork-related activities. The factory floor provides an ideal example of providing access to information via an intranet. Employees working on the line can go to a kiosk and quickly find the latest specifications for a product they are required to produce, tracking the updated information provided by the engineers who produce the specifications. It's much faster than trying to get in touch with the engineers directly-they may work in a different time zone-and much more likely that the project will be up and running according to schedule. Another example: The employee magazine carried an article two years ago that answers all the questions an employee may have about a particular topic. The employee who needs the information, though, may not have kept all his or her back issues of the magazine. If he or she did, it would be time-consuming to try to find the right article. Perhaps the employee did not work for the company two years ago and does not know the article appeared. A search of the intranet, however, makes all the articles ever published in the company magazine instantly accessible, and produces the one that meets the employee's search criteria.

Doing What Technology Does Best It is common for somebody who is close to a subject to become enraptured by the tactics of his or her interest and lose sight of the bigger picture. A human resources manager can get excited about a new program or benefit that will not fit right in the organization. A communicator can become enamored of expensive print production advances even though there is no place for an expensive magazine in the company. A finance executive can get excited about the prospect of managing the company by using shareholder value as the linchpin, even though shareholder value might not be the best way to evaluate performance. An Intranet offers the same trap to systems professionals, who may be inclined to recommend that an intranet do one thing or another simply because it can, because the technology makes it possible, and to do so would be fun; it would be cool. In the end, though, there are only three conditions under which an organization should consider investing in technology: •

To solve a problem

•

To improve a process

•

To do something the organization has never before been able to do

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The intranet offers spectacular opportunities to accomplish each of these conditions. Implementing An Intranet Once we have already network in place the following are the steps for implementing an intranet Planning: how our intranet finally evolves depend on how well we plan it the following are certain important concerns while drawing an effective plan for intranet: •

What do we want to make intranet available on the intranet

•

Do we want to give personal home pages?

•

Who will administer site?

•

How should the pages lay-out look like?

•

What Internet connection we will use.

•

Would we be connecting just for mail or would we be using other internet goodies like browsing the web, newsgroups etc?

Developing Interface And Security Security and privacy is one of the most important benefits of the intranet. We have to decide the clients to whom we would like to grant access to get on our intranet we may want to give access to every one from beginning or we may want first stablise the system with a basic set-up running and then grant access to others work-out or sub nets if required and our IP addressing plan if we have large number of nodes and servers this can became a very major and time consuming exercise. Hardware and software selection: decide on our server platform and the software that we will use to run our web and mail servers. Ensure the front-end software like browser and mail.The server machine for our intranet will depend on size of our network and number of nodes we want to add also identify the other servers as well as client nodes to be added to the intranet Operating system Install intranet server on the server platform. A web server and a mail server are essential for the implementation of the intranet. Add features and values Add features like discussion forums,a mailing list server, ftp server,html editors etc. Training Provide training to the people on how to use intranet. Applications of the Intranet Video-Conferencing The videoconferencing over the intranet requires a desktop, a camera and a microphone at its respective sites. This attempt of video-conferencing saves huge cost as compared to the traditional video-conferencing.

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One-to-one communication:one-to-one communication is also one of the advantages as well as an application. The opportunities for cost savings in the area of human resource management are numerous, an intranet can provide employee service such as getting information on benefits, holiday sick leaves, job posting and training. Intranet serves as an exellent cost saving device when used for employee corporate communication. Group discussion: Tools like news groups and e-mail groups may be established using the intranet allowing employees to communicate with one another on a large scale than e-mail using the many to many approach employee may form groups on a host of subject ranging from research and development, training, product packaging etc. On-line electronic forms: on- line electronic from filling is one of the very attractive and wonderful activity which leads to higher productivity besides being a very fast activity this activity adds to cost reduction. Using this application company can survey their employee over intranet.

•

Telecommuting: Telecommuting on extended intranets offers work at home opportunities for all workers. Organization can save relocation cost by employing workers where they curently live.

Other application of intranet include •

Research and development

•

Sales and marketing application

•

Extending the intranet to consumers and suppliers

•

Electronic Commerce

•

Real time audio and video communication

•

Live and recorded audio and video presentation on demand

•

Customized orders on demand

•

Database and legacy application access

•

Information publishing and sharing

•

Searching data-base through intranet

•

Application software on demand

•

Directory of people and resources

•

Human resources applications

•

Financial applications

•

Financial trading

Benefits of an Intranet •

Increased efficiency and effectiveness

•

Rapid deployment

•

Low learning curve

•

Lower cost to supply chain management

•

Investment protection on existing infrastructure

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•

Inter-operability at the network level

•

Improved relationship with customer and suppliers

•

Centralised management

•

Low cost of implementation

•

Open standards and flexibility

•

Fast and effective communication

How To Make A Successful Intranet Though the intranet is spreading its wings in all walks of life due to multi-benefits in the organization. We must understand and accept some important ingredients to make intranet a grand success in our organization. These are discussed in short below:

1.

Team work: unless the culture of team work is not developed it is very difficult to make intranet a grand success. A robust intranet requires active and continual participation from all department and divisions.Each user and group has to maintain its own content and needs to update it regularly.

2.

Openness and Sharing: what we put on intranet is there for every one in the organisation to see except personal mails but discussion forums, bulletin boards and web pages are there for all to see, comment upon and criticize hence, it requires a fair degree of openness within the organisation to make the intranet succeed:

3.

Trust: The important information presented via intranet needs to be trusted as there is no signature of authentication hence, trust automatically becomes a vital component in making intranet a success.

4.

Follow Standards: computers should use software with some bare minimum capabilities and at least productivity tools like word-processors and spreadsheets The persons working should be aware of working on internet.

Summary An Intranet is hardware and software; it is a mirror of the Internet that exists within your organization, allowing systems to expand in the same type of open environment as the Internet. But an intranet is far more than just the configuration of hardware and software that makes it work. It is a system by which real people produce, find, and use information. It is a system that enables people to do their jobs better and faster. It is a system that makes it easier to engage in the day-to-day tasks at work. Systems professionals need to understand why an intranet is a good idea before rushing off to build one. When they understand this, they can build an Intranet that works-that meets the real needs of real employees. An intranet is a good idea because: 1.

It allows employees to deal with information inside the company in the same way in which they are becoming accustomed to dealing with information everywhere else.

2.

It solves problems, improves processes, and allows organizations to use information to achieve results that otherwise would not have been possible.

What is an HTML File?

•

HTML stands for Hyper Text Markup Language

•

An HTML file is a text file containing small markup tags

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•

The markup tags tell the Web browser how to display the page

•

An HTML file must have an htm or html file extension

•

An HTML file can be created using a simple text editor

Do You Want to Try It? If you are running Windows, start Notepad (or start SimpleText if you are on a Mac) and type in the following text:

This is my first homepage. This text is bold Save the file as "mypage.htm". Start your Internet browser. Select "Open" (or "Open Page") in the File menu of your browser. A dialog box will appear. Select "Browse" (or "Choose File") and locate the HTML file you just created - "mypage.htm" - select it and click "Open". Now you should see an address in the dialog box, for example "C:\MyDocuments\mypage.htm". Click OK, and the browser will display the page. Example Explained The first tag in your HTML document is . This tag tells your browser that this is the start of an HTML document. The last tag in your document is . This tag tells your browser that this is the end of the HTML document. The text between the tag and the tag is header information. Header information is not displayed in the browser window. The text between the This is my first homepage. This text is bold

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This is an HTML element:

This text is bold The The

HTML content

element

starts

with

the

HTML

element

of

a is:

start This

tag: text

is

bold

The HTML element ends with an end tag: The purpose of the tag is to define an HTML element that should be displayed as bold. This is also an HTML element:

This is my first homepage. This text is bold This HTML element starts with the start tag , and ends with the end tag . The purpose of the tag is to define the HTML element that contains the body of the HTML document. Why do We Use Lowercase Tags? We have just said that HTML tags are not case sensitive: means the same as . When you surf the Web, you will notice that most tutorials use uppercase HTML tags in their examples. We always use lowercase tags. Why? If you want to prepare yourself for the next generations of HTML you should start using lowercase tags. The World Wide Web Consortium (W3C) recommends lowercase tags in their HTML 4 recommendation, and XHTML (the next generation HTML) demands lowercase tags. Tag Attributes Tags can have attributes. Attributes can provide additional information about the HTML elements on your page. This tag defines the body element of your HTML page: . With an added bgcolor attribute, you can tell the browser that the background color of your page should be red, like this: .

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This tag defines an HTML table: . With an added border attribute, you can tell the browser that the table should have no borders: Attributes always come in name/value pairs like this: name="value". Attributes are always added to the start tag of an HTML element. Quote Styles, "red" or 'red'? Attribute values should always be enclosed in quotes. Double style quotes are the most common, but single style quotes are also allowed. In some rare situations, like when the attribute value itself contains quotes, it is necessary to use single quotes: name='John "ShotGun" Nelson' The most important tags in HTML are tags that define headings, paragraphs and line breaks. Try it Yourself - Examples A

very

simple

HTML

This example is a very simple HTML document, with only a minimum of HTML tags. It demonstrates ho

The content of the body element is displayed in your browser. w the text inside a body element is displayed in the browser. The content of the body element is displayed in your browser. Simple paragraphs This example demonstrates how the text inside paragraph elements is displayed in the browser.

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document

This is a paragraph.

This is a paragraph.

This is a paragraph.

Paragraph elements are defined by the p tag.

This is a paragraph. This is a paragraph. This is a paragraph. Paragraph elements are defined by the p tag. Headings Headings are defined with the

to

tags.

defines the largest heading.

defines the smallest heading.

This is a heading

This is a heading

This is a heading

This is a heading

This is a heading

This is a heading

HTML automatically adds an extra blank line before and after a heading. Paragraphs Paragraphs are defined with the

tag.

This is a paragraph

This is another paragraph

HTML automatically adds an extra blank line before and after a paragraph.

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Line Breaks The
tag is used when you want to end a line, but don't want to start a new paragraph. The
tag forces a line break wherever you place it.

This
is a para
graph with line breaks

The
tag is an empty tag. It has no closing tag. Comments in HTML The comment tag is used to insert a comment in the HTML source code. The browser will ignore a comment. You can use comments to explain your code, which can help you when you edit the source code at a later date.

Note that you need an exclamation point after the opening bracket, but not before the closing bracket. Basic Notes - Useful Tips When you write HTML text, you can never be sure how the text is displayed in another browser. Some people have large computer displays, some have small. The text will be reformatted every time the user resizes his window. Never try to format the text in your editor by adding empty lines and spaces to the text. HTML will truncate the spaces in your text. Any number of spaces count as one. Some extra information: In HTML a new line counts as one space. Using empty paragraphs

to insert blank lines is a bad habit. Use the
tag instead. (But don't use the
tag to create lists. Wait until you have learned about HTML lists.) You might have noticed that paragraphs can be written without the closing tag

. Don't rely on it. The next version of HTML will not allow you to skip ANY closing tags. HTML automatically adds an extra blank line before and after some elements, like before and after a paragraph, and before and after a heading. We use a horizontal rule (the

---

tag), to separate the sections in our tutorials.

More Examples Line

Breaks

This example demonstrates the use of line breaks in an HTML document.

101

To break
lines
in a
paragraph,
use the br tag.

To break lines in a paragraph,use the br tag. Background

Color

This example demonstrates adding a background-color to an HTML page.

Look: Colored Background!

Adding image in the background

Look: A background image!

Both gif and jpg files can be used as HTML backgrounds.

If the image is smaller than the page, the image will repeat itself.

102

Basic HTML Tags Tag

Description



Defines an HTML document



Defines the document's body

to

Defines header 1 to header 6

Defines a paragraph




Inserts a single line break

---

Defines a horizontal rule



Defines a comment

HTML defines a lot of elements for formatting output, like bold or italic text. Below are a lot of examples that you can try out yourself:

Examples Text

formatting

This example demonstrates how you can format text in an HTML document. This text is bold
<strong> This text is strong
This text is big

103


<em> This text is emphasized
This text is italic
<small> This text is small
This text contains <sub> subscript
This text contains <sup> superscript

104

This

text

is

bold

This

text

is

strong

This

text

is

big

This

text

is

emphasized

This

text

is

italic

This

text

is

small

text

contains

This This text contains

subscript

superscript

How to View HTML Source Have you ever seen a Web page and wondered "How do they do that?" To find out, simply click on the VIEW option in your browsers toolbar and select SOURCE or PAGE SOURCE. This will open a window that shows you the actual HTML of the page. Text Formatting Tags Tag

Description



Defines bold text



Defines big text

<em>

Defines emphasized text



Defines italic text

<small>

Defines small text

<strong>

Defines strong text

<sub>

Defines subscripted text

<sup>

Defines superscripted text



Defines inserted text

<del>

Defines deleted text

<s>

Deprecated. Use <del> instead

<strike>

Deprecated. Use <del> instead



Deprecated. Use styles instead

"Computer Output" Tags Tag

Description



Defines computer code text



Defines keyboard text

<samp>

Defines sample computer code



Defines teletype text

105



Defines a variable

<pre>

Defines preformatted text

<listing>

Deprecated. Use <pre> instead

<br /> <br /> Deprecated. Use &lt;pre> instead<br /> <br /> &lt;xmp><br /> <br /> Deprecated. Use &lt;pre> instead<br /> <br /> Citations, Quotations, and Definition Tags Tag<br /> <br /> Description<br /> <br /> <abbr rel="nofollow"><br /> <br /> Defines an abbreviation<br /> <br /> <acronym rel="nofollow"><br /> <br /> Defines an acronym<br /> <br /> <address rel="nofollow"><br /> <br /> Defines an address element<br /> <br /> <bdo><br /> <br /> Defines the text direction<br /> <br /> <blockquote><br /> <br /> Defines a long quotation<br /> <br /> <q><br /> <br /> Defines a short quotation<br /> <br /> <cite><br /> <br /> Defines a citation<br /> <br /> <dfn><br /> <br /> Defines a definition term<br /> <br /> Some characters like the < character, have a special meaning in HTML, and therefore cannot be used in the text. To display a less than sign (<) in HTML, we have to use a character entity. Character Entities Some characters have a special meaning in HTML, like the less than sign (<) that defines the start of an HTML tag. If we want the browser to actually display these characters we must insert character entities in the HTML source. A character entity has three parts: an ampersand (&), an entity name or a # and an entity number, and finally a semicolon (;). To display a less than sign in an HTML document we must write: &lt; or &#60; The advantage of using a name instead of a number is that a name is easier to remember. The disadvantage is that not all browsers support the newest entity names, while the support for entity numbers is very good in almost all browsers. Note that the entities are case sensitive. This example lets you experiment with character entities: Character Entities Non-Breaking Space The most common character entity in HTML is the non-breaking space. Normally HTML will truncate spaces in your text. If you write 10 spaces in your text HTML will remove 9 of them. To add spaces to your text, use the &nbsp; character entity.<br /> <br /> 106<br /> <br /> The Most Common Character Entities: Result<br /> <br /> Description<br /> <br /> Entity Name<br /> <br /> Entity Number<br /> <br /> non-breaking space<br /> <br /> &nbsp;<br /> <br /> &#160;<br /> <br /> <<br /> <br /> less than<br /> <br /> &lt;<br /> <br /> &#60;<br /> <br /> ><br /> <br /> greater than<br /> <br /> &gt;<br /> <br /> &#62;<br /> <br /> &<br /> <br /> ampersand<br /> <br /> &amp;<br /> <br /> &#38;<br /> <br /> "<br /> <br /> quotation mark<br /> <br /> &quot;<br /> <br /> &#34;<br /> <br /> '<br /> <br /> apostrophe<br /> <br /> &#39;<br /> <br /> Some Other Commonly Used Character Entities: Result<br /> <br /> Description<br /> <br /> Entity Name<br /> <br /> Entity Number<br /> <br /> ¢<br /> <br /> cent<br /> <br /> &cent;<br /> <br /> &#162;<br /> <br /> £<br /> <br /> pound<br /> <br /> &pound;<br /> <br /> &#163;<br /> <br /> ¥<br /> <br /> yen<br /> <br /> &yen;<br /> <br /> &#165;<br /> <br /> §<br /> <br /> section<br /> <br /> &sect;<br /> <br /> &#167;<br /> <br /> ©<br /> <br /> copyright<br /> <br /> &copy;<br /> <br /> &#169;<br /> <br /> ®<br /> <br /> registered trademark<br /> <br /> &reg;<br /> <br /> &#174;<br /> <br /> ×<br /> <br /> multiplication<br /> <br /> &times;<br /> <br /> &#215;<br /> <br /> ÷<br /> <br /> division<br /> <br /> &divide;<br /> <br /> &#247<br /> <br /> HTML uses a hyperlink to link to another document on the Web. LINKS Examples Create Hyperlinks This example demonstrates how to create links in an HTML document. <html> <body> <p> <a href="lastpage.htm" rel="nofollow"> This text</a> is a link to a page on this Web site. </p><br /> <br /> <p><br /> <br /> 107<br /> <br /> <a href="http://www.microsoft.com/" rel="nofollow"> This text</a> is a link to a page on the World Wide Web. </p> </body> </html> This text is a link to a page on this Web site. This text is a link to a page on the World Wide Web. An Image As A Link This example demonstrates how to use an image as a link. <html> <body> <p> You can also use an image as a link: <a href="lastpage.htm" rel="nofollow"> <img border="0" src="buttonnext.gif" width="65" height="38"> </a> </p> </body> </html><br /> <br /> You can also use an image as a link:<br /> <br /> 108<br /> <br /> The Anchor Tag and the Href Attribute HTML uses the <a> (anchor) tag to create a link to another document. An anchor can point to any resource on the Web: an HTML page, an image, a sound file, a movie, etc. The syntax of creating an anchor:<br /> <br /> <a href="url" rel="nofollow">Text to be displayed</a> The <a> tag is used to create an anchor to link from, the href attribute is used to address the document to link to, and the words between the open and close of the anchor tag will be displayed as a hyperlink. This anchor defines a link to W3Schools:<br /> <br /> <a href="http://www.kapilsingh.com/" rel="nofollow">Visit kapil’s page!</a> The Target Attribute With the target attribute, you can define where the linked document will be opened. The line below will open the document in a new browser window:<br /> <br /> <a href="http://www.kapilsingh.com/" target="_blank" rel="nofollow">Visit kapil’s page!</a> The Anchor Tag and the Name Attribute The name attribute is used to create a named anchor. When using named anchors we can create links that can jump directly into a specific section on a page, instead of letting the user scroll around to find what he/she is looking for. Below is the syntax of a named anchor:<br /> <br /> <a name="label" rel="nofollow">Text to be displayed</a> The name attribute is used to create a named anchor. The name of the anchor can be any text you care to use. The line below defines a named anchor:<br /> <br /> <a name="tips" rel="nofollow">Useful Tips Section</a> You should notice that a named anchor is not displayed in a special way.<br /> <br /> 109<br /> <br /> To link directly to the "tips" section, add a # sign and the name of the anchor to the end of a URL, like this:<br /> <br /> <a href="http://www.w3schools.com/html_links.asp#tips" rel="nofollow"> Jump to the Useful Tips Section</a> A hyperlink to the Useful Tips Section from WITHIN the file "html_links.asp" will look like this:<br /> <br /> <a href="#tips" rel="nofollow">Jump to the Useful Tips Section</a> More Examples Create A Mailto Link This example demonstrates how to link to a mail message (will only work if you have mail installed). <html> <body> <p> This Is A Mail Link <a href="mailto:someone@microsoft.com?subject=Hello%20again" rel="nofollow"> Send Mail</a> </p> <p> <b>Note:</b> Spaces between words should be replaced by %20 to <b>ensure</b> that the browser will display your text properly. </p> </body> </html> This is a mail link: Send Mail Note: Spaces between words should be replaced by %20 to ensure that the browser will display your text properly<br /> <br /> 110<br /> <br /> Link Tags Tag<br /> <br /> Description<br /> <br /> <a><br /> <br /> Defines an anchor<br /> <br /> HTML Frames With frames, you can display more than one Web page in the same browser window. Examples Vertical Frameset This example demonstrates how to make a vertical frameset with three different documents. <html> <frameset cols="25%,50%,25%"> <frame src="tryhtml_frame_a.htm"> <frame src="tryhtml_frame_b.htm"> <frame src="tryhtml_frame_c.htm"> </frameset> </html> Horizontal Frameset This example demonstrates how to make a horizontal frameset with three different documents. <html> <frameset rows="25%,50%,25%"> <frame src="tryhtml_frame_a.htm"> <frame src="tryhtml_frame_b.htm"> <frame src="tryhtml_frame_c.htm"> </frameset><br /> <br /> 111<br /> <br /> </html> How To Use The <Noframes> Tag This example demonstrates how to use the &lt;noframes> tag. <html> <frameset cols="25%,50%,25%"> <frame src="tryhtml_frame_a.htm"> <frame src="tryhtml_frame_b.htm"> <frame src="tryhtml_frame_c.htm"> &lt;noframes> <body>Your browser does not handle frames!</body> </noframes> </frameset> </html> Frames With frames, you can display more than one HTML document in the same browser window. Each HTML document is called a frame, and each frame is independent of the others. The disadvantages of using frames are:<br /> <br /> •<br /> <br /> The web developer must keep track of more HTML documents<br /> <br /> •<br /> <br /> It is difficult to print the entire page<br /> <br /> The Frameset Tag<br /> <br /> •<br /> <br /> The <frameset> tag defines how to divide the window into frames<br /> <br /> •<br /> <br /> Each frameset defines a set of rows or columns<br /> <br /> 112<br /> <br /> •<br /> <br /> The values of the rows/columns indicate the amount of screen area each row/column will occupy<br /> <br /> The Frame Tag<br /> <br /> •<br /> <br /> The <frame> tag defines what HTML document to put into each frame<br /> <br /> In the example below we have a frameset with two columns. The first column is set to 25% of the width of the browser window. The second column is set to 75% of the width of the browser window. The HTML document "frame_a.htm" is put into the first column, and the HTML document "frame_b.htm" is put into the second column:<br /> <br /> <frameset cols="25%,75%"> <frame src="frame_a.htm"> <frame src="frame_b.htm"> </frameset> Basic Notes - Useful Tips If a frame has visible borders, the user can resize it by dragging the border. To prevent a user from doing this, you can add noresize="noresize" to the <frame> tag. Add the &lt;noframes> tag for browsers that do not support frames. Frame Tags Tag<br /> <br /> Description<br /> <br /> <frameset><br /> <br /> Defines a set of frames<br /> <br /> <frame><br /> <br /> Defines a sub window (a frame)<br /> <br /> &lt;noframes><br /> <br /> Defines a noframe section for browsers that do not handle frames<br /> <br /> &lt;iframe><br /> <br /> Defines an inline sub window (frame)<br /> <br /> HTML Tables With HTML you can create tables. Examples Tables This example demonstrates how to create tables in an HTML document. <html> <body> <p><br /> <br /> 113<br /> <br /> Each table starts with a table tag. Each table row starts with a tr tag. Each table data starts with a td tag. </p> <h4>One column:</h4> <table border="1"> <tr> <td>100</td> </tr> </table> <h4>One row and three columns:</h4> <table border="1"> <tr> <td>100</td> <td>200</td> <td>300</td> </tr> </table> <h4>Two rows and three columns:</h4> <table border="1"> <tr> <td>100</td><br /> <br /> 114<br /> <br /> <td>200</td> <td>300</td> </tr> <tr> <td>400</td> <td>500</td> <td>600</td> </tr> </table> </body> </html> Each table starts with a table tag. Each table row starts with a tr tag. Each table data starts with a td tag. One Column 100 One row and three columns: 100 200 300 Two rows and three columns: 100 200 300 400 500 600<br /> <br /> Table Borders This example demonstrates different table borders. <html> <body> <h4>With a normal border:</h4><br /> <br /> 115<br /> <br /> <table border="1"> <tr> <td>First</td> <td>Row</td> </tr> <tr> <td>Second</td> <td>Row</td> </tr> </table> <h4>With a thick border:</h4> <table border="8"> <tr> <td>First</td> <td>Row</td> </tr> <tr> <td>Second</td> <td>Row</td> </tr> </table> <h4>With a very thick border:</h4><br /> <br /> 116<br /> <br /> <table border="15"> <tr> <td>First</td> <td>Row</td> </tr> <tr> <td>Second</td> <td>Row</td> </tr> </table><br /> <br /> </body> </html> With a normal border: First<br /> <br /> Row<br /> <br /> Second Row With a thick border: First<br /> <br /> Row<br /> <br /> Second Row With a very thick border: First<br /> <br /> Row<br /> <br /> Second Row<br /> <br /> (You can find more examples at the bottom of this page)<br /> <br /> 117<br /> <br /> Tables Tables are defined with the <table> tag. A table is divided into rows (with the <tr> tag), and each row is divided into data cells (with the <td> tag). The letters td stands for "table data," which is the content of a data cell. A data cell can contain text, images, lists, paragraphs, forms, horizontal rules, tables, etc.<br /> <br /> <table border="1"> <tr> <td>row 1, cell 1</td> <td>row 1, cell 2</td> </tr> <tr> <td>row 2, cell 1</td> <td>row 2, cell 2</td> </tr> </table> How it looks in a browser:<br /> <br /> row 1, cell 1 row 1, cell 2 row 2, cell 1 row 2, cell 2 Tables and the Border Attribute If you do not specify a border attribute the table will be displayed without any borders. Sometimes this can be useful, but most of the time, you want the borders to show. To display a table with borders, you will have to use the border attribute:<br /> <br /> <table border="1"> <tr> <td>Row 1, cell 1</td> <td>Row 1, cell 2</td> </tr> </table> Headings in a Table Headings in a table are defined with the <th> tag.<br /> <br /> <table border="1"> <tr><br /> <br /> 118<br /> <br /> <th>Heading</th> <th>Another Heading</th> </tr> <tr> <td>row 1, cell 1</td> <td>row 1, cell 2</td> </tr> <tr> <td>row 2, cell 1</td> <td>row 2, cell 2</td> </tr> </table> How it looks in a browser:<br /> <br /> Heading<br /> <br /> Another Heading<br /> <br /> row 1, cell 1 row 1, cell 2 row 2, cell 1 row 2, cell 2<br /> <br /> Empty Cells in a Table Table cells with no content are not displayed very well in most browsers.<br /> <br /> <table border="1"> <tr> <td>row 1, cell 1</td> <td>row 1, cell 2</td> </tr> <tr> <td>row 2, cell 1</td> <td></td> </tr> </table> How it looks in a browser:<br /> <br /> row 1, cell 1 row 1, cell 2 row 2, cell 1 Note that the borders around the empty table cell are missing. To avoid this, add a non-breaking space (&nbsp;) to empty data cells, to make the borders visible:<br /> <br /> 119<br /> <br /> <table border="1"> <tr> <td>row 1, cell 1</td> <td>row 1, cell 2</td> </tr> <tr> <td>row 2, cell 1</td> <td>&nbsp;</td> </tr> </table> How it looks in a browser:<br /> <br /> row 1, cell 1 row 1, cell 2 row 2, cell 1 More Examples Cell Padding This example demonstrates how to use cellpadding to create more white space between the cell content and its borders. <html> <body> <h4>Without cellpadding:</h4> <table border="1"> <tr> <td>First</td> <td>Row</td> </tr> <tr> <td>Second</td> <td>Row</td><br /> <br /> 120<br /> <br /> </tr> </table> <h4>With cellpadding:</h4> <table border="1" cellpadding="10"> <tr> <td>First</td> <td>Row</td> </tr> <tr> <td>Second</td> <td>Row</td> </tr> </table> </body> </html> Without cellpadding: First<br /> <br /> Row<br /> <br /> Second Row With cellpadding: First<br /> <br /> Row<br /> <br /> Second<br /> <br /> Row<br /> <br /> Cell Spacing<br /> <br /> 121<br /> <br /> This example demonstrates how to use cellspacing to increase the distance between the cells. <html> <body> <h4>Without cellspacing:</h4> <table border="1"> <tr> <td>First</td> <td>Row</td> </tr> <tr> <td>Second</td> <td>Row</td> </tr> </table> <h4>With cellspacing:</h4> <table border="1" cellspacing="10"> <tr> <td>First</td> <td>Row</td> </tr> <tr><br /> <br /> 122<br /> <br /> <td>Second</td> <td>Row</td> </tr> </table> </body> </html> Without Cellspacing First<br /> <br /> Row<br /> <br /> Second Row With Cellspacing First<br /> <br /> Row<br /> <br /> Second<br /> <br /> Row<br /> <br /> Add A Background Color Or A Background Image To A Table This example demonstrates how to add a background to a table. <html> <body> <h4>A background color:</h4> <table border="1" bgcolor="red"> <tr> <td>First</td> <td>Row</td><br /> <br /> 123<br /> <br /> </tr> <tr> <td>Second</td> <td>Row</td> </tr> </table> <h4>A background image:</h4> <table border="1" background="/images/bgdesert.jpg"> <tr> <td>First</td> <td>Row</td> </tr> <tr> <td>Second</td> <td>Row</td> </tr> </table> </body> </html> A background Color First<br /> <br /> Row<br /> <br /> Second Row<br /> <br /> 124<br /> <br /> A Background Image First<br /> <br /> Row<br /> <br /> Second Row Table Tags Tag<br /> <br /> Description<br /> <br /> <table><br /> <br /> Defines a table<br /> <br /> <th><br /> <br /> Defines a table header<br /> <br /> <tr><br /> <br /> Defines a table row<br /> <br /> <td><br /> <br /> Defines a table cell<br /> <br /> <caption><br /> <br /> Defines a table caption<br /> <br /> <colgroup><br /> <br /> Defines groups of table columns<br /> <br /> <col><br /> <br /> Defines the attribute values for one or more columns in a table<br /> <br /> <thead><br /> <br /> Defines a table head<br /> <br /> <tbody><br /> <br /> Defines a table body<br /> <br /> <tfoot><br /> <br /> Defines a table footer<br /> <br /> HTML Forms and Input HTML Forms are used to select different kinds of user input. Examples Text Fields This example demonstrates how to create text fields on a HTML page. A user can write text in a text field. <html> <body> <form> First name: <input type="text" name="firstname"> <br> Last name: <input type="text" name="lastname"> </form><br /> <br /> 125<br /> <br /> </body> </html> First<br /> <br /> name:<br /> <br /> Last name: Password Fields This example demonstrates how to create a password field on a HTML page. <html> <body> <form> Username: <input type="text" name="user"> <br> Password: <input type="password" name="password"> </form> <p> Note that when you type characters in a password field, the browser displays asterisks or bullets instead of the characters. </p> </body> </html> Username: Password:<br /> <br /> 126<br /> <br /> Note that when you type characters in a password field, the browser displays asterisks or bullets instead of the characters. Forms A form is an area that can contain form elements. Form elements are elements that allow the user to enter information (like text fields, textarea fields, drop-down menus, radio buttons, checkboxes, etc.) in a form. A form is defined with the <form> tag.<br /> <br /> <form> <input> <input> </form> Input The most used form tag is the <input> tag. The type of input is specified with the type attribute. The most commonly used input types are explained below. Text Fields Text fields are used when you want the user to type letters, numbers, etc. in a form.<br /> <br /> <form> First name: <input type="text" name="firstname"> <br> Last name: <input type="text" name="lastname"> </form> How it looks in a browser: First<br /> <br /> name:<br /> <br /> Last name: Note that the form itself is not visible. Also note that in most browsers, the width of the text field is 20 characters by default. Radio Buttons<br /> <br /> 127<br /> <br /> Radio Buttons are used when you want the user to select one of a limited number of choices.<br /> <br /> <form> <input type="radio" name="sex" value="male"> Male <br> <input type="radio" name="sex" value="female"> Female </form> How it looks in a browser: Male Female Note that only one option can be chosen. Checkboxes Checkboxes are used when you want the user to select one or more options of a limited number of choices.<br /> <br /> <form> <input type="checkbox" name="bike"> I have a bike <br> <input type="checkbox" name="car"> I have a car </form> How it looks in a browser: I<br /> <br /> have<br /> <br /> a<br /> <br /> bike<br /> <br /> I have a car The Form's Action Attribute and the Submit Button When the user clicks on the "Submit" button, the content of the form is sent to another file. The form's action attribute defines the name of the file to send the content to. The file defined in the action attribute usually does something with the received input.<br /> <br /> <form name="input" action="html_form_action.asp" method="get"> Username: <input type="text" name="user"> <input type="submit" value="Submit"><br /> <br /> 128<br /> <br /> </form> How it looks in a browser: Username: If you type some characters in the text field above, and click the "Submit" button, you will send your input to a page called "html_form_action.asp". That page will show you the received input. Form Examples Form With Input Fields And A Submit Button This example demonstrates how to add a form to a page. The form contains two input fields and a submit button. <html> <body> <form name="input" action="html_form_action.asp" method="get"> Enter your first name: <input type="text" name="FirstName" value="Mickey"> <br>Enter your last name: <input type="text" name="LastName" value="Mouse"> <br> <input type="submit" value="Submit"> </form> <p> If you click the "Submit" button, you will send your input to a new page called html_form_action.asp. </p> </body> </html><br /> <br /> 129<br /> <br /> Enter<br /> <br /> your<br /> <br /> first<br /> <br /> name:<br /> <br /> Enter<br /> <br /> your<br /> <br /> last<br /> <br /> name:<br /> <br /> If you click the "Submit" button, you will send your input to a new page called html_form_action.asp. Send E-Mail From A Form This example demonstrates how to send e-mail from a form. <html> <body> <form action="MAILTO:someone@w3schools.com" method="post" enctype="text/plain"> <h3>This form sends an e-mail to W3Schools.</h3> Name:<br> <input type="text" name="name" value="yourname" size="20"> <br> Mail:<br> <input type="text" name="mail" value="yourmail" size="20"> <br> Comment:<br> <input type="text" name="comment" value="yourcomment" size="40"> <br><br> <input type="submit" value="Send"><br /> <br /> 130<br /> <br /> <input type="reset" value="Reset"> </form> </body> </html><br /> <br /> This form sends an e-mail to W3Schools. Name: Mail: Comment:<br /> <br /> Form Tags Tag<br /> <br /> Description<br /> <br /> <form><br /> <br /> Defines a form for user input<br /> <br /> <input><br /> <br /> Defines an input field<br /> <br /> <textarea><br /> <br /> Defines a text-area (a multi-line text input control)<br /> <br /> <label><br /> <br /> Defines a label to a control<br /> <br /> <fieldset><br /> <br /> Defines a fieldset<br /> <br /> <legend><br /> <br /> Defines a caption for a fieldset<br /> <br /> &lt;select><br /> <br /> Defines a selectable list (a drop-down box)<br /> <br /> <optgroup><br /> <br /> Defines an option group<br /> <br /> <option><br /> <br /> Defines an option in the drop-down box<br /> <br /> <button><br /> <br /> Defines a push button<br /> <br /> <isindex><br /> <br /> Deprecated. Use <input> instead<br /> <br /> HTML Images With HTML you can display images in a document. Examples Insert Images This example demonstrates how to display images in your Web page.<br /> <br /> 131<br /> <br /> <html> <body> <p> An image: <img src="constr4.gif" width="144" height="50"> </p> <p> A moving image: <img src="hackanm.gif" width="48" height="48"> </p> <p> Note that the syntax of inserting a moving image is no different from that of a non-moving image. </p> </body> </html><br /> <br /> Image<br /> <br /> A moving image: Note that the syntax of inserting a moving image is no different from that of a non-moving image.<br /> <br /> 132<br /> <br /> The Image Tag and the Src Attribute In HTML, images are defined with the <img> tag. The <img> tag is empty, which means that it contains attributes only and it has no closing tag. To display an image on a page, you need to use the src attribute. Src stands for "source". The value of the src attribute is the URL of the image you want to display on your page. The syntax of defining an image:<br /> <br /> <img src="url"> The URL points to the location where the image is stored. An image named "boat.gif" located in the directory "images" on "www.kapilsingh.com" has the URL: http://www.kapilsingh.com/images/boat.gif. The browser puts the image where the image tag occurs in the document. If you put an image tag between two paragraphs, the browser shows the first paragraph, then the image, and then the second paragraph. The Alt Attribute The alt attribute is used to define an "alternate text" for an image. The value of the alt attribute is an author-defined text:<br /> <br /> <img src="boat.gif" alt="Big Boat"> The "alt" attribute tells the reader what he or she is missing on a page if the browser can't load images. The browser will then display the alternate text instead of the image. It is a good practice to include the "alt" attribute for each image on a page, to improve the display and usefulness of your document for people who have text-only browsers. More Examples Display An Alternate Text For An Image This example demonstrates how to display an alternate text for an image. The "alt" attribute tells the reader what he or she is missing on a page if the browser can't load images. It is a good practice to include the "alt" attribute for each image on a page. <html> <body> <img src="/images/goleft.gif" alt="Go Left" width="32" height="32"><br /> <br /> 133<br /> <br /> <p> Text-only browsers will only display the text in the "alt" attribute, which is "Go Left". Note that if you hold the mouse pointer over the image it will display the text. </p> </body> </html><br /> <br /> Text-only browsers will only display the text in the "alt" attribute, which is "Go Left". Note that if you hold the mouse pointer over the image it will display the text. Image Tags Tag<br /> <br /> Description<br /> <br /> <img><br /> <br /> Defines an image<br /> <br /> &lt;map><br /> <br /> Defines an image map<br /> <br /> &lt;area><br /> <br /> Defines an area inside an image map<br /> <br /> HTML Backgrounds A good background can make a Web site look really great. The <body> tag has two attributes where you can specify backgrounds. The background can be a color or an image. Bgcolor The bgcolor attribute sets the background to a color. The value of this attribute can be a hexadecimal number, an RGB value, or a color name.<br /> <br /> <body bgcolor="#000000"> <body bgcolor="rgb(0,0,0)"> <body bgcolor="black"> The lines above all set the background color to black.<br /> <br /> Background<br /> <br /> 134<br /> <br /> The background attribute sets the background to an image. The value of this attribute is the URL of the image you want to use. If the image is smaller than the browser window, the image will repeat itself until it fills the entire browser window.<br /> <br /> <body background="clouds.gif"> <body background="http://www.kapilsingh.com/clouds.gif"> The URL can be relative (as in the first line above) or absolute (as in the second line above). Note: If you want to use a background image, you should keep in mind:<br /> <br /> •<br /> <br /> Will the background image increase the loading time too much? Tip: Image files should be maximum 10k<br /> <br /> •<br /> <br /> Will the background image look good with other images on the page?<br /> <br /> •<br /> <br /> Will the background image look good with the text colors on the page?<br /> <br /> •<br /> <br /> Will the background image look good when it is repeated on the page?<br /> <br /> •<br /> <br /> Will the background image take away the focus from the text?<br /> <br /> Basic Notes - Useful Tips The bgcolor, background, and the text attributes in the <body> tag are deprecated in the latest versions of HTML (HTML 4 and XHTML). The World Wide Web Consortium (W3C) has removed these attributes from its recommendations. In future versions of HTML, style sheets (CSS) will be used to define the layout and display properties of HTML elements. Few of the most visited web sites use background images. The most used background colors are: white, black and gray. More Examples Good Background Image A<html> <body background="background.jpg"> <h3>Image Background</h3> <p>Both gif and jpg files can be used as HTML backgrounds.</p> <p>If the image is smaller than the page, the image will repeat itself.</p><br /> <br /> 135<br /> <br /> </body> </html> In example of a background image and a text color that makes the text on the page easy to read. HTML Styles With HTML 4.0 all formatting can be moved out of the HTML document and into a separate style sheet. Examples Styles In HTML This example demonstrates how to format an HTML document with style information added to the <head> section. <html> <head> &lt;style> h1 {color: red} h3 {color: blue} </style> </head> <body> <h1>This is header 1</h1> <h3>This is header 3</h3> </body> </html> This is header 1 This is header 3<br /> <br /> 136<br /> <br /> How to Use Styles When a browser reads a style sheet, it will format the document according to it. There are three ways of inserting a style sheet: External Style Sheet An external style sheet is ideal when the style is applied to many pages. With an external style sheet, you can change the look of an entire Web site by changing one file. Each page must link to the style sheet using the <link> tag. The <link> tag goes inside the head section.<br /> <br /> <head> <link rel="stylesheet" type="text/css" href="mystyle.css"> </head> Internal Style Sheet An internal style sheet should be used when a single document has a unique style. You define internal styles in the head section with the &lt;style> tag.<br /> <br /> <head> &lt;style type="text/css"> body {background-color: red} p {margin-left: 20px} </style> </head><br /> <br /> Inline Styles An inline style should be used when a unique style is to be applied to a single occurrence of an element. To use inline styles you use the style attribute in the relevant tag. The style attribute can contain any CSS property. The example shows how to change the color and the left margin of a paragraph:<br /> <br /> <p style="color: red; margin-left: 20px"> This is a paragraph </p> Style Tags Tag<br /> <br /> Description<br /> <br /> &lt;style><br /> <br /> Defines a style definition<br /> <br /> 137<br /> <br /> <link><br /> <br /> Defines a resource reference<br /> <br /> <div><br /> <br /> Defines a section in a document<br /> <br /> &lt;span><br /> <br /> Defines a section in a document<br /> <br /> <font><br /> <br /> Deprecated. Use styles instead<br /> <br /> <basefont><br /> <br /> Deprecated. Use styles instead<br /> <br /> <center><br /> <br /> Deprecated. Use styles instead<br /> <br /> Office automation system (OAS) OAS provides individuals effective ways to process personal and organisational data, perform calculations, and create documents. e.g.<br /> <br /> word<br /> <br /> processing,<br /> <br /> spreadsheets,<br /> <br /> file<br /> <br /> managers,<br /> <br /> personal<br /> <br /> calendars,<br /> <br /> presentation<br /> <br /> packages<br /> <br /> For are used for increasing personal productivity. They reduce "paper warfare". OAS software tools are often integrated (e.g. Word processor can import a graph from a spreadsheet) and designed for easy operation. OAS Subspecies Communication systems: helps people work together by sharing information in many different forms Teleconferencing (including audio conferencing, computer conferencing, videoconferencing), electronic mail, voice mail, fax Groupware system: helps teams work together by providing access to team data, structuring communication, and making it easier to schedule meetings. For sharing information, controlling work flows, communication/integration of work Extranet Nowadays, we hear many terms that have similar meanings. For example, Internet, intranet and extranet. These are all networks, which provide services that are slightly different from each other. Each network may also have different standards that are constantly changing, as the IT field continuously progresses. The Internet came first and linked users around the globe via phone lines, dedicated lines or through other networks. Intranets, which links users in one organization, followed. Firewalls separate intranets from the Internet and prevent outside users from accessing the internal networks unless they are authorized. Then came extranets, as a means to link intranets of various companies with their business partners. Such companies are in the fields of education, trade and marketing. What is an extranet? An extranet is a network that links intranets together via the Internet. It can link intranets of business partners, suppliers and researchers, or different intranets belonging to a central management. It enables users to share information and gives permission to access some files and services, whilst preserving the privacy of each intranet site.<br /> <br /> 138<br /> <br /> An extranet can be used for the following applications:<br /> <br /> •<br /> <br /> Client training.<br /> <br /> •<br /> <br /> Sharing of databases between universities and research centers belonging to one company or organization.<br /> <br /> •<br /> <br /> Networking systems of financial institutions.<br /> <br /> •<br /> <br /> Personnel and resource management in multinational companies.<br /> <br /> Types of Extranet Extranets were developed as a response to the needs of partnerships in the business sector. Such relationships between business partners are called B2B( Business to Business). They need a network, which will enable them to exchange sensitive information via setting levels of network accessibility.<br /> <br /> There are different types of extranet. Based on the business sector, extranets are classified as: Supplier<br /> <br /> Extranets<br /> <br /> A supplier extranet links store branches to their central store, in order to facilitate workflow and maintain the required level of stocks in the inventory. It reduces the possibility of rejecting orders due to shortage of stocks, in addition to providing many services related to inventory control.<br /> <br /> 139<br /> <br /> Distributor Extranet A distributor extranet gives different levels of authorization to various individuals, depending on the size of the dealings. It also provides services such as electronic order and automated settlements, as well as lists of new products and specifications. The diagram below illustrates the difference between a supplier and distributor extranet.<br /> <br /> Peer Extranet A peer extranet promotes equal competition between the different companies in the business sector, as it links small and large companies and enables them to share product prices and specifications. This helps to improve the product and services of a company, and in curbing monopoly Extranets connect the Internetworked enterprise to consumers, business customers, suppliers, and other business partners.<br /> <br /> Partners, Consultants, Contractors • Joint Design • Outsourcing<br /> <br /> Suppliers & Distributors • Distributor Management • Supply Chain Management • Procurement<br /> <br /> The Internetworked Enterprise<br /> <br /> 140<br /> <br /> Business Customers<br /> <br /> Consumer • Customer Self-Service • Sales Force Automation • Built to Order Products • Just in Time Ordering<br /> <br /> Advantages of an Extranet Many companies have gained numerous benefits from extranets. Gelco Information Network Inc. achieved success by using an extranet to help their clients check the cost of voyages and trips they offer. Implementing an extranet proved to be very effective. The company achieved high returns, which would have been impossible using typical methods of communications. The following are some of the different approaches in which an extranet can improve the productivity of a company and help it move towards the digital world. Facilitating Purchases For example, a company in the Middle East can order from a Japanese company without the need to use typical means of communication. Tracking Invoices An extranet can facilitate signing any electronic document that needs more than one digital signature. For example, it allows different branch managers to collect and sign an invoice indicating the different processing steps. Employment Services Extranets are used to link the students of universities, institutions and training centers to the labor market. Both sides benefit from this service. Through an extranet, the students will be able to find the right job opportunity and the labor market can meet its needs. Linking Distribution Networks It is possible to build extranets that link distributors with main suppliers. This accelerates operations in the processing and shipping of orders. It is also possible to develop an application based on the concept of request point, to automate<br /> <br /> 141<br /> <br /> distribution and payments. In this case, when the distributor’s stocks of a certain product fall below a preset quantity (called request point) a message will be sent to the supplier to request more of that product. Future Of Extranets Extranets are now one of the most popular technologies in the information age. Analysts and researchers expect extranets to replace special purpose networks that are currently used in the fields of e-businesses and e-commerce, as extranets are cheaper to build than special purpose networks, in addition to their capability in facilitating management operations and improving communications with the clients. Among the actual applications of extranet are the following:Remote access<br /> <br /> •<br /> <br /> Branch office connectivity<br /> <br /> •<br /> <br /> Mainframe access<br /> <br /> •<br /> <br /> Web browsing interface<br /> <br /> •<br /> <br /> EDI (Electronic Data Interchange)<br /> <br /> Recently, extranet applications were made available on the web. You can now access your files through a web site, using a previously agreed upon ID and password. There are also e-catalogs, which allows clients to check offers, prices, delivery schedules and other information. Accessing regular web sites and services requires an account on the server. However, a password is needed to access specific services and information. There are already many companies shifting to extranets in order to better serve the interests of themselves and their clients, and gain competitiveness within a very short period of time.<br /> <br /> REVIEW EXERCISES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.<br /> <br /> Differentiate between intranet and internet. Discuss the benefits of Intranet. How will you establish an intranet. Why is intranet getting popularity these days.Explain. Explain various applications of Intranets. What are the tips to implement an intranet How is video-conferencing useful. Differentiate between internet,intranet and extranet. Explain the business use of intranets. What is an office automation system.how is it useful. What are the behavioral factors essential for constructing and implementing an Intranet. Explain the usage of Extranets.<br /> <br /> 142<br /> <br /> UNIT III Microsoft BackOffice products are a suite of applications which are optimized for Windows NT/2000 and which help businesses perform critical computing functions such as e-mail, inventory management, database management, and more. ELECTRONIC MAIL At the beginning of the internet era, the message sent by electronic mail were short and consisted of text only. Today, electronic mail is much more complex. It allows a message to include text, audio, and video. I also allow one message to be sent to one or more recipients. First Scenario The sender and the receiver of the e-mail are users on the same system; they are directly connected to a shared system. The administrator has created one mailbox for each user where the received messages are stored. A mailbox is part of a local hard drive, a special file with permission restrictions. Only the owner of the mailbox has access to it. When Alice, a user, need to send a message to Bob, another user, Alice runs a user agent (UA) program to prepare the message and `<br /> <br /> UA: user agent<br /> <br /> 143<br /> <br /> UA<br /> <br /> UA Alice<br /> <br /> Bob<br /> <br /> System When the sender and the receiver of an e-mail are on the same system, We need only two user agents. Second Scenario In the second scenario, the sender and receiver of the e-mail are users on two different systems. The message needs to be sent over the Internet. User agents (UAs) and message transfer agents (MTAs), Figure – Second scenario in electronic mail UA: user agent MTA: message transfer agent UA<br /> <br /> UA Alice<br /> <br /> Bob MTA client<br /> <br /> MTA Server<br /> <br /> Internet System<br /> <br /> System<br /> <br /> (Mail server)<br /> <br /> (Mail server)<br /> <br /> Alice needs to use a user agent program to send her message to the system at her own site. The system at her site uses a queue to store message waiting to be sent. Bob also needs a user agent program to retrieve message stored in the mailbox of the system at his site. The message, however, needs to be sent through the Internet from Alice’s site to Bob’s site. Here two message transfer agents are needed: one client and one server. Link most client/server programs on the Internet, the server needs to run all the time because it does not known when a client will ask for a connection. The client, on the other hand, can be alerted by the system when there is a message in the queue to be sent. When the sender and the receiver of an e-mail are on different systems, We need two UAs and a pair of MTAs (client and server). Third Scenario Bob is also connected to his mail server by a WAN or a LAN. After the message has arrived at Bob’s mail server, Bob needs to retrieve it. Here, we need another set of client/server agent, which we call message access agents (MAAs). Bob uses an MAA client to retriever his messages. The client sends a request to the MAA server, which is running all the time, and requests the transfer of the messages. Figure Third scenario in electronic mail<br /> <br /> 144<br /> <br /> UA<br /> <br /> MT<br /> <br /> MAA<br /> <br /> client<br /> <br /> client<br /> <br /> UA<br /> <br /> Alice<br /> <br /> Bob<br /> <br /> LAN or WAN<br /> <br /> LAN or WAN<br /> <br /> MAA Server<br /> <br /> MTA Server<br /> <br /> MTA Client<br /> <br /> MTA Serve r<br /> <br /> Internet System<br /> <br /> System<br /> <br /> Figure Push versus pull electronic email MTA<br /> <br /> MTA<br /> <br /> client<br /> <br /> server Client pushes messages<br /> <br /> Client pulls message<br /> <br /> When both sender and receiver are connected to the mail server via a LAN or a WAN, We need two UAs, two pairs of MTAs (client and server), and a pair of MAAs (client and server). This is the most common situation today.<br /> <br /> 145<br /> <br /> 1. User Agent The first component of an electronic mail system is the user agent (UA). It provides service to the user to make the process of sending and receiving a message easier. Figure- Services of user agent User Agent<br /> <br /> Composing Messages<br /> <br /> Reading message<br /> <br /> Replying to message<br /> <br /> Forwarding message<br /> <br /> Handling<br /> <br /> message<br /> <br /> MIME Electronic mail has a simple structure. It can send message only in 7-bit ASCII format. It cannot be used for languages that are not supported by 7bit ASCII characters (such as French, German, Hebrew, Russian, Chinese, and Japanese). Also, it cannot be used to send binary files or video or audio data. Multipurpose Internet Mail Extensions (MIME) is a supplementary protocol that allows non-ASCII data to be sent through e-mail. MIME transforms non-ASCII data at the sender site to7bit ASCII data and delivers them to the client MTA to be sent through the internet. The message at the receiving side is transformed back to the original data. MIME is a set of software functions that transforms non-ASCII data (stream of bits) to ASCII data and vice versa.<br /> <br /> Figure- MIME UA<br /> <br /> UA Non-ASCII code<br /> <br /> Non-ASCII code<br /> <br /> MIME<br /> <br /> MIME 7-bit ASCII<br /> <br /> MTA<br /> <br /> 7-bit ASCII<br /> <br /> 7-bit ASCII<br /> <br /> MTA<br /> <br /> MIME defines five headers that can be added to the original e-mail header section to define the transformation parameters: 1.<br /> <br /> MIME- version<br /> <br /> 146<br /> <br /> 2.<br /> <br /> Content-type<br /> <br /> 3.<br /> <br /> Content-Transfer-Encoding<br /> <br /> 4.<br /> <br /> Content-Id<br /> <br /> 5.<br /> <br /> Content-Description<br /> <br /> MIME-Version This header defines the version of MIME used. Content-type This header defines the type of data used in the body of the message. MIME allow seven different types of data Table - Data types and subtypes in MIME Type Text Multipart Message<br /> <br /> Some subtypes<br /> <br /> Image<br /> <br /> are Image- JPEG GIF,<br /> <br /> Video<br /> <br /> Text- Plain, HTML<br /> <br /> Audio Application Content-Transfer-Encoding This header defines the method used to encode the message into 0s and1s for transport. Content-Id This header uniquely identifies the whole message in a multiple-message environment. Content-Description This header defines whether the body is image, audio, or video. 2. Message Transfer Agent: SMTP The actual mail transfer is done through message transfer agents. To send mail, a system must have the client MTA, and to receive mail, a system must have a server MTA. The formal protocol that defines the MTA client and server in the Internet is called the Simple Mail Transfer Protocol (SMTP). Figure<br /> <br /> SMTP SMTP<br /> <br /> Sender<br /> <br /> Receiver<br /> <br /> LAN or<br /> <br /> LAN or Wan<br /> <br /> Wan Mail server<br /> <br /> Internet<br /> <br /> Mail server<br /> <br /> 147<br /> <br /> SMTP is used two times, between the sender and the sender’s mail server and between two mail servers. SMTP simply defines how commands and responses must be sent back and forth. Figure – Commands and responses Commands MTA<br /> <br /> MTA Client<br /> <br /> Responses<br /> <br /> Mail Transfer Phases The process of transferring a mail message occurs in three phases: connection establishment, mail transfer, and connection termination. Message Access Agent: POP and IMAP The first and the second stages of mail delivery use SMTP. However, SMTP is not involved in the third stage because SMTP is a push protocol; it pushed the message from the client to the server. In other worlds, the direction of the bulk data (message) is from the client to the server. On the other hand, the third stage needs a pull protocol; the client must pull message from the server. The direction of the bulk data is from the server to the client. The third stage uses a message access agent. Currently two message access protocols are available: Post Office Protocol, version 3(POP3) and Internet Mail Access Protocol, version 4(IMAP4) POP3 Post office Protocol, version 4(IMAP4) is simple and limited in functionality. The client POP3 software is installed on the recipient computer, the server POP3 software is installed on the mail server. Mail access start with the client when the user needs to download e-mail from the mailbox on the mail server. POP3 has two modes; the delete mode and the keep mode. In the delete mode, the mail is deleted from the mailbox after each retrieval in the keep mode, the mail remains in the mailbox after retrieval. IMAP4 Internet Mail Protocol, version 4(IMAP4). Is similar to POP3, but it has more features; is more powerful and more complex. Figure The exchange of commands and responses in POP POP 3<br /> <br /> POP 3 Server<br /> <br /> client User-name OK Password OK List e-mail number and their sizes Retriever 1<br /> <br /> 148<br /> <br /> e-mail 1 Retrieve N e-mail Electronic Communication Tools Electronic communication tools help you to communicate and collaborate with others by electronically sending messages, documents, and files in data, text, voice, or multimedia over the Internet, intranets, extranets, and other computer networks.<br /> <br /> •<br /> <br /> Electronic Mail. Widely used to send and receive text messages between networked PCs over telecommunications networks. E-mail can also include data files, software, and multimedia messages and documents as attachments.<br /> <br /> •<br /> <br /> Voice Mail. Unanswered telephone messages are digitized, stored, and played back to you by a voice messaging computer.<br /> <br /> •<br /> <br /> Faxing. Transmitting and receiving images of documents over telephone or computer networks using PCs or fax machines.<br /> <br /> •<br /> <br /> Web Publishing. Creating, converting and storing hyperlinked documents and other material on Internet or intranet Web servers so they can easily be shared via Web browsers or netcasting with teams, workgroup , or the enterprise.<br /> <br /> ***** Requirements Backoffice server 4.5 with 1 server license and 5 clients access licenses (CAL) marketed for $675US. It required 2 Gigabytes minimum hard drive space, a minimum processor type of Pentium Pro 200 MHz, and a minimum RAM size of 128 megabytes.<br /> <br /> FIGURE Functions of the current BackOffice family. Here is a list of key functions of the BackOffice family (see Figure 1.2):<br /> <br /> 149<br /> <br /> •<br /> <br /> A server operating system that provides the basic file storage, peripheral handling, and network transmission capabilities for the product suite.<br /> <br /> •<br /> <br /> An intranet/Internet server suite to provide the basic functions of a World Wide Web server and a File Transfer Protocol server. There is also a Gopher server to facilitate looking for information that is not available through standard Web services.<br /> <br /> •<br /> <br /> A relational database management system that can handle the storage and retrieval of organized collections of data common to most business environments.<br /> <br /> •<br /> <br /> An electronic mail system to handle basic messaging functions facilitating communication between users and between applications. This package can be extended to serve as groupware (software designed to facilitate collaboration by exchanging messages in more of a dialog format and also supporting forms for data collection and display).<br /> <br /> •<br /> <br /> A connectivity solution for legacy mainframe environments. This package acknowledges that there is a lot of data on IBM mainframes and AS/400 computers that run in their own network environments. This package provides the bridge into those environments.<br /> <br /> •<br /> <br /> A management solution for computers on the network. This product enables you to control inventory, update software, and provide better help desk support.<br /> <br /> Microsoft is already working to extend the functions of this product family. Key components of this expansion include the following:<br /> <br /> •<br /> <br /> An Internet proxy server that provides controlled access to the Internet<br /> <br /> •<br /> <br /> An Internet merchant server to provide support for retail operations over the Internet and intranets<br /> <br /> •<br /> <br /> A media server that enables you to have real-time access to audio and video information stored electronically on a server<br /> <br /> •<br /> <br /> A catalog server that provides access services for large published information collections<br /> <br /> Microsoft BackOffice Server was a computer software package featuring Windows NT Server and other Microsoft server products that ran on NT server. It was marketed during the 1990s and early 2000s for use in branch operations and for small businesses to run their Back office operations. The small business edition of BackOffice Server was spun off by its third release, becoming a variant of Windows Server branded as Windows Small Business Server and available in a standard and a premium edition. BackOffice Server itself was discontinued on October 1, 2001. Besides Windows NT Server, versions of BackOffice Server suite also included Microsoft SQL Server, Microsoft SNA Server, Microsoft Systems Management Server (SMS), Microsoft Mail Server or Microsoft Exchange Server, Microsoft Proxy Server or Microsoft Internet Security and Acceleration (ISA) Server, and Internet Information Services (IIS). Versions<br /> <br /> •<br /> <br /> late 1994 — BackOffice 1.0<br /> <br /> includes Windows NT Server 3.5, SQL Server 4.21a, SNA Server 2.1, SMS 1.0, and Mail Server 3.2.<br /> <br /> •<br /> <br /> late 1995 — BackOffice 1.5<br /> <br /> 150<br /> <br /> includes Windows NT Server 3.51, SQL Server 6.0, SNA Server 2.11, SMS 1.1, and Mail Server 3.5.<br /> <br /> •<br /> <br /> April 25, 1996 — BackOffice 2.0<br /> <br /> includes Windows NT Server 3.51, SQL Server 6.0 or 6.5, SNA Server 2.11, SMS 1.1, IIS 1.0, and Exchange Server 4.0.<br /> <br /> •<br /> <br /> December 1996 — BackOffice 2.5<br /> <br /> includes Windows NT Server 4.0, SQL Server 6.5, SNA Server 3.0, SMS 1.2, IIS 2.0, Exchange Server 4.0, Proxy Server 1.0, Index Server 1.1, Internet Explorer 3.01, and FrontPage 1.1<br /> <br /> •<br /> <br /> December 9, 1997 — BackOffice Server 4.0<br /> <br /> includes Windows NT Server 4.0, SQL Server 6.5, SNA Server 4.0, SMS 1.2, IIS 4.0, Exchange Server 5.5, Proxy Server 2.0, Index Server 2.0, Transaction Server 2.0, FrontPage 98, and Visual InterDev 1.0.<br /> <br /> •<br /> <br /> January 12, 1999 — BackOffice Server 4.5<br /> <br /> includes Windows NT Server 4.0 SP4, SQL Server 7.0, SNA Server 4.0, SMS 2.0, IIS 4.0, Exchange Server 5.5, Proxy Server 2.0, Index Server 2.0, Transaction Server 2.0, Internet Explorer 5.0, FrontPage 2000, and Visual InterDev 6.0.<br /> <br /> •<br /> <br /> February 28, 2001 — BackOffice Server 2000<br /> <br /> includes Windows 2000 Server, SQL Server 2000, SMS 2.0, Exchange Server 2000, ISA Server 2000, and Host Integration Server 2000. Requirements Backoffice server 4.5 with 1 server license and 5 clients access licenses (CAL) marketed for $675US. It required 2 Gigabytes minimum hard drive space, a minimum processor type of Pentium Pro 200 MHz, and a minimum RAM size of 128 megabytes.<br /> <br /> FIGURE Functions of the current BackOffice family. Here is a list of key functions of the BackOffice family (see Figure 1.2):<br /> <br /> •<br /> <br /> A server operating system that provides the basic file storage, peripheral handling, and network transmission capabilities for the product suite.<br /> <br /> •<br /> <br /> An intranet/Internet server suite to provide the basic functions of a World Wide Web server and a File Transfer Protocol server. There is also a Gopher server to facilitate looking for information that is not available through standard Web services.<br /> <br /> •<br /> <br /> A relational database management system that can handle the storage and retrieval of organized collections of data common to most business environments.<br /> <br /> 151<br /> <br /> •<br /> <br /> An electronic mail system to handle basic messaging functions facilitating communication between users and between applications. This package can be extended to serve as groupware (software designed to facilitate collaboration by exchanging messages in more of a dialog format and also supporting forms for data collection and display).<br /> <br /> •<br /> <br /> A connectivity solution for legacy mainframe environments. This package acknowledges that there is a lot of data on IBM mainframes and AS/400 computers that run in their own network environments. This package provides the bridge into those environments.<br /> <br /> •<br /> <br /> A management solution for computers on the network. This product enables you to control inventory, update software, and provide better help desk support.<br /> <br /> Microsoft is already working to extend the functions of this product family. Key components of this expansion include the following:<br /> <br /> •<br /> <br /> An Internet proxy server that provides controlled access to the Internet<br /> <br /> •<br /> <br /> An Internet merchant server to provide support for retail operations over the Internet and intranets<br /> <br /> •<br /> <br /> A media server that enables you to have real-time access to audio and video information stored electronically on a server<br /> <br /> •<br /> <br /> A catalog server that provides access services for large published information collections<br /> <br /> Teleconference Teleconference is the live exchange and mass articulation of information among persons and machines remote from one another but linked by a telecommunications system, usually over the phone line. It differs from videophone in intending to serve groups rather than individuals. The telecommunications system may support the teleconference by providing one or more of the following audio, video, and/or data services by one or more means, such as telephone, telegraph, teletype, radio, and television. Teleconferences are also referred to as teleseminars. Alternative terms for teleconferencing include audio conferencing, telephone conferencing and phone conferencing. Internet Tele-conference Internet telephony involves conducting a teleconference over the Internet or a Wide Area Network. One key technology in this area is Voice over Internet Protocol (VOIP). Popular software for personal use includes Skype, Google Talk, Windows Live Messenger and Yahoo Messenger. A List of commercial voice over IP network providers is available. Videoconference A videoconference (also known as a videoteleconference) is a set of interactive telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously. It has also been called visual collaboration and is a type of groupware. It differs from videophone in that it is designed to serve a conference rather than individuals. Videoconferencing uses telecommunications of audio and video to bring people at different sites together for a meeting. This can be as simple as a conversation between two people in private offices (point-to-point) or involve several sites (multi-point) with more than one person in large rooms at different sites. Besides the audio and visual transmission of meeting activities, videoconferencing can be used to share documents, computer-displayed information, and whiteboards. Simple analog videoconferences could be established as early as the invention of the television. Such videoconferencing systems consisted of two closed-circuit television systems connected via cable. During the first<br /> <br /> 152<br /> <br /> manned space flights, NASA used two radiofrequency (UHF or VHF) links, one in each direction. TV channels routinely use this kind of videoconferencing when reporting from distant locations, for instance. Then mobile links to satellites using specially equipped trucks became rather common The core technology used in a videoteleconference (VTC) system is digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1s and 0s is subdivided into labelled packets, which are then transmitted through a digital network of some kind (usually ISDN or IP). The use of audio modems in the transmission line allow for the use of POTS, or the Plain Old Telephone System, in some low-speed applications, such as videotelephony, because they convert the digital pulses to/from analog waves in the audio spectrum range. The other components required for a VTC system include:<br /> <br /> •<br /> <br /> Video input : video camera or webcam<br /> <br /> •<br /> <br /> Video output: computer monitor , television or projector<br /> <br /> •<br /> <br /> Audio input: microphones<br /> <br /> •<br /> <br /> Audio output: usually loudspeakers associated with the display device or telephone<br /> <br /> •<br /> <br /> Data transfer: analog or digital telephone network, LAN or Internet<br /> <br /> There are basically two kinds of VTC systems:<br /> <br /> 1.<br /> <br /> Dedicated systems (manufactured by companies such as Polycom, Sony, Tandberg, Radvision Ltd., and LifeSize) have all required components packaged into a single piece of equipment, usually a console with a high quality remote controlled video camera. These cameras can be controlled at a distance to pan left and right, tilt up and down, and zoom. They became known as PTZ cameras. The console contains all electrical interfaces, the control computer, and the software or hardware-based codec. Omnidirectional microphones are connected to the console, as well as a TV monitor with loudspeakers and/or a video projector. There are several types of dedicated VTC devices:<br /> <br /> 1.<br /> <br /> Large group VTC are non-portable, large, more expensive devices used for large rooms and auditoriums.<br /> <br /> 2.<br /> <br /> Small group VTC are non-portable or portable, smaller, less expensive devices used for small meeting rooms.<br /> <br /> 3.<br /> <br /> Individual VTC are usually portable devices, meant for single users, have fixed cameras, microphones and loudspeakers integrated into the console.<br /> <br /> 2.<br /> <br /> Desktop systems are add-ons (hardware boards, usually) to normal PCs, transforming them into VTC devices. A range of different cameras and microphones can be used with the board, which contains the necessary codec and transmission interfaces. Most of the desktops systems work with the H.323 standard. Videoconferences carried out via dispersed PCs are also known as e-meetings.<br /> <br /> Issues Some observers argue that two outstanding issues are preventing videoconferencing from becoming a standard form of communication, despite the ubiquity of videoconferencing-capable systems. These issues are:<br /> <br /> 1.<br /> <br /> Eye Contact: It is known that eye contact plays a large role in conversational turn-taking, perceived attention and intent, and other aspects of group communication. [3] While traditional telephone conversations give no eye contact cues, videoconferencing systems are arguably worse in that they provide an incorrect impression that the remote interlocutor is avoiding eye contact. Telepresence systems such as the Polycom RPX have cameras located in the screens that reduce the amount of parallax observed by the users. This issue is also being addressed through research that generates a synthetic image with eye contact using stereo reconstruction.[4]<br /> <br /> 153<br /> <br /> 2.<br /> <br /> Appearance Consciousness: A second problem with videoconferencing is that one is on camera, with the video stream possibly even being recorded. The burden of presenting an acceptable on-screen appearance is not present in audio-only communication. Early studies by Alphonse Chapanis found that the addition of video actually impaired communication, possibly because of the consciousness of being on camera.<br /> <br /> The issue of eye-contact may be solved with advancing technology, and presumably the issue of appearance consciousness will fade as people become accustomed to videoconferencing. Impact on the general public High speed Internet connectivity has become more widely available at a reasonable cost and the cost of video capture and display technology has decreased. Consequently personal video teleconference systems based on a webcam, personal computer system, software compression and broadband Internet connectivity have become affordable for the general public. Also, the hardware used for this technology has continued to improve in quality, and prices have dropped dramatically. The availability of freeware (often as part of chat programs) has made software based videoconferencing accessible to many. For many years, futurists have envisioned a future where telephone conversations will take place as actual face-to-face encounters with video as well as audio. Sometimes it is simply not possible or practical to have a face-to-face meeting with two or more people. Sometimes a telephone conversation or conference call is adequate. Other times, an email exchange is adequate. Videoconferencing adds another possible alternative, and can be considered when:<br /> <br /> •<br /> <br /> a live conversation is needed;<br /> <br /> •<br /> <br /> visual information is an important component of the conversation;<br /> <br /> •<br /> <br /> the parties of the conversation can't physically come to the same location; or<br /> <br /> •<br /> <br /> the expense or time of travel is a consideration.<br /> <br /> Deaf and hard of hearing individuals have a particular interest in the development of affordable high-quality videoconferencing as a means of communicating with each other in sign language. Unlike Video Relay Service, which is intended to support communication between a caller using sign language and another party using spoken language, videoconferencing can be used between two signers. Mass adoption and use of video conferencing is still relatively low, with the following often claimed as causes:<br /> <br /> •<br /> <br /> Complexity of systems. Most users are not technical and want a simple interface. In hardware systems an unplugged cord or a flat battery in a remote control is seen as failure, contributing to perceived unreliability which drives users back to traditional meetings. Successful systems are backed by support teams who can pro-actively support and provide fast assistance when required.<br /> <br /> •<br /> <br /> Perceived lack of interoperability: not all systems can readily interconnect, for example ISDN and IP systems require a bridge. Popular software solutions cannot easily connect to hardware systems. Some systems use different standards, features and qualities which can require additional configuration when connecting to dissimilar systems.<br /> <br /> •<br /> <br /> Bandwidth and quality of service: In some countries it is difficult or expensive to get a high quality connection that is fast enough for good-quality video conferencing. Technologies such as ADSL have limited upload speeds and cannot upload and download simultaneously at full speed. As Internet speeds increase higher quality and high definition video conferencing will become more readily available.<br /> <br /> 154<br /> <br /> •<br /> <br /> Expense of commercial systems - a well designed system requires a specially designed room and can cost hundreds of thousands of dollars to fit out the room with codecs, integration equipment and furniture.<br /> <br /> For these reasons many hardware systems are often used for internal corporate use only, as they are less likely to run into problems and lose a sale. An alternative is companies that hire out video conferencing equipped meeting rooms in cities around the world. Customers simply book the rooms and turn up for the meeting - everything else is arranged and support is readily available if anything should go wrong. Impact on education Videoconferencing provides students with the opportunity to learn by participating in a 2-way communication platform. Furthermore, teachers and lecturers from all over the world can be brought to classes in remote or otherwise isolated places. Students from diverse communities and backgrounds can come together to learn about one another. Students are able to explore, communicate, analyze and share information and ideas with one another. Through videoconferencing students can visit another part of the world to speak with others, visit a zoo, a museum and so on, to learn. These "virtual field trips" (see history of virtual learning environments) can bring opportunities to children, especially those in geographically isolated locations, or the economically disadvantaged. Small schools can use this technology to pool resources and teach courses (such as foreign languages) which could not otherwise be offered. Here are a few examples of how videoconferencing can benefit people around campus:<br /> <br /> •<br /> <br /> faculty member keeps in touch with class while away for a week at a conference<br /> <br /> •<br /> <br /> guest lecturer brought into a class from another institution<br /> <br /> •<br /> <br /> researcher collaborates with colleagues at other institutions on a regular basis without loss of time due to travel<br /> <br /> •<br /> <br /> faculty member participates in a thesis defense at another institution<br /> <br /> •<br /> <br /> administrators on tight schedules collaborate on a budget preparation from different parts of campus<br /> <br /> •<br /> <br /> faculty committee auditions a scholarship candidate<br /> <br /> •<br /> <br /> researcher answers questions about a grant proposal from an agency or review committee<br /> <br /> •<br /> <br /> student interviews with an employer in another city<br /> <br /> •<br /> <br /> Teleseminar<br /> <br /> Impact on medicine and health Videoconferencing is a very useful technology for telemedicine and telenursing applications, such as diagnosis, consulting, transmission of medical images, etc., in real time in countries where this is legal. Using VTC, patients may contact nurses and physicians in emergency or routine situations, physicians and other paramedical professionals can discuss cases across large distances. Rural areas can use this technology for diagnostic purposes, thus saving lives and making more efficient use of health care money. Special peripherals such as microscopes fitted with digital cameras, videoendoscopes, medical ultrasound imaging devices, otoscopes, etc., can be used in conjunction with VTC equipment to transmit data about a patient. Impact on business Videoconferencing can enable individuals in faraway places to have meetings on short notice. Time and money that used to be spent in traveling can be used to have short meetings. Technology such as VOIP can be used in conjunction with desktop videoconferencing to enable low-cost face-to-face business meetings without leaving the desk, especially for businesses with wide-spread offices. The technology is also used for telecommuting, in which employees work from home.<br /> <br /> 155<br /> <br /> Videoconferencing is now being introduced to online networking websites, in order to help businesses form profitable relationships quickly and efficiently without leaving their place of work. Although it already has proven its potential value, research has shown that many employees do not use the videoconference equipment because they are afraid that they will appear to be wasting time or looking for the easiest way if they use videoconferencing to enhance customer and supplier relationships. This anxiety can be avoided if managers use the technology in front of their employees. Impact on law Videoconferencing has allowed testimony to be used for individuals who are not able to attend the physical legal settings. In a military investigation in North Carolina, Afghan witnesses have testified using videoconferencing.<br /> <br /> DEFINITION: Multimedia is woven combinations of text, graphic art, sound, and animation and video elements. When you allow an end user – the viewer of a multimedia project – to control what and when the elements are delivered, it is interactive multimedia. When you provide a structure of linked elements through which the user can navigate multimedia becomes hypermedia. A multimedia project need not be interactive to be called multimedia: users can sit back and watch it just as they do a movie or the television in such cases a project is linear, starting at a beginning and running through to an end. When users are given navigational control and can wander through the content at will, multimedia becomes nonlinear and interactive and is a powerful personal gateway to information. Multimedia elements are typically sewn together into a project using authoring tools. These software tools are designed to manage individual multimedia elements and provide user interaction. In addition to providing a method for users to interact with the project, most authoring tools also offer facilities for creating and editing text and images and they have extensions to drive videotape players and other relevant hardware peripherals. Sound and movies are usually crated with editing tools dedicated to these media and then the elements are imported into the authoring system for playback .the sum of what gets played back and how it is presented to the viewer is the graphical user interface, or GUI. This interface is just as much the rules for what happens to the user’s input, as it is the actual graphics on the screen. The hardware and software that govern the limits of what can happen are the multimedia platform or environment.<br /> <br /> 156<br /> <br /> WHERE TO USE MULTIMEDIA Multimedia is a very effective presentation and sales tool. Multimedia in business: Business applications for multimedia include presentations training, marketing advertising, product demos, database, catalogues and networked communication. THE STAGES OF PROJECT Most multimedia and web projects must be undertaken in stages. The four basic stages in a multimedia project: 1.<br /> <br /> Planning and costing: Identify how you will make each message and objective work within your Authoring system. Before you begin developing, plan what writing skills, graphic art; music; video and other multimedia expertise will be required. Develop a creative graphic look and feel, as well as a structure and navigation system that will let the viewer visit the messages and content. Estimate the time needed to do all elements, and prepare a budget. Work up a short prototype or proof of concept.<br /> <br /> 2.<br /> <br /> Designing and producing: Perform each of the planned tasks to create a finished product.<br /> <br /> 3.<br /> <br /> Testing: Always test your project whether they work properly on the intended delivery platforms and they meet the needs of your client or end user.<br /> <br /> 4.<br /> <br /> Delivering: Package and deliver the project to the end user. Hardware, software and good ideas are required to make multimedia. •<br /> <br /> HARDWARE<br /> <br /> Computers, with their graphical user interfaces and huge installed base of many millions of users throughout the world, are the most commonly used platforms today for the development and delivery of multimedia. •<br /> <br /> SOFTWARE<br /> <br /> Multimedia software tells the hardware what to do. •<br /> <br /> CREATIVITY<br /> <br /> Before beginning a multimedia project, you must first develop a sense of its scope and content.<br /> <br /> 157<br /> <br /> Mere possession of the equipment does not make one into a videographer, film editor, set designer, scriptwriter, audio engineer, animator and programmer. Some people do possess all of the innate talents required to produce decent multimedia, but few have mastered all the skills required to bring a major project to fruition. More typically world-class production are realized through the teamwork of a variety of talented people with specialized experience. Jeff burger, contributing editor ROLES: -<br /> <br /> 1.<br /> <br /> Executive producer: - works at the top-level management. He is responsible for the decisions to be implement for achievement of the objectives.<br /> <br /> 2.<br /> <br /> Project manager: - he is responsible for overall development and implementation of a project. At Microsoft project managers are called program managers. The manager has two major areas of responsibility: design & mgt.<br /> <br /> 3.<br /> <br /> Multimedia designer: - prepares the blue print of the entire project: content, media and interaction. Creates the structure for the content, determines the design elements required to support that structure and decides which media are appropriate for presenting which pieces of content.<br /> <br /> 4.<br /> <br /> Interface designer: - creates graphics for interactive multimedia tittles, a software device that organize the multimedia content and presents the content on the screen.<br /> <br /> 5.<br /> <br /> Artist: - it is a person responsible for creating designs of how of information.<br /> <br /> 6.<br /> <br /> Game design: - is a person resp for designing the games.<br /> <br /> 7.<br /> <br /> Subject matter expert: - is the head of different departments individually. E.g.: - ACCOUNTANT FOR ACCOUNTS.<br /> <br /> 8.<br /> <br /> Writer: - Multimedia writers do everything writers of linear media do; they create character, action, and point of view. They write proposals write text screens to deliver messages and they develop characters designed for an interactive environment.<br /> <br /> 9.<br /> <br /> Video specialist: - is responsible for projects requiring extensive amt of sophisticated video, a video specialist may be responsible for an entire team of videographers sound technicians, etc.<br /> <br /> 10. Audio specialist: - They are the wizard who make a multimedia program come alive, designing and producing music, voice-over narrations and sound effects.<br /> <br /> 11. Multimedia<br /> <br /> programmer: - integrates all the mfm elements of a project into a seamless whole using an<br /> <br /> authorized system or programming language.<br /> <br /> 12. Sound producer: - is a person who creates the lyrics and production work. 13. HTML coder: - integrates the multimedia elements of a project in the HTML coding or programming language. 14. Marketing director: - is responsible for the marketing activities like sales, advertisements etc. 15. Lawyer/ media acquisition: - solves all the legal matters related to the company. 16. Music composer: - compose the music.<br /> <br /> 158<br /> <br /> 17. Instruction designer/ training specialist:- are the persons who trained the persons by providing them special training sessions. TOOLS •<br /> <br /> The basic tool set for building multimedia projects contains one or more authoring systems and various editing applications for text, images, sounds and motion video. A few additional applications are also useful for capturing images from the screens, translating file formats and moving files among computers.<br /> <br /> •<br /> <br /> The tool used for creating and editing multimedia elements. Do paint and image processing, image editing drawing and illustration, 3-D and CAD, OCR and text editing, sound recording and editing, sound recording, video and movie marketing. 1.Text editing and word processing tools: -<br /> <br /> A word microprocessor is usually the first software tool computer users learn. The better the keyboarding or typing skills, the easier and more efficient will be multimedia day to day life. Word processors such as Microsoft word and word perfect are powerful applications that include spell checkers, table formatter’s thesauruses and prebuilt templates for letters, resumes, purchase orders and other common documents. In many word processors, you can actually embed multimedia element such as sounds, images and video. 2.OCR software: With optical character recognition (OCR) software, a flat – bed scanner and your computer, you can save many hours of rekeying printed words, and get the job done faster and more accurately than a roomful of typists. 3.Planning and drawing tools: Are the most important items? B’coz, of all the multimedia elements, the graphical impact of project will likely have the greatest influence on the end user. Planning software, such as Photoshop, fireworks, and painter is dedicated to producing crafted bitmap images. Drawing software, such as coreldraw, freehand, illustrator, designer, canvas, is dedicated to producing vector –based line art easily printed to paper at high resolution. Features in a drawing or painting package: •<br /> <br /> Graphical user interface with pull-down menus, status bars, palette control and dialog boxes for quick, logical selection.<br /> <br /> •<br /> <br /> Scalable dimensions, resize, stretch and distort both large and small bitmaps.<br /> <br /> •<br /> <br /> Paint tools to create geometric shapes, from squares to circles and from curves to complex polygons.<br /> <br /> •<br /> <br /> Ability to pour a color, pattern or gradient into any area.<br /> <br /> •<br /> <br /> Ability to paint with patterns and chip art.<br /> <br /> •<br /> <br /> Customizable pen and brush shapes and sizes.<br /> <br /> •<br /> <br /> Support for scalable text fonts and drop shadows.<br /> <br /> •<br /> <br /> Multiple undo capabilities, to let you try again.<br /> <br /> •<br /> <br /> Airbrushing in variable sizes, shapes, densities and patterns.<br /> <br /> •<br /> <br /> Zooming<br /> <br /> 159<br /> <br /> •<br /> <br /> Good color mgt<br /> <br /> •<br /> <br /> Good palette mgt<br /> <br /> •<br /> <br /> Good file importing and exporting capability for image formats such as PIC, GIF, TGA, WMF, JPG, PCX, EPS, PTN, BMP<br /> <br /> 4.<br /> <br /> 3-D modeling and animation tools: With 3-d modeling software, objects appear more realistic; powerful modeling packages such as AutoDesk’s discreet, strata visions 3D, secular’s logo notion and infini-D are: A good 3-D modeling tool should include the following features: •<br /> <br /> Allow to view model in each dimension<br /> <br /> •<br /> <br /> Ability to drag and drop primitive shapes into a scene<br /> <br /> •<br /> <br /> Ability to create objects from scratch<br /> <br /> •<br /> <br /> Color and texture mapping<br /> <br /> •<br /> <br /> Ability to add realistic effects such as transparency, shadowing and fog<br /> <br /> •<br /> <br /> Ability to add spot, local and global lights, to place them anywhere, and manipulate them for special lighting effects<br /> <br /> •<br /> <br /> 5.<br /> <br /> Ability to draw spline – based paths for animation<br /> <br /> Image – editing tools: Specialized and powerful tools for enhancing and retouching existing bitmapped images. These applications also provide many of features and tools of painting and drawing programs and can be used to create images from scratch as well as images digitized from scanners, video frame-grabbers, digital cameras, chip art files or original artwork files created with a painting or drawing package. Features of image- editing applications: -<br /> <br /> 6.<br /> <br /> •<br /> <br /> Capable selection tools to select portions of a bitmap<br /> <br /> •<br /> <br /> Image and balance controls for brightness ,contrast and color balance<br /> <br /> •<br /> <br /> Good masking features<br /> <br /> •<br /> <br /> Multiple undo and restore features<br /> <br /> •<br /> <br /> Color-mapping controls<br /> <br /> •<br /> <br /> Tools for retouching, blurring, sharpening, lightening, darkening, smudging, and tinting<br /> <br /> •<br /> <br /> Geometric transformations such as flip, skew, rotate, and distort<br /> <br /> •<br /> <br /> Multiple typefaces, styles, and sizes<br /> <br /> •<br /> <br /> Filters for special effects, such as crystallizes, dry brush, emboss, ripple, smooth Sound Editing Tools<br /> <br /> By drawing a representation of a sound in fine increments, whether a score or a waveform, you can cut, copy, paste, and otherwise edit segments of it with great precision- something impossible to do in real-time. System sounds are shipped with both Macintosh and windows systems and they are available as soon as you install the operating system.<br /> <br /> 160<br /> <br /> 7.<br /> <br /> Animation, Video, and Digital Movie Tools: are sequences of bitmapped graphic scenes, rapidly played back. But animations can also be made within the authoring system by rapidly changing the location of objects or sprites to generate an appearance of motion.<br /> <br /> 8.<br /> <br /> Quick Time: Quick Time is a software-based architecture for seamlessly grating sound text animation and video. Quick Time Building Blocks:Three elements make up quick time •<br /> <br /> Quick time movie file format<br /> <br /> •<br /> <br /> Quick time media abstraction layer<br /> <br /> •<br /> <br /> Quick time media services<br /> <br /> The movie file format is a container that provides a standard method for storing video, audio, and even text descriptions about a media composition. The media abstraction layer describes how your computer should access the media that is included in the quick time movie. The media services part of quick time not only has built in support for over 35 media file formats. With built in filters in movie player you can adjust colors, contrast and brightness and you can apply special effects to your composition such as film noise and edge detection. Offers a comprehensive set of “services” •<br /> <br /> Timing and synchronization<br /> <br /> •<br /> <br /> Audio and image data comprehensive and decompression<br /> <br /> •<br /> <br /> Image blitting, format conversion, scaling, composition and Transcoding<br /> <br /> •<br /> <br /> Audio mixing, sample rate conversion and format conversion<br /> <br /> •<br /> <br /> Audio and video effects and transitions<br /> <br /> •<br /> <br /> Synchronized storage read and write<br /> <br /> •<br /> <br /> Media capture<br /> <br /> •<br /> <br /> Media import and export<br /> <br /> •<br /> <br /> Standard user interface elements Unit 4<br /> <br /> Multimedia Definition: “the multimedia is a woven combination of text, arts, graphics, sound,<br /> <br /> and video elements”.<br /> <br /> TYPES OF MULTIMEDIA 1.) interactive multimedia 2.) hyper media 3.) linear multimedia 4.) non-linear multimedia 1.) Interactive multimedia: when we allow an end user to control what and when the elements are delivered then it is interactive multimedia. in this user interacts directly with any type of media.<br /> <br /> 161<br /> <br /> For example: E-Mail. 2.) Hyper media: when we provide a structure of linked elements through which the user navigates then interactive multimedia becomes hyper media. 3.) Linear multimedia: When the users can sit and watch it just as they do a movie or television then the project is linear as it is starting at the beginning and running through an end. 4.) Non-linear multimedia: when the users are given navigational control and wander through the content at will then the MM is non-linear. MULTIMEDIA PLATFORM: The H/W AND S/W that govern the limits of what can happen is known as multimedia platform or multimedia environment. MULTIMEDIA PROJECT: The S/W vehicle messages and the content presented on a computer or television screen constitute a multimedia project. (project is a S/W vehicle). USES OF MULTIMEDIA: A. Multimedia in Business: • The business application for multimedia includes presentation-training programs, marketing, auditing, project demos, and data based and networked communication. • Voice mail and video conferencing can be provided on many local and wide area network (LAN &WAN) using Ips. • It is of widespread use in training programs, the flight attendants learn to manage the international terrorism & security through simulation. • Mechanics learns to repair engines, sales. people can learn about product line. B. Multimedia in Schools: • Schools are the most needed destinations for multimedia. the part of multimedia can be maximized for the greatest long term benefit to all. • With the applications of the teachers may become more like guides not just the provider of information. • Adults & children both can learn well by exploration & delivery. • With the help of multimedia, students can make quite time movies, images etc. • The students can make art, images and graphics by using various images editing tools. C. • • D. • • •<br /> <br /> Multimedia in Homes: From gardening to cooking to home design, remedeting the multimedia has entered the home. most of the multimedia project can reach home via TV sets or with the help of in interactive Ips. Now the days, there is an increasing conversion of computer- based multimedia with entertainment & games based media. Multimedia in Public Place: In hostels, railway stations, shopping malls, museums, the multimedia will become available at standalone terminals to provide information & help. These installations will reduce the demands on traditional information booths & they can work round the clock even in the middle of night. Visual dues raised icons persuasive text is known to product effective responses.<br /> <br /> 5. VIRTUAL REALITY :- At the convergence of technology and creative invention in multimedia is VR. VR requires terrific computing horsepower to be realistic. “VR is a way for humans to visualize, manipulate and interact with computers and extremely complex data”. The visualization part basically refers to the computer generating visual, auditory clips. the images are the graphical rendering of a world within the computer. this world may be CAD model, a scientific simulation or a view into a database. the user can interact with the world and directly manipulate objects within the world. The application being developed for VR run a wide spectrum, from games to building and business planning. some applications provide ways of viewing from an advantageous perspective not possible with the real world, like scientific simulators and telepresence systems air traffic control systems. many applications of multimedia are much different<br /> <br /> 162<br /> <br /> from anything we have experienced. these may include flow of world’s financial market navigating a large corporate information based.<br /> <br /> TYPES OF VR OPERATING SYSTEMS:A major distinction of VR systems is the mode with which they interface to the user. (i) Windows on world system (WOW):-Some systems use a conventional computer monitor to display the visual world. thus is known as desktop VR or WOW. (ii) Video mapping:- A variation of the WOW approach merges a video clips of the user’s silhouette (user at will) with a 2D computer graphie. The user watches a monitor that shows his body’s interaction with the world. (iii) Mixed reality:- merging the telepresence and VR systems gives the mixed reality or seamless simulation systems. there the computer-generated clips are merged with telepresence clips and the users views of the real world. (iv) In short, we can say VR is a way for humans to visualize, manipulate and interact with computers and extremely complex data. •<br /> <br /> VR operating system:- The term VR is a specific collection of technologies, that is a head mountal display glove clip device and audio. it basically refers to the computer generating visual, auditory or other sensual operators to the user of a world with in the computer. this world may be a CAD model, a scientific simulation or views into a database. the users can interact with the world and directly manipulate objects within the world. • The applications being developed for VR run a wide spectrum from games to architectural and business planning. the various applications including the use of VR are scientific simulators, telepresence systems, air traffic control systems. • STAGES OF MULTIMEDIA PROJECT:4 Basic stages of multimedia project are:-<br /> <br /> I. II. III. IV.<br /> <br /> Planning and costing:- Before we began developing, plan what writing skills, graphics art, video and other multimedia expertise are required and after that a creative graphic look can be developed. the time needed to do all elements and then prepare a budget. then work up a short prototype. Designing and producing:- performs each of the planned tasks to create a finished product. Testing:- then we can test our programs to make sure that they meet the objectives of our project. Delivering:- package and deliver the project to the end user.<br /> <br /> REQUIREMENTS TO MAKE MULTIMEDIA:i. ii. iii.<br /> <br /> HARDWARE SOFTWARE CREATIVITY We actually need talent and skills to make multimedia. (i) Hardware: - there are two most significant platforms for producing and delivering multimedia. a) Macintosh operating system from apple b) Intel based IBM PC The basic principles for creating and editing multimedia elements are the same for Macintosh and PCs. the tools and methods used to make and display multimedia.<br /> <br /> 163<br /> <br /> (ii) Software: - The multimedia software tells the network what to do. Example: - display the color red, play the digitized movie or turn down the volume of MP3 player. There are also large numbers of software tools, which are used to work with large numbers of software tools, which are used to work with text, images, sound or video. (iii) Creativity: - Before developing a multimedia project we must firstly develop a sense of its scope and content. developers can add their own creativity touches to design their unique multimedia projects. there are certain known formulas for the success of multimedia. (iv) Organization: - It is essential that we develop an organized outline and a plan that rationally details the skills, tools and resources that will be needed for a successful project. FRAMEWORK OF MULTIMEDIA SYSTEMS: The framework basically contains of four interrelated models: -<br /> <br /> The information and distributed processing models constitute the multimedia information system (MMIS). The conferencing and multiservice network models from the multimedia communication systems. 1) MM Information model: - It includes data modeling for storage, retrieval and processing. the information also includes MM documents, presentations and other components. 2) MM Distributed processing model: - This model includes system services, application toolkits and application frameworks. 3) MM Conferencing model: - This model provides abstractions for multiparty communication, real-time interchange, E-mail and telephony. 4) MM Network model: - This model supports the communication model with a network architecture, network protocol and interfaces. the networks for di9stributed MM systems must support a wide range of traffic requirements such networks are described as multiservice. COMMUNICATION DEVICES The various MM applications are developed in workgroups. these workgroups are comprises of various designers, writers, graphics, artists, programmers and musicians. the communication among the workgroup members is essential for the successful of the project. Various communication devices: 1. Modem 2. ISDN 3. DSI Modem 4. Cable modem MULTIMEDIA AUTHORING TOOLS : These tools provide us the important framework we need for organizing and editing the elements of our MM project including sound, graphics, animations and video clips. these tools are used for designing interactively and user interface to present our project on screen. Authoring software provides an integrated environment for binding together the content and functions of our projects of our projects. with MM authoring software we can make: 1.<br /> <br /> Video production<br /> <br /> 164<br /> <br /> 2. 3. 4. 5. 6. 7.<br /> <br /> Animation Games Interactive websites Presentations Interactive training Simulations, Prototypes and technical visualizations Types of authoring tools: -<br /> <br /> 1. 2. 3.<br /> <br /> Card and page based tools icon based or event driven tools time based or presentation tools<br /> <br /> 3. Time based authoring tools: Each tool uses it own distinctive approach and user interface for managing events overtime.  <br /> <br /> Director:- Macromedia’s director is a powerful and complex MM authoring tool from Macromedia with a broad set of features to create MM presentations animations and interactive MM applications. in Director:- The elements of a project are assembled and sequenced using a cast or score.<br /> <br /> CAST:- Cast is a MM database containing still images, sound files, text, palettes, programming scripts, Quick time movies, Flash movies and other directories.<br /> <br /> 165<br /> <br /> SCORE:- Once we have imported or created the MM elements of our project and placed them into our cast, we tie these cast members together using the score facility. Actual Score is a sequence for displaying, animating and playing cast members. The score also provides elaborate and complex visual effects and transitions, adjustments of color palettes and tempo control (temporary object control). LINGO:- Directive utilizes Lingo, a full featured object oriented scripting language, to enable, interactivity and programmed control. Using lingo we can chain together separate Director Documents. VARIOUS FEATURES OF AUTHORING TOOLS:1. 2.<br /> <br /> 3. 4. A. B.<br /> <br /> 5. 6. 7.<br /> <br /> EDITING FEATURES ORGANIZED FEATURES PROGRAMMING FEATURES:- Visual Programming with icons and objects, scripting language, traditional language such as Basic or C, and document tools. INTERACTIVITY FEATURES:- Authoring tools providing one or more levels of interactivity. Simple Branching:- It offers the ability to go to another section of MM production via an activity such as key processor, mouse click. Conditional Branching:- It supports a go to based on the result of IF- Then decisions. PERFORMANCE TUNING FEATURES:- Complex MM project also require MM tunning features. DELIVERY FEATURES:- Delivering our project requires building a run time version of the project using the MM authoring software. If w want to distribute our project widely, we should distribute it in run time version. CROSS PLATFORM FEATURES: - It is also important to use tools that make transfer across platforms.<br /> <br /> BASIC SOFTWARE TOOLS The software tools are needed for creating and editing MM on both the windows and macintosh platforms for image processing, editing, drawing, text editing, sound recording making video and movie making.<br /> <br /> A.<br /> <br /> Word Processor: - The word processor is the first software tool computer users learn. it is the most often used tool when w design and build a MM project. A single word processor can share documents in shared format. The word processor comes bundled in an “office suite” which includes spreadsheet, database, E-Mail, web browser and presentation applications. B. Painting and Drawing tools: - Painting software such as photoshop, fireworks and painter are dedicated to produce crafted bitmap image. Drawing software such as Freehand, designer and canvas is dedicated to produce vectorbased art. the various color models are available as RGB, HSB and CMYK for good color management. C. 3-D modeling and animation tools: - With a 3-D modeling software objects appear more realistic. A good 3-D modeling tool should have the following: 1. Ability to drag and drop primitive shapes into a scene. 2. It should provide color and texture mapping. 3. It could add realistic effects such as transparency, shadowing and fog. 4. Ability to add spot, local and global lights to place them anywhere and manipulate them. D. Image editing tools: - These are powerful tools for enhancing the existed bitmapped images. Features are: I. Multiple windows that provide views of more than one image at a time. II. Good masking features. III. Multiple undo and restore features. IV. Image and balance controls for brightness, contrast and color balance. V. Support for third party special plug-ins. E. Video and Digital movie tools: - Digital video movies are the sequence of bitmapped graphic scenes or frames which are rapidly played back. movie making tools take the advantage of quick time for Macintosh and Windows. Movie making tools such as Premiere, videoshop are available which lets us edit and assemble video clips. MULTIMEDIA HARDWARE<br /> <br /> 166<br /> <br /> <br /> <br /> THE MACINTOSH PLATFORM: - The Macintosh we need for developing a project depends entirely upon the projects delivery requirements its content and the tools we need for production. All Macintosh can record and play sound. Many include hardware and software for digitizing and editing video preducing DVD disc.<br /> <br /> <br /> <br /> Apple introduced the first power Macintosh computers based on RISC (Reduced Instruction Set Computing) microprocessors during 1994.<br /> <br /> In 1997, the G3 series was introduced with clock speeds greater than 233 Mhz and offering high performance than existing Pentium based windows. By 2001, the G4 computers offered T33 Mhz speeds and even a dual processor arrangement with a 20 times performance increase over the G3 when running applications like Photoshop. <br /> <br /> The windows platform – unlike an Apple Macintosh computer, a Windows computer is not a computer but rather a collection of parts that are tied together by the requirements of windows OS. The various parts like Power supplied processors, video-audio components, monitors, keyboards and mike are all assembled.<br /> <br /> ADVANTAGES OF MACINTOSH VS WINDOWS/INTEL:1. 2. 3. 4.<br /> <br /> Macintosh users spend 38 fewer hours per year “futuring” with files. Save many dollars annually on support and training. Use more tools. (14.8 Vs 8.3) Achieve platform payback in 7.2 months (versus 13.9) NETWORKING MACINTOSH AND WINDOWS COMPUTERS<br /> <br /> If we are working in a MM development environment consisting of a mixture of Macintosh and windows computer then we want them to communicate with each other. We also wish to share resources among them, such as printers. • LAN and WAN can connect members of workgroups. LAN:- In a LAN the various computers are located within a short distance of one another, on the same floor of a building. LAN’s allow direct communication and sharing of peripheral resources such as file servers, printers, scanners and network modems. they use the technology like Ethernet or token ring to perform the connection. WAN:- These are the communication systems spanning great distances. these are setup and managed by large corporation and institutions for their use. WANs are expensive to install and maintain. • the various other method for long distance communication are: ISP, America online, CompuServe, MSN. SCSI:- Small computer system interface. SCSI lets us add the various peripherals equipment such a disk drivers, scanners, CD-ROM players and can connect as many devices (ID no 0 to 7) top SCSI bus, but one of them must be computer itself with ID 7 and one in the internal hard disk with ID 0.<br /> <br /> High end Macintosh had two SCSI buses, internal as well as external and so we could hook up twice as many devices. SCSI cards can be installed in PC’s and various external peripheral devices such as hard disc, CD-ROM drives, tapedrives, printers, scanners, rewritable cartridge drivers can be connected to the installed card. When a SCSI device is connected to the interface card in a PC, it is mounted to the system as another drive letter. We may have: Floppy-Drives Hard disk drives CD ROM SCSI based external device<br /> <br /> A: &B: C: &D: E: F:, G: and so on<br /> <br /> With ultra SCSI, we can hook as many as 32 devices to our computer. SCSI cabeling is very sensitive to length and resistance.<br /> <br /> 1.<br /> <br /> MS-Word: It provides the same user interface on both platforms and offer special MM features. We can make and import various image formats including PICT, TIFF, BMP and EPS to place them in our document. We can also add quick time movies toward our documents.<br /> <br /> 167<br /> <br /> 2.<br /> <br /> Word-Perfect: Word perfect for Macintosh offer a quick time movie playing facility .the movie is represented by its poster, usually the first frame of the movie. We can represent our movie as a character, anchor it to a page or paragraph, move it, add a caption etc. Using DDE, Word perfect for windows can share data with other DDE compatible programs that use DDE links. We can change retrive, save or import them into our documents. INPUT DEVICES: An input device is an electro mechanical device,which accepts data from the outside world and translates them in to a form which a computer can interpret. they can broadly classified in to : 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.<br /> <br /> Keyboard Trackball Graphics tablets or Digitizers Mouse Touch Screen Flat bed scanner Magnetic Card encoders and Readers OCR optical character recognition devices Infrared remotes Digital cameras Voice recognition systems<br /> <br /> OUTPUT DEVICES:An output devices is an electro mechanical device,which accepts data from a computer and translates them in to a form,which is suitable for use by the users.Presentation of the audio and visual components of your MM project requires hardware that may or may not be included with the computer itself-spealers,amplifiers,monitors,motion video devices and capable storage systems.The better the equipment, the better the presentation. They can be further be classified into:  AUDIO DEVICE  AMPLIFIERS AND SPEAKERS  MONITORS  VIDEO DEVICES  PROJECTORS  PRINTERS  DVD  CD-ROM IDE – Integrated drive Electronics. Advance technology attachment (ATA) connections are typically only internal and they connect hard-disks, CD-Rom drives and other peripheral mounted inside the PC. A PC motherboard can support two IDE controllers and each controller in turn can support two devices (a master and a slave). thus with IDE, we can install a combination of four hard-disks, CD-Rom drives or other devices in our PC. the circuitry for IDE is typically mush less expensive than for SCSI. LIMITATIONS OF IDE: <br /> <br /> IDE requires time from the main processor chip, any one drive in a master/ slave pair can be active at once and because a master drive manages the operation of both drives, a failure of master drive will disable both drives.<br /> <br /> IDE OF VARIOUS TYPES: • • •<br /> <br /> PLAIN IDE: - It can transfer data at 2.5 MB. Enhanced IDE: - It can transfer data at 16.4 MB per second. Ultra IDE: - It can transfer data at 33 MB/Sec.<br /> <br /> 168<br /> <br /> MEMORY AND STORAGE DEVICE: 1. 2. 3. 4.<br /> <br /> RAM – Volatile memory. ROM – Non- volatile memory. unlike RAM when we turn off the power to a ROM chip, it will not forget or lose its memory. ROM typically used in computers to hold the small BIOS program that initially boots up the program. FLOPPY DISK AND HARD DISK ZIP, JAZ, SY QUEST AND OPTICAL STORAGE DEVICES<br /> <br /> Multimedia authoring environment ORIGINS In the old days, an incredible amount of work went into the production of even the simplest multimedia title. Programmers had to know the ways of manipulating graphics and expect the hassle of dealing with a dozen different drivers. Therefore, until authoring environments have been developed many programs required the skill of a professional. The time, money, and research required to produce a multimedia title put authoring capabilities out of reach for business computer users. With the development of authoring tools the whole process become so much faster and simpler that now not only computer genus but also a non-professional without previous programming experience should all be theoretically able to learn and use the authoring environment for creating their own multimedia applications. DEFINITIONS Authoring environments let developers create applications with sophisticated interaction without or little knowledge of programming. The user can navigate by clicking objects and hot spots, choosing from groups of answers, dragging and dropping objects to make selections, and even entering free-form text or numeric responses. Authoring enables creating applications with high degree of interactivity in which information flows from application to user and from user to application. Authoring programs can be divided into two distinctive types: those that relied entirely on point-and-click and those that required simple scripting. If one never wants to write even a single line of code, he have to choose the authoring environment that does not require him to do that, an example here would be Authorware. CAPABILITIES The most advanced authoring applications available on the market, like recently released Point&Click by Corel, provide complete solutions for the creation of multimedia applications. They are designed for high performance, intuitive production, open architecture environment and portability. The authoring environment provides comprehensive tools for professionals and enables artists to create sophisticated multimedia with ease, without the need for programming. Professional programmers are able to use them for making prototype applications for the creation of more complex, high-end applications. They can be used to build corporate presentations, interactive training and education packages, screen savers and more. They are supposed to be exceptionally easy of use, with a short learning curve, but from my own experience I can say that it is not always true. Authoring environments may come together with collection fonts, clip art images, video and animations, sound effects, 3D images, 100 pre-made transition effects, games, screen savers, and tutorials ready to be used in your application thus speeding the whole process even further. It is much faster to use authoring environment as opposed to programming in compiled code. It generally takes about 1/8th the time to develop an interactive multimedia project, such as a CBT program. REQUIREMENTS Although creating applications using authoring tools does not require knowledge of programming some knowledge of heuristic thinking and algorithm design is necessary. Authoring speeds up programming by automating of most functions To be able to use authoring tools effectively understanding of how programs work is required, but the knowledge of complicated rules of a programming language is not essential.<br /> <br /> different authoring paradigms<br /> <br /> 169<br /> <br /> Most authoring packages aim at the same goal - creation of the environment providing the design tools and automating most of the programming, letting the user focus on the task; but they achieve the task in different ways. These different ways are called paradigms. A paradigm, also known as the authoring metaphor, is therefore the methodology by which the authoring system accomplishes its task. There are various paradigms, including:<br /> <br /> • • • • • • • •<br /> <br /> Scripting Language Iconic/Flow Control Frame Card/Scripting Cast/Score/Scripting Hierarchical Object Hypermedia Linkage Tagging<br /> <br /> The choice of the paradigm depends upon the task and the skills of the author: The scripting paradigm tends to be longer in development time so it takes longer to code an individual interaction,but more powerful interactivity is possible. Iconic/Flow paradigm tends to be the fastest for developing and is best suited for rapid prototyping and shortdevelopment time projects, and does not require the ability to write code. Card/Scripting paradigm is suitable for Hypertext applications, and navigation intensive productions. Many games and other entertainment applications are prototyped in a card/scripting system prior to compiled-language coding. Cast/Score/Scripting authoring style is thought to be the best suited for animation-intensive or synchronised media applications Tagging are best suited to online reference material like dictionaries and manuals Although almost all these packages are complete multimedia solutions, it is impossible for one application to cover the whole spectrum of needs. A tool that's ideal for creating hypertext, for example, may be less suitable for complex scripting or video playback. As authoring systems vary widely in orientation, capabilities, and learning curve. There are many paradigms to choose from to best suite the task and the authors capabilities.<br /> <br /> card / page authoring paradigm The metaphor for a card-based authoring tool is the organisation of multimedia content onto individual pages or cards. Buttons link one card to the next and presentations are build using templates and pre-recorded media clips. For authors familiar with PowerPoint or Freelance Graphics, card-based multimedia tools are a natural transition. The Card/Page paradigm uses a book metaphor for setting up its graphical environment that means that each scene is a page in the book, with graphics, sound, and other components placed as objects on the page. Each object, page and book can maintain its own separate script. The advantage of card-based programs is a very short learning curve. A big drawback of such applications is that to take advantage of its full potential, one needs to be fairly proficient at writing code. So although it provides a great deal of power via the incorporated scripting language but is not suited for person who has no programming experience. An example of a product that uses Card/Page paradigm is Asymetrix's Toolbook. It is a powerful tool but quite difficult to use. Gaining access to specific objects' scripts requires several elaborate keystroke combinations, and there's no easy way to see a representation of a book's graphical components. As mentioned above such a style is well suited for Hypertext applications and navigation intensive applications.<br /> <br /> 170<br /> <br /> icon / flowchart authoring paradigm FEATURES Some authoring packages rely on the mouse instead of the keyboard. They hide their scripting languages under a pointand-click interface, so the are said to be no programming required solutions. Such approach, in which the system guides you through creation of an application, is often called the wizard or icon paradigm. The organisational metaphor of an icon-based tool is a flowchart comprising icons or thumbnails that represent specific components and events within a presentation. Icon-based tools like AimTech's IconAuthor, Macromedia's Authorware Professional, and Allen Communications' Quest are classics in this genre. The core of the icon/flowchart paradigm is the Icon Palette, containing the possible functions/interactions of a program, and the Flow Line, which shows the actual links between the icons. The presentation is build by dragging icons from a toolbar onto a blank page. This document then becomes the design blueprint. ADVANTAGES Icon-based tools are especially suited for fast prototyping and for building applications that are heavy on interactivity, like computer-based training and public kiosks. These programs are industrial strength, but they can be very expensive, with price tags ranging upwards to nearly $5,000.00. This tends to be the fastest in developing authoring style. LIMITATIONS The problem with such products is that "instead of writing lines of code, the user spends a great deal of time checking options in dialog boxes, clicking buttons to load files, and selecting obscure events from list boxes". For users who are unfamiliar with multimedia production, this guidance can prove very useful but after a while of using the tool the author may decide that he needs to be more in control of the way his application is being produced. The useful feature of that paradigm is that you do not need to write any code and it is supposed to be easy to use. But it has big limitations in that it does not offer the freedom other paradigms do. DEVELOPMENTS IN COMPUTING Until recently, we used computers to process data and design printed materials; activities that improved our productivity. With desktop multimedia, we're using computers to inform, entertain, educate, or persuade an audience. As computers grow ever more powerful, it's getting harder and harder to tell where traditional software ends and multimedia begins. Video and sound clips are showing up in word processing documents, and hypertext and audio feedback are finding their way into World Wide Web sites. But there is a difference between creation multimedia application as opposed to traditional formats. The main difference results from contrast between traditional and multimedia programs, and lies at the very background of what multimedia really is. Building a multimedia application requires from the author ability to combine different types of media into a coherent unanimity. THE CHANGED ROLE OF THE AUTHOR The duties of the developer, while still burdened heavily by actual programming are now increased to include decisions that affect media planning, interface design and even traditional artist-only domains such as screenwriting. The reason for these additional responsibilities is primarily that of performance: responsiveness to the user and smoothness of delivery. In order to ensure this, highly technical issues often impact the very design of the title, dictating items such as graphic colour depth, video compression format and data rate, animation style even rough editing of voice-over narrative. THE PROCESS Creating a multimedia title is a three-step process: planning and designing the title, developing the media effects, and authoring (or producing) the final title. Authoring tools range from easy-to-use software programs that let you quickly integrate multimedia effects to programming languages that give you more sophisticated control. MAIN ELEMENTS OF MULTIMEDIA AUTHORING ENVIRONMENT While building multimedia application one has to complete a challenging task of integrating all media into a meaningful and attractive application. It is not an easy task but there are tools at hand that help us do just that. Major content-development packages are likely to include:<br /> <br /> 171<br /> <br /> • • • • • • • • •<br /> <br /> Paint programs for still images (photos, original digital artwork) Paint effects programs Illustration (draw) programs for still images (modelled and rendered objects) Video digitising/editing programs Video effects programs Audio sampling/editing programs Word processors (script and program text) Database programs Animation programs<br /> <br /> Using those tools author puts different media components into his application and the program then helps to integrate them into coherent integrated whole. Multimedia brings a new level of interactivity to the desktop. You can design a title that requires specific audience responses: navigational jumps to click, questions to answer, onscreen elements to click and drag, and so on, involving the user in new ways, and demanding attention.<br /> <br /> How to choose an authoring tool to build a multimedia application? Some multimedia packages are simple kits aimed at those who occasionally prepare business presentations, while others are formidably powerful, complex development systems. An authoring tool's role is to integrate various computer media; therefore, it should be capable of handling text, graphics, and digitised audio and video, using popular formats. An authoring package should also include some form of scripting language, if only an iconic one. The product you create with an authoring tool must be transportable without having to include the authoring tool, etc. AUTHORING TOOL CHECKLIST With so many multimedia products on the market, it can be hard to match one with your application needs.<br /> <br /> Before you decide you should ask yourself the following questions: 1.<br /> <br /> What are the system requirements?<br /> <br /> Digital video, higher colour depths and database applications require more memory than the recommended minimum. You'll need a 16MB or even a 32MB PC to do any meaningful multimedia work. 2.<br /> <br /> What metaphor does the product use?<br /> <br /> A stage with cast members, pages of a book, buttons, icons, or windows? Each metaphor imposes a certain flavour to a production, so you want to be sure to choose one that is appropriate to your way of thinking. 3. 4.<br /> <br /> Does the program support animation? Can you use the product to create original animation,<br /> <br /> or will it run only ready clips? 5.<br /> <br /> How many image and sound formats does it support?<br /> <br /> An authoring environment that supports only one or two file formats forces you to use either a separate editing program or a converter tool. 6.<br /> <br /> Does the product include image,<br /> <br /> animation, video, and sound editors, and are they user-configurable?<br /> <br /> 172<br /> <br /> 7.<br /> <br /> What support does the product provide for common multimedia elements<br /> <br /> such as buttons, list boxes, menus, dialog boxes, and cursors? Buttons should at least provide some form of visual feedback when pressed. 8.<br /> <br /> How well does the product handle text?<br /> <br /> This is important. Although picture may be worth a thousand words, a multimedia production without words is only a cartoon or slide show. Make sure that it lets you edit text in the production as well as change text on the fly. 9.<br /> <br /> Does the product support hypertext?<br /> <br /> You have to be able to make hot spots within text function as buttons, and pop-up hypertext. Most authoring products are event-driven they wait for a mouse click, a key press, a timer, or some other action to start a sequence. 10. How much control over events does the developer have with the program? Can you design custom events? 11. Does the product have an authoring language? A scripting language dramatically increases what can be done with an authoring environment. 12. Which, if any, database formats can the product access? As multimedia makes inroads into the sales and marketing communities, the ability to access and manipulate database information is becoming essential 13. How well does the general focus of the product meet your needs as a developer? No multimedia tool can ever be truly comprehensive, so look at each program's functions and strong points to pick the best one for you. LITTLE MULTIMEDIA GLOSSARY Branch Any one of the paths an application can take after it evaluates a specific condition. CBT (computer-based training) method usually used in corporations and academia to help nonpr ogrammers generate applications. Debugging Executing a program, one statement at a time, to identify and fix errors. Event handler A special type of function that executes automatically when a particular user-enabled, system-enabled, or codegenerated event occurs. Execution flow The section of code that the application executes, depending on branching decisions. Function An instruction to the application that performs operations or returns a value, or both. Hot spots Buttons or other programmable objects that can activate objects or linked events. Kiosk A centre of standalone interactive information or content. Loop A set of statements in a program executed repeatedly, either a fixed number of times or until a specified condition is true or false. MCI (Media Control Interface) A standard control interface for multimedia devices and media files, including a command-message interface and a command-string interface. MPEG A digital video standard developed by the Motion Pictures Experts Group.<br /> <br /> 173<br /> <br /> ODBC (Open Database Connectivity) support Access to the database programming interface from Microsoft Corp. ODBC provides a common language for Windows applications to interact with various databases, locally and on a network. Palette A table of available simultaneous colours that paints pixels on the screen. Score A sequence, either time-based or frame-based, that determines the timing of a presentation and the synchronisation of its objects. Sequence A combination of events executed in a predetermined order. Sprite An independent graphic object that moves freely across the screen. Time line A graphical representation of a span of time and the chronological relationship of events. Variable A named container that holds values, either numeric or text. PROJECT PLANNING: Tasks are building blocks of project management Some Tasks are prerequisites and must be completed before others begins,So planning ahead is important. Allocate an estimated amount of time to each task and place each one along a calendar based timeline. This is project plan. The process of making multimedia: IDEA ANALYSIS: Think three your ideas; you must continually weigh your purpose or goal against the feasibility and cost of production and delivery. : What is the essence of what you want to do. : How can you organize the project? : What multimedia elements will best deliver message : Do you have content material? : What L/W is available? : How much storage space is available? : How much time do you have : Distribute the final project PRETESTING: If your idea has merit take it to the next step. Define your project goal in greater detail and spell out what it will in terms of spells, content and money to meet these goals. work up a prototype of project on paper. PROTOTYPE DEVELOPMENT: This is the point at which services work at computer, building mockups and a human interface of menus and button clicks. For a prototype called a PROOF OF CONCEPT of feasibility study, select only a small portion of a large project and get that part working as it would in the final project. Test prototype on several fronts-technology, cost,market,human interface ALPHA DEVELOPMENT BETA DEVELOPMENT DELIVERY HARDWARE:H/W is the most common limiting factor for realizing a multimedia idea.Begin by listening hardware capabilities of the end users computer platform of capabilities are not enough, examine the cost of enhancement of that delivery platform and balance those results against your purpose and resources. AVAILABLE SKILLS AND SOFTWARE: List the software and skill available to your S/W Is usually necessary only for the development of the project, not playback or delivery, and should not be cost passed on the users. IDEA MANAGEMENT SOFTWARE:S/W such as inspiration,macproject,Microsoft project,designer edge,outlining programs such as MORE and spreadsheets like LOTUS 1-2-3 or EXCEL can be useful for arranging ideas and the many tasks, work items, employee resources, and cost of your multimedia project. Project management S/W tipically provide critical path method(CPM) to calculate the total duration of a project based on each identified task. program evaluation review technique(PERT) chart provide graphical representation of task relationships sharing the tasks must be completed before others can commence GNATT charts depicts all the tasks along the timeline. BUILDING A TEAM: MM is an emergency technology requiring a set of skills so broad that MM itself remains poorly defined players in this technology come from all the corners of the computer and art would as well as form a variety of<br /> <br /> 174<br /> <br /> other discipline, so if you need to assemble a team need to know what people and skills it takes to build a project building MATRIX chart is important . DESIGNING : the design part of your project is where your knowledge and skills with computer, talent in graphics art,video,and music, and ability to conceptualize logical pathways three information are all focused to create the real thing. Design is thinking,choosing,making and doing.it is shaping,smoothing,reworking,polishing,testing and editing competence in design phase is what separate amatures from professional in the making of multimedia,depending on the scope of the project and the size and style of your team,two approaches can be taken to create and original interactive multimedia design. FIRST-great efforts on story board or graphic outline,decribing the project in exact detail using work and sketches for each and every screen image,sound and navigational choices write down to specific colour and shades,style,responces,and voice attribute.this approach is particularly well suited for teem that build prototype quickly and rapidly converts them in to finished goods. SECOND-can use less detected story boards as a rough systematic guide,exerting less design sweat up front and more effort actually rendering the product at a work station. Both approaches require the same thorough knowledge of the tools and capability of multimedia,and both demand a story board or a project outline.the first approach is often favoured by clients who wish to tightly control the production process and labour cost.the second approach gets you more quickly in to the netty gritty, handsome tasks. Every multimedia project include content.it is the sluff from which you fashion your message.it is also the information and material that form the heart of your project that defines what your project is about. Test is,then test it again,that’s the unavailable rules.you must test and review your project on the website to ensure that it is bug free,accurate,operationally and visually our target,and clients requirement have been met,even if that client is you. The term Alpha and Beta testing are used by software developers to describe levels of product developers when testing is done and feedback is sought. ALPHA TESTING:remain flexible and amenable to changes in both the design and the behaviour of your project as u review the comments of your alpha tester . Alpha releases are typically for internd circulation only and a past among a select group of mock users often just the team working on the project . these versions of project are often very first working draft of your project, and u can expect them to have problems or to be incomplete. BETA releases are sent to a wider but still select audiences with the same this S/W may contain errors , bugs and unknown . it should be representative of real users and shouldn’t include persons who have been involved projects production . managing beta test feedback is eritical POLISHING TO GOLD : as u move through alpha and beta testing , than through the debugging process towards a final release u may want to use terms that indicate the current versions status of the project therefore bronze when you r closed to finish Gold when u has determined there is nothing left to change or correct and r ready to reproduce copies from your golden masters. If your completed multimedia project will be delivered to consumers or to a client who will install the project on many computers, you will need files so that they can be easily transferred from your media to the user’s platform. PREPARING FOR DELIVERY: if you’re completed MM project will be delivered to the consumers or to a client who will install the project on many computers, you will need files so that they can be easily transferred from your media to the user’s platform. Simply copying a project files to the users hard disks is often not enough for proper installation, you will need to install a special system and runtime files. WRAPPING IT UP: Packaging is an important area where sales and marketing issues extend the process of multimedia in to the real world of end users. DELIVERING ON THE WWW: The mechanics of putting a MM project on the web are trival,Delivery of your project and activation of your pages by making them available to ur intended audience on the web, whether to the general public or to the selected users. Behind a firewall, should be approached with caution. 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