Operating System

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM

Table of Contents

Page no.

Question 1…………………………………………………………………………….2

Question 2……………………………………………………………………………3

Question 3……………………………………………………………………………3

Question 4…………………………………………………………………………..3 - 6

Question 5………………………………………………………………………….6 - 8

Reference ……………………………………………………………………………9

Quest 1. What is Operating System? Give any 4 examples? Page 1

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM An operating system is the program that, after being initially loaded into the computer by a boot program, manages all the other programs in a computer. The other programs are called applications or application programs. The application programs make use of the operating system by making requests for services through a defined application program interface (API). In addition, users can interact directly with the operating system through a user interface such as a command language or a graphical user interface (GUI).

An operating system performs these services for applications: ➢ In a multitasking operating system where multiple programs can be running at the same time, the operating system determines which applications should run in what order and how much time should be allowed for each application before giving another application a turn. ➢ It manages the sharing of internal memory among multiple applications. ➢ It handles input and output to and from attached hardware devices, such as hard disks, printers, and dial-up ports. ➢ It sends messages to each application or interactive user (or to a system operator) about the status of operation and any errors that may have occurred. ➢ It can offload the management of what are called batch jobs (for example, printing) so that the initiating application is freed from this work. ➢ On computers that can provide parallel processing, an operating system can manage how to divide the program so that it runs on more than one processor at a time. All major computer platforms (hardware and software) require and sometimes include an operating system. Linux, Windows 2000, VMS, OS/400, AIX, and z/OS are all examples of operating systems.

Quest 2. What is a command interpreter? Name the operating system using a command interpreter? Page 2

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM The command interpreter (CI) is the program that acts as the interface between user and the operating system. It checks the MPE/iX commands that user enter for spelling and syntax errors. The CI then passes the command along to the appropriate system procedure for execution. Following execution, control returns to the CI, which becomes ready for another command. user can run the CI from within the editor and then enter the MPE/iX commands necessary to compile, link, and run a program. Then, by entering EXIT, user can immediately return to the editor. User can also run the CI from within the CI.

/Quest 3. Explain system call with examples? A system call is the mechanism used by an application program to request service from the kernel. A system call is a request made by any arbitrary program to the kernel for performing tasks -- picked from a predefined set -- which the said program does not have required permissions to execute in its own flow of execution. System calls provide the interface between a process and the kernel. These calls are generally available as assembly language instructions and they are usually listed in the various manuals used by the assembly-language programmers. Most operations interacting with the system require permissions not available to a user level process, i.e. any I/O performed with any arbitrary device present on the system or any form of communication with other processes requires the use of system calls.

Quest 4. Compare and contrast between Windows NT, Windows XP and Windows Vista? Windows NT ---Windows NT is a Microsoft Windows personal computer operating system designed for users and businesses needing advanced capability. NT's technology is the base for the Microsoft successor operating system, Windows 2000. Windows NT which may originally have stood for "New Technology," although Microsoft doesn't say) is actually two products: Microsoft NT Workstation and Microsoft NT Server. The Workstation is designed for users, especially business users, who need faster performance and a system a little more fail-safe than Windows 95 and Windows 98. The Server is designed for business machines that need to provide services for network-attached computers. The Server is required, together with an Internet server such as Microsoft's Internet Information Server (IIS), for a Windows system that Page 3

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM plans to serve Web pages. Windows NT Workstation: Microsoft says that 32-bit applications run 20% faster on this system than on Windows 95 (assuming both have 32 megabytes of RAM). Since older 16-bit applications run in a separate address space, one can crash without crashing other applications or the operating system. Security and management features not available on Windows 95 are provided. The Workstation has the same desktop user interface as Windows 95..

Windows XP -- Windows XP is a family of 32-bit and 64-bit operating systems produced by Microsoft for use on personal computers, including home and business desktops, notebook computers, and media centers. The name "XP" stands for experience. Windows XP is the successor to both Windows 2000 Professional and Windows Me, and is the first consumeroriented operating system produced by Microsoft to be built on the Windows NT kernel (version 5.1) and architecture. Windows XP was first released on 25 October 2001, and over 400 million copies were in use in January 2006, according to an estimate in that month by an IDC analyst. It is succeeded by Windows Vista, which was released to volume license customers on 8 November 2006, and worldwide to the general public on 30 January 2007. Direct OEM and retail sales of Windows XP ceased on 30 June 2008, although it is still possible to obtain Windows XP from System Builders (smaller OEMs who sell assembled computers) until 31 January 2009 or by purchasing Windows Vista Ultimate or Business and then downgrading to Windows XP. Windows XP is known for its improved stability and efficiency over the 9x versions of Microsoft Windows. It presents a significantly redesigned graphical user interface, a change Microsoft promoted as more user-friendly than previous versions of Windows. New software management capabilities were introduced to avoid the "DLL hell" that plagued older consumer-oriented 9x versions of Windows. It is also the first version of Windows to use product activation to combat software piracy, a restriction that did not sit well with some users and privacy advocates. Windows XP has also been criticized by some users for security vulnerabilities, tight integration of applications such as Internet Explorer 6 and Windows Media Player, and for aspects of its default user interface. Later versions with Service Pack 2, and Internet Explorer 7 addressed some of these concerns. The two major editions are Windows XP Home Edition, designed for home users, and Windows XP Professional, designed for business and power-users. XP Professional contains advanced features that the average home user would not use. However, these features are not necessarily Page 4

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM missing from XP Home. They are simply disabled, but are there and can become functional. These releases were made available at retail outlets that sell computer software, and were preinstalled on computers sold by major computer manufacturers. As of mid-2008, both editions continue to be sold. A third edition, called Windows XP Media Center Edition was introduced in 2002 and was updated every year until 2006 to incorporate new digital media, broadcast television and Media Center Extender capabilities. Unlike the Home and Professional edition, it was never made available for retail purchase, and was typically either sold through OEM channels, or was pre-installed on computers that were typically marketed as "media center PCs".

Windows Vista -- Windows Vista (pronounced /ˈvɪstə/) is a line of operating systems developed by Microsoft for use on personal computers, including home and business desktops, laptops, Tablet PCs, and media center PCs. Prior to its announcement on July 22, 2005, Windows Vista was known by its codename Longhorn.[3] Development was completed on November 8, 2006; over the following three months it was released in stages to computer hardware and software manufacturers, business customers, and retail channels. On January 30, 2007, it was released worldwide,[4] and was made available for purchase and download from Microsoft's website.[5] The release of Windows Vista came more than five years after the introduction of its predecessor, Windows XP, the longest time span between successive releases of Microsoft Windows. Windows Vista contains many changes and new features, including an updated graphical user interface and visual style dubbed Windows Aero, improved searching features, new multimedia creation tools such as Windows DVD Maker, and redesigned networking, audio, print, and display sub-systems. Vista also aims to increase the level of communication between machines on a home network, using peer-to-peer technology to simplify sharing files and digital media between computers and devices. Windows Vista includes version 3.0 of the .NET Framework, which aims to make it significantly easier for software developers to write applications than with the traditional Windows API.

Quest5. Elaborate upon the need and working of the following networking devices:- router, hub, bridge and switch? Page 5

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM Router – A router is a device or a piece of software in a computer that forwards and routes data packets along networks. A network router connects at least two networks, commonly two LANs or WANs or a LAN and its ISP network. A router is often included as part of a network switch. A router is located at any where one network meets another, including each point-of-presence on the Internet. A router has two key jobs: The router ensures that information doesn't go where it's not needed. This is crucial for keeping large volumes of data from clogging the network. The router makes sure that information does make it to the intended destination. In performing these two jobs, a router joins the two networks, passing information from one to the other and, in some cases, performing translations of various protocols between the two networks. It also protects the networks from one another, preventing the traffic on one from unnecessarily spilling over to the other. This process is known as routing. Routing is a function associated with the Network layer (layer 3) in the Open Systems Interconnection (OSI) model. Routers use network layer protocol headers, such as IP header where the source and destination addresses are included, and routing tables to determine the best path to forward the packets. For the communication among routers and decide the best route between any two hosts, routing protocols such as ICMP are used.

Actually, routers are specialized computers that send messages speeding to their destinations along thousands of possible pathways. One of the tools a router uses to decide which path a packet should go is a routing table. A routing table contains a collection of information, including. ➢ Information on which connections lead to particular groups of addresses ➢ Priorities for connections to be used ➢ Rules for handling both routine and special cases of traffic

Hub -- Network hubs are used to connect multiple workstations for routing through a single link to a server. In computer network systems, hubs, switches, repeaters, and routers are used when creating a network. As is well-known in local area networks, computers may be connected to each other to enable them to communicate by way of a hub. Data signals sent from a transmitting component to a receiving component are transmitted to the hub and repeated at the hub for transmission to the receiving component. The network hub enables multiple computers, Page 6

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM workstations, or file servers to share resources in a variety of applications. The simplest form of communications hub is what is known as a network repeater. Any communications sent by a computer would therefore be received by the repeater. The repeater simply retransmits any communication received on any port to all of the other ports, thereby enabling the communication to be received by all the other computers connected to the repeater. A typical network hub includes one or more devices for routing data transfers between a number of ports in a workgroup. Each port may be assigned to one or more individual users or one or more individual computers, workstations, or servers. Hubs typically have a limited number of input ports, so the number of workstations that can be connected is limited as well. To increase the number of ports available to a workgroup, multiple hubs may be connected. A network hub includes several attachment slots to hold line cards. Each line card contains one or more network devices attached to the hub. Internal data path resources within the hub are used to pass data between the multiple line cards. Hub connections are typically achieved by uplink cables, such as unshielded twisted pair (UTP) cables, shielded twisted pair (STP) cables, or fiber optic cabling. Bridge -- A network bridge is a transmission device for carrying out bidirectional data transmission across a plurality of networks connected via ports. The function of the bridge is to monitor frames transferred over the LAN and to transfer them from one network to another on the basis of the physical address of the data packets. Only frames having a destination address indicating transmission to the side of the other network are able to cross the bridge. The bridge thus acts as an insulator which reduces the load in other network portions. A LAN bridge interconnects a LAN with one or more other LANs, through an interconnecting link or links, to form a larger network in which messages can be sent from a device on one LAN to one or more devices on another LAN. Each network bridge and router requires certain other peripheral circuitry to support it such as LAN controllers, a CPU, a power supply, a network management process, memory to store bridge source and destination address tables and various other things like status registers etc. Typically, a network bridge is connected to a hub by a separate local area network segment which itself requires two port interface circuits such as LAN controllers and AUI's (generic network interfaces) with appropriate port drivers adapted for the specific media used for the bridge-hub LAN segment. Switch -- A network switch is a device that provides a switching function in a data communications network. Data communication in a computer network involves the exchange of Page 7

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM data between two or more entities interconnected by communication links and subnetworks. A network switch is an intermediate station which interconnects the communication links and subnetworks to enable transmission of data between the end stations. Switching involves transferring information, such as digital data packets or frames, among entities of the network. A switch functions as an interchange and provides path switching for data being transported over a network. Typically, a switch supports one network protocol (e.g. Ethernet), meaning that the switch manages data in a particular format. Switched local area networks use a network switch for supplying data frames between network stations or other network nodes (such as routers or gateways), where each network node is connected to the network switch by a media. A network switch for routing packets between network buses includes a set of input switch ports for receiving packets arriving on the network buses, a set of output switch ports for forwarding packets outward on the network buses, and a switch fabric for routing packets between the input and output switch ports. Each input switch port includes a memory for storing packets arriving on a network until the switch fabric can forward them to an output switch port. The input port may convert each packet arriving on a network bus to a sequence of cells of uniform size which can be efficiently stored in uniformly-sized buffer memory storage locations until the input port can forward them in proper sequential order through the switch fabric to one of the switch's output ports. Each output switch port may also include a memory for storing packets it receives via the switch fabric until the port can forward them outward on a network bus. Each output switch port stores each cell sequence arriving from an input port in its own buffer memory. The output port later reassembles them into the packet from which they were derived, then forwards the packet outward on another network bus.

Reference:www.google.com.my www.wikipedia.com www.electronics-manufacturers.com books.google.com.my/books Page 8

INDIVIDUAL ASSIGNMENT OPERATING SYSTEM searchnetworking.techtarget.com http://searchcio-midmarket.techtarget.com

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