A+ Notes

Installation Configuration And Up-Gradation Monitor Monitor is the standard out put device of computer. It came into four main types and according to paper the standard refresh rates with color support is very important. CGA (Color Graphic Adapter) EGA (Enhanced Graphic) VGA (Video Graphic Adapter) SVGA (Super Video Graphic Adapter) Monitor CGA EGA VGA SVGA

Color Support 4 COLOR 64 COLOR 256 COLOR 16 MILLION

Sync Frequency 640*200 640*350 640*480 800*600normally 1280*1024

Storage Devices Hard Disk Drives HDD is the permanent storage media. It is consists of cylinders tracks sectors and heads. One sector size is 512byte. Same sectors of plates are called cylinder. HDD cable is consists of 40 pins. HDD attached on the motherboard on built in IDE\EIDE. IDE (Integrated Drive Electronics) Integrated drive electronics (IDE) is a generic term to any drive with an integrated (Built in) disk controller. The IDE interface as we know it is officially called ATA (AT Attachment), and is an ANSI standard however, IDE can roughly apply to any disk drive with a Built-in controller. Enhanced IDE (ATA-2 and ATA-3) ATa-2 and ATA-3 are extensions of the original ATA (IDE) specification; the most important additions are performance-enhancing features such as fast PIO and DMA Modes. ATA2 also features improvements in the identify drive command allowing a drive to tell the software exactly, what its characteristics are; this is essential for both plug and play and compatibility with further revisions of the standard. NOTE: - ATA-3 doesn’t define any faster modes. ATA-3 also a simple password-based ATA-3 adds improved reliability, especially of the faster mode 4 transfers; security scheme, more sophisticated power management and self-monitoring analysis and support technology (SMART). This allows a drive to keep track of problems that might result in a failure. There are four main areas where ATA-2 (EIDE) ATA-3 and ATA-4 has improved the original ATA/IDE interface in several ways.  Increased maximum drive capacity.  Faster data transfer.  Secondary two devices channel.  ATAPI (ATA program interface)

INCREAED MAXIMUM DRIVE CAPACITY ATA-2/EIDE allows for increased drive capacity over the original ATA/IDE specification. This is done by enhanced BIOS, which makes it possible to use hard disk exceeding the 504M barriers. FASTER DATA TRANSFER ATA-2/EIDE and ATA-3 define several high performance modes for transferring data to and from the drive. The PIO () mode determines how fast data is transfer to and from the drive. In the slowest possible mode, PIO mode, the data cycle time can’t exceed 600(ns). In a single cycle, 16 bits are transferred in to or out of the drive making the theoretical transfer rate of PIO mode (600ns cycle time) 3.3m/sec. Most of the high performance ATA-2 (EIDE) drives today support PIO mode 4, which offers a 16.6m/sec transfer rate. The following table shoes the PIO modes with their transfer rate. PIO mode Cycle Time (ns) Transfer Rate (m/sec) 0 600 3.33 1 383 5.22 2 240 8.33 3 180 11.11 4 120 16.67

Specification ATA ATA ATA ATA-2 ATA-2

To run in mode 3 or 4 requires that the IDE port on the system be a local bus port this means that it must operate through either a VL-Bus or PCI Bus connection. Most motherboards with ATA-2/EID support have dual IDE connectors on the motherboard. ATA-2 and newer drives also perform Block Mode PIO, which means that they use the Read/Write/___multiple commands that greatly reduce the number of interrupts, sent to the processor. LBA (Logical Block Area) LBA is a name of addressing sector addresses, Beginning at cylinder 0, Head 0, sector 1 as LBA O, and proceeding on to the last physical sector on the drive. This is new in ATA-2, but has always been the one and only addressing mode in SCSI. With LBA, each sector on the drive is numbered starting from 0, The number is a 28bit binary number internally, which translates to a sector number from 0 to 268,435 and 456.because each sector represents 512 bytes, this result in an maximum drive capacity of exactly 128G, or 137 billion bytes unfortunately, the operating system still needs to a translate CHS, So the BIOS determines how many sectors there are, and comes up with translated CHS to match. The BIOS CHS limits are 1024 cylinders, 256 heads and 63 sectors per track, which limits total, drive capacity to just fewer than 8G. Floppy Disk Drives Floppy disk drives are used 34 pins data cable. It came in market in following models… Size 5.25 inches 5.25 inches 3.5 inches 3.5 inches 3.5 inches

Capacity 360 KB 1.2 MB 720 KB 1.44 MB 2.88 MB

Compaq Disks This is the latest model of small storage devices. It increases the capacity at 640mb normally and above. CD-Writers are now commonly to take the backup of routine data. Tape Drives Tape drives are used normally for backup the data and in it there is used magnetic tape. Tape drive has the expiry date so it should be changed before expiry date. Zip Drives ZIP drive is the latest model of storage devices that are used to transfer the data from one computer to another. The advertising companies mostly use it because they used to carry the data above 50MB. ZIP drive came normally in 50,100MB. It is like FDD but not used the tape in it; there are the plates on it. DVD (Digital Video Disc) The future of CD-Rom is called DVD. This is a new standard that dramatically increase the storage capacity of and therefore the useful applications for CD-Rom-size disks. A CD-Rom can hold may many up-and-coming applications. Especially where the use of video is concerned. One of the primary applications envisioned for the new DVD standard id a replacement for videotapes. DVD drives are also very fast compared to current CD-Rom technology. the standard transfer rate is 1.3m/sec, which is approximately equivalent to that of a 9X CD-ROMs drive. DVD drives use either the IDE/ATA or SCSI interface, just like CD-ROMs and include audio connectors for playing audio CDs through headphones or speakers. DVD-RAM is a rewritable drive type that uses phase-change techniques like that of CDRW. DVD-RAM disk can’t be read by standard DVD ROM drives because of difference in both reflectivity of the medium and the data format. Modem Modem is an IO device that is used to dial out on a remote server or in easy words it is used to connect on Internet. Modem performs two basic jobs… Modulation When data is transmitted out from the modem it performs modulation. It is basically the conversion of parallel data into serial format. Modem converts the computer’s digital data in to analog for the telephone line. De-modulation When data is received from the outside of compute it is de-modulation. It is basically the conversion of serial data into format parallel. In this state modem reverts the analog data in to digital format for computer.

Internal Modem Internal modem plugged on the expansion slot that is given on the motherboard. It may be ISA, EISA or PCI. Internal modem uses the IRQ that is available of COM PORT. External Modem External modem did not attached on expansion slot; it is attached with serial port built on the back of the motherboard. If external modem used COM 2 the COM 4 will be unavailable. If external modem used COM 1 the COM 3 will be unavailable. UART (Universal Asynchronous Receiver / Transmitter) UART chip is used to convert the parallel data into serial and serial into parallel. This chip is built on the modem and in built in motherboards situated on the board. There are available standards of UART chip as follows… Slow and no receiver and transmitter buffer 8250 One interruptible register of 9600bps 8250A 9600bps receiver and transmitter buffer 8250B 1 byte receiver and transmitter buffer 16450 16550A 16 character receiver and transmitter buffer with FIFO buffering that allow multiple DMA 16550 16750

channels at 115kbps 32byte buffer 230kbps and 460kbps specially on ISDN 64byte receiver and transmitter buffer

Modem Modulation Standards and Transmission Rates Bell Labs and CCITT (Consultative Committee On International Telephone and Telegraph) are two bodies that maintain the standard of modem protocol but now with new name ITU (International Telecommunication Union) in 1990 it works. Newly developed protocols are come with ITU-T standards. Protocol Bell 103 CCITT V.21 Bell 212A ITU V.22 ITU V.22bis ITU V.23 ITU V.29 ITU V.32 ITU V.32bis ITU V.32fast ITU V.34 ITU V.90

Maximum Transmission Rate (Bits per second) 3000bps 3000bps 1200bps 1200bps 2400bps 1200/75bps 9600bps 9600bps 14400bps 28800bps 28800bps 56000bps

Software and Hardware Modem There is the chip difference in software and hardware modem.

Duplex Mode Full Full Full Half Full Pseudo-Full Half Full Full Full Full Full

Software modem is not physically 56k but logically with the support of software it is 56k. Hardware modem physically 56k modem. Input Devices Key Board Mouse Mike Scanner Output Devices Monitor (Standard Console) Speaker Printer System Resources IRQ’s, DMA’s and I/O addresses IRQ (Interrupt Request)  IRQ is the request to the processor from the device.  When any body wants to communicate with other device first of all it requests to the processor.  The request to the processor is called interrupt request.  In XT computers IRQ’s were 0-7.  In AT computers IRQ’s 0-7 are already present and 8-15 add new. Standard IRQ Settings IRQ NUMBERS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

DESCRIPTION System Timer Keyboard Cascade to 9 Com 2 and 4 Com 1 and 3 LPT 2 Floppy Drive Controller LPT 1 Mouse Cascade as 2 Free Free Real Time Clock Math Co Processor Hard Disk Drive Controller 1 Free

IO addresses IO addresses are the addresses on that the data is to be transferred. Standard I/O Settings IO Addresses Description 1F0-1F8 Hard Drive Controller 16Bit ISA 200-20F Game Control 201 Game I/O 278-27F Parallel Port (LPT2) 2F8-2FF Serial Port (COM2) 320-32f Hard Drive Controller 8Bit ISA

378-37F 3B0-3BF 3D0-3DF 3F0-3F7 3F8-3FF

Parallel Port (LPT1) Monochrome Graphic Adapter Color Graphic Adapter Floppy Controller Serial Port (COM1)

DMA Channels (Direct Memory Access) DMA is the data communication by bypassing the processor. DMA channels are the dedicated hardware that is used to communicate the devices among the board fastly by bypassing the CPU. The sound card must use the DMA channel. Installation and configuration IDE/EIDE devices On motherboard there is two built in IDE/EIDE available each support two devices. Its mean one IDE/EIDE supports two IDE/EIDE devices on it. HDD attached on it with a ribbon cable that has three connectors on it. One attached on the motherboard and remaining two are used to attach the IDE/EIDE devices. Primary/Secondary On motherboard there are two IDE/EIDE. IDE 1 and IDE 2. IDE 1 said to be the primary and IDE 2 is said secondary. Master /Slave On each cable there are two devices can be attached first is called Master and second is Slave. On primary IDE HDD are primary master and primary slave. On secondary IDE HDD are secondary master and secondary slave. The identification of both devices should never matched with each other they must be different. Installation and configuration SCSI devices Types of SCSI Devices SCSI type Bus SCSI I 8-Bit SCSI II Fast 16-Bit SCSI II Fast Wide 16-Bit SCSI III Double Speed SCSI 16-Bit SCSI III Wide Fast-20 16-Bit SCSI III Wide Ultra 16-Bit

Data transferring speed 5 Mega Bytes per second 10 Mega Bytes per second 20 Mega Bytes per second 40 Mega Bytes per second 40 Mega Bytes per second 40 Mega Bytes per second

Cabling Internal SCSI devices used 50-pin ribbon cable that is similar to IDE cable. External SCSI used the female DB-25; Centronics-50, Mini-50 or Mini-68 connectors are used to attach it. It uses short thin and shielded cable. (SCSI should be terminated both sides) Cable Type

Connector "Alternative"

Connector Type

Contacts

Cable Name

External

Internal

1

High Density

50

External High Density "A" Cable

2

Centronics

50

External Centronics "A" Cable

3

High Density

68

External High Density "P" Cable

4

VHDCI

68

External Very High Density "P" Cable

1

High Density

50

Internal High Density "A" Cable

2

Regular Density

50

Internal Regular Density "A" Cable

3

High Density

68

Internal High Density "P" Cable

4

SCA

80

(n/a)

System optimizing Memory

Motherboard/Processors/Memory CPU Chips Processor/CPU Processor is the only component in computer that allow all processing for it. Without processor chip computer is dead. Processor came in two main types of manufacturing till now.

DIP In this type of chip processor has only two lines of pins on it.

PGA In this type of chip processor has 4 line pins on it. The processor makes all processing so it is called the central processing unit. Popular CPU Chips Chip Characteristics Motherboards

System Board System board, motherboard or planner board is the same thing. It is the primary part of a computer on that all devices are attached. AT AT motherboards are mostly found in generation of p1 motherboards. These motherboards are identifying through their processor sockets. So it is quite important that you have the idea about processor socket have AT and ATX boards. ATX/NLX

ATX/NLX motherboards are the new generation boards Comparison of Form Factors This table is a summary comparison of the sizes of the various motherboard form factors, and compatibility factors. Style

Width

Depth

Where Found

Match to Case and Power Supply

Full AT

12"

11-13"

Very Old PCs

Full AT, Full Tower

Baby AT

8.5"

10-13"

Older PCs

All but Slimline, ATX

ATX

12"

9.6"

Newer PCs

ATX

Mini ATX

11.2"

8.2"

Newer PCs

ATX

LPX

9"

11-13"

Older Retail PCs

Slimline

Mini LPX

8-9"

10-11"

Older Retail PCs

Slimline

NLX

8-9"

10-13.6"

Newer Retail PCs

Slimline

Power Supply Power supply is the only component in computer that provides the power to the motherboard. Power supply provides the volts to the computer according to its requirement. Power supply’s main function is to convert the wall outlet’s AC volts in to DC. It is perform by the diodes in power supply. Volts used by computer Computer used ±5, ±12 and ±3.3 Volts Dc current. Power supply has two main types… (Every type of power supply has the connectors for CD-ROM, FDD and HDD) AT

At power supply has two connectors names p8 and p9 to attach with the At motherboard. It consists of 6pin each. They are attached such a manner that black wires on both connectors facing each other. AT power supply have the hard switch to turn computer off and on. ATX/NLX

ATX power supply has only one connector to attach the motherboard that has 20 pins and can be attached only in one manner. ATX power supply has the soft switch to turn computer on and off. This feature must be supported in the motherboard’s ROM BIOS chip so it can work the auto power off when you shut down the pc from windows.

The main confusion of ATX power supply is that Windows NT has no support for ATX so you have to turn off the computer manually after shutting down. The ATX power supply is shut down after pressing the 5 seconds of its switch. You press the switch and after 5 seconds it turns off. Form Factors of Power Supply Form Factor

Typical Dimensions (W x D x H, mm)

Usual Style(s)

Motherboard Connectors

Match to Case Form Factor

Match to Motherboard Form Factor

PC/XT

222 x 142 x 120

Desktop

AT Style

PC/XT

PC/XT

AT

213 x 150 x 150

Desktop or Tower

AT Style

AT

AT, Baby AT

Baby AT

165 x 150 x 150

Desktop or Tower

AT Style

Baby AT, AT, AT/ATX Combo

AT, Baby AT, AT/ATX Combo

LPX

150 x 140 x 86

Desktop

AT Style

LPX, some Baby AT, AT/ATX Combo

LPX, AT, Baby AT, AT/ATX Combo

ATX/NLX

150 x 140 x 86

Desktop or Tower

ATX Style

ATX, Mini-ATX, Extended ATX, NLX, microATX, AT/ATX Combo

ATX, Mini-ATX, Extended ATX, NLX, microATX, FlexATX

SFX

100 x 125 x 63.5 *

Desktop or Tower

ATX Style

microatx, FlexATX, ATX, Mini-ATX, NLX

MicroATX, FlexATX, ATX, Mini-ATX, NLX

WTX

150 x 230 x 86 (single fan) 224 x 230 x 86 (double fan)

Tower

WTX Style

WTX

WTX

Memory Memory of computer is consists of two basic type of memory that is… RAM (Random Access Memory) Ram is called the working area for computer. It is the most important part of pc. Without Ram there is nothing to do in computer. Processor’s all processing is placed in Ram. Whenever any program is executed the Ram assigns a certain amount of block to it and then processor process the data at that place. Ram has three popular physical modules as follows… Physical Types of RAM Module SIP and DIP SIP and DIP are the oldest memory modules used in computers. These modules have the pins that are soldered on the motherboard. This was the starting of computer’s RAM. It is not included in course and has no need to go in deep. SIMM\SIPP (Single Inline Memory Module\Single inline Pin Package)

SIMM is also called SIPP because of it was the first memory module that has no directly soldered on the motherboard. It has pins and placed on the given memory bank on the board.  SIMM has come in two modules that have 30 and 72 pins.  SIMM operates at ± 5 and ± 5.5 volts.  SIMM is placed at 45 angles on the memory bank.  Memory controller chip is embedded on one side of module.  SIMM module is commonly found in 33,66 and now some chips came with 100Mhz. DIMM (Dual Inline Memory Module)  DIMM has 168 pins.  Operates at ± 3 and ± 3.3 volts.  Is placed at 90 angles on the memory bank.  Memory controller chip is embedded on the both side of module.  DIMM module came in 66, 100 and 133Mhz. RIMM (RAM Bus Inline Memory Module)  RIMM has 168 pins.  RIMM operates at ± 0.05.  RIMM is placed at 90 angles on the memory bank.  Memory controller chip is embedded on the both side of module.  RIMM has its own 2-byte data bus on the RAM chip.  RIMM logically divides the RAM in to two parts. One for Row another for column.  Clock speed of RIMM is 800 MHz and 1.2Ghz are available.  It is not hardware compatible with DIMM. Logical Parts of RAM SRAM SRAM is that portion of RAM that has no need to be refreshed. SRAM normally held the operating system and those operational materials that are need to start and run the computer at every time.  SRAM’s refreshing rate is too low then the DRAM.  SRAM has more costly then the DRAM.  SRAM obtain less power to run.

DRAM DRAM is that part of RAM where computer programs are operated. This portion of RAM has continuously refreshing and its refresh rate is in neon seconds. This portion has the information about running programs, when they start what portion is allocated to that, when it is ends and when new program starts.  DRAM consumes more energy then the SRAM.  DRAM is less costly then the SRAM.  DRAM is slower then the SRAM.  In DRAM 32 transistors work on behalf of every bit and to stay the energy they have capacitors.

 This is basically the dynamic portion of RAM that has more power and slow working. FPRAM  Fast page Ram is working logically in pages so it can access the data quickly.  FPRAM’s latency rate is 5-3-3-3.  It separates the row and columns in such a way that the row has been same and the column is changed so one sided time is saved by fixing the row.  FPRAM is the type of DRAM that works in change architecture. RDRAM    

It is the Ram Bus Dynamic Ram introduced with RIMM. It has 2-byte wide data bus. Came with two divided logical parts of Ram, one is for Rows and other for columns. RDRAM is the memory architecture for next coming generation.

ROM (Read only Memory) This is the memory type that built by the manufacturer, end user cannot change it. It requires special equipments and technical person. ROM is a chip built on motherboard and called the firmware. It has software in it… BIOS CMOS POST There are types of ROM came market till now. EPROM (Erasable Programmable Read Only Memory) This type of Rom can be reprogrammed with special equipment called BIOS WRITER. EEPROM (Electrical Erasable Programmable Read Only Memory) This Rom can be erased by the electric shots and reprogrammed with BW. UVROM (Ultra Violet Read Only Memory) UVROM is erased with the ultra-violet rays. FLASH ROM Flash Rom is the Rom of new generation that can be easily erased or upgrade with the software. Just a floppy can reprogrammed or upgrade the BIOS. Firmware ROM BIOS CHIP It is a hardware chip and also contains software in it so called the Firmware. There are the software found in chip… BIOS (Basic Input Output System) BIOS is that part of Rom that has defined the limitations of motherboard. It defines how many HDD can attaché on that board. Can this board support booting from CD-Rom or not. So this part of software allows the limitations in which you have to do your work. CMOS (Complementary Metal Oxide Semiconductor) The used defined settings are stored in CMOS.

If you change the boot sequence it change here but the part that allow you to change is BIOS. You must save the CMOS for completing the task and save your settings. POST (Power On Self Test) When computer boots up it check the system for all hardware, this is done by software called POST. It generates the errors if did not find something and also generates the beeps.

Safety And Preventive Maintenance Preventive maintenance procedure and product Manufacture Suggested Guideline Manufacturer suggested guideline is much necessary for trouble shoot or to start work on any equipment. It will guide you through the all compatibilities, exceptions and limitations of device. Liquid Cleaning Components Manufacturer document is much necessary to choose the cleaning component for a specific device. Isopropyl alcohol and denatured alcohol are commonly used for cleaning contacts and applied to clean the FDD heads. Mild detergent is used to clean the body of monitor from outside. Cleaning Contacts and Connectors Pencil rubber and isopropyl alcohol is used to clean the connectors and contacts of cards. Cleaning Tools Compressed air is used to clean the equipments from dust. Floppy Drive and Tape Head Cleaning

You are recommended to use the FDD cleaner or head cleaner for tape drive. Some cleaner floppies have the some isopropyl alcohol drops on the floppy and then cleaned the read\write head. Hard Drive Maintenance You are recommended only following HDD maintenance tools… Defragmentation Used to make the cluster in contagious form and makes the HDD performance better. Scandisk Scan disk check the HDD for errors, it scan the physical bad sectors and repair them. It marks the physical bad sectors. Scandisk can scan the compressed drive. Check disk Check disk is also works like scan disk but cannot repair the compressed drive and cannot check the physical bad sectors. It is used to check the HDD logically.

Vacuuming You should vacuum the inside of case whenever open it. The dust is sucked by the components and they get hot and may cause some serious problem.

Environmental hazard protection

Power Issues  Brownout It is referred to a device that is damaged with the cause to power disturbance but did not damaged completely. It works less then its capacity.  Blackout Complete damage of computer equipment is called the blackout.  Power Surge Power surge is the continuous powered OFF and ON.  Power Spike Power spike is the sudden increase in power for just seconds. It can burn computer equipments. UPS (Uninterruptible Power Supply) It is used to prevent your computer from sudden lapses in power that may be power surge or spikes.  UPS is consists of several components like suppressors, noise filters and surge protector.  Suppressors are used to prevent system from the power spikes. It absorbs the extra power.  Noise filter is used to prevent computer from noise and EMI. Laser and high voltage equipments Lasers There is strictly recommended that do not look directly to the laser beam. It is in CD-ROM but did not have more intensity and not harmful. Laser printer the level 3 laser beam and generates more heat, so it can be harmful to you, so be careful when you are working inside it. High Voltage Equipments Never wear a wrist strap when working on high voltage equipments. Never used both hands to working such equipments. Keep the manufactures documentation in front when using high voltage equipments. Power Supply Power supply’s main function is the conversion of AC into DC volts; during this process it generates much heat. So be careful about the fan of power supply that it must be in running form. When working on power supply give him time to cool down. CRT (Cathode Ray Tube) Monitor is high-voltage equipment so an experienced person should repair it. Never wear the Wrist strap while working on CRT. It is important that wait for 1 hour when start working on monitor.

Discharge of monitor With Screwdriver disconnect the anode lead. Use jumper wire with screwdriver and nod conductive handle. Disposal procedure Disposal of all following items should be according to the local environmental authority or law. You should follow the manufacturer’s guideline while dispose these following items.  Batteries  Toner Kits/Cartridge  Computers  Chemical Solvents  CRT, s  MSDS (Material Safety Data Sheet) United state department of occupational safety and health administration ESD (Electrostatic discharge) Your computer equipments have less charge but you have more. When we touch these equipments they may be caught defect by transferring our charge into them it is called ESD. Common ESD protection Device and Procedure You should use the ESD Wrist Strap that provides the safety for your computer equipments. It contains the 1-mega ohm resistor in it. One side of strap must be grounded. Hidden ESD It can be the cause of serious damage for the computer due to dust and dirt.

Environment for PC Humidity level should be 50 to 70% in room where system is working. Cool and dry season is more harmful for the computer and more ESD generates in it. Difference between ESD & EMI

Electro Static Discharge

Electro Magnetic Interface

It is permanent It is non recoverable It is cause by the energy transferred in to equipments

It is temporary It is recoverable It can be the cause by noise

Potable Systems Portable system, mobile systems or laptops is the same thing. The computers that can be carried somewhere. Mobile systems has two basic types… The original portables were called luggable. Although they were smaller than desktop computers they were not truly convenient to transport. The first portables included small, built-in CRT displays and detachable keyboards. The battery and CRT equipment made them extremely heavy to carry. Therefore, they never really had a major impact on the PC market. There should be the lightweight of that system so it can easily carry.

Laptop Standard laptop has only had standard devices that are attached with a mobile machine. It has no support for PC standard devices that you only can use the laptop’s devices not your standard computer devices. If you want to use your standard keyboard mouse and monitor with mobile system you had to attach a port replicator, this is a device or connector used to attach the standard devices with laptop. Docking Station Docking station is the form of laptop but only the difference is that, it supports the you’re standard computer devices attached on the back of laptop. You can use standard monitor mouse and keyboard with laptop; this is also called the built-in ports for standard devices.

Note Book Additional advancements in IC technology enabled the PC’s circuitry to be reduced further so that the unit could achieve sizes of 8.75"d´11"w´2.25"h and beyond. Portables in this size range are referred to as notebook computers. Notebook designers work constantly to decrease the size and power consumption of all the computer’s components. Special low-power consumption ICs and disk drives have been developed to extend battery life. The most widely used notebook keyboard is the 84-key version. The keys are slightly smaller and shorter than those found in fullsize keyboards. A number of keys or key functions may be combined or deleted from a notebook keyboard. Battery types and installation Mobile system are carried on the field so they have an energy media with them so they can powered on during working is called Battery. There are three different types of batteries used in mobile computers…

Nicad (Nickel Cadmium Battery)  It is the cheapest battery used in mobile systems.  It has a limit of recharging only 1000 times, after this limit it is dead.  It has memory effect so loose its actual capacity.  Memory effect • When you recharge battery after 20% of it’s remaining. Nicad battery first uncharged that 20% then recharge it from 0%. During this process some area of battery become dead. It is only happened in Nicad battery.  Nicad is the oldest model of batteries.  It takes more time for full recharging as much as 12 hours.  It is necessary for Nicad battery that I should be recharge after complete discharging. Nimh (Nickel Metal Hydride Battery)

 It is better then Nicad.  It has no memory effect.  It is recharged from where it remains.  It is 33-50 % more powerful then the Nicad.  It is economic not very expensive.  It has same size as Nicad and environmentally friendly. LiIon (Lithium Ion Battery)  LiIon is the best battery for laptop computers.  It has no chance for memory effect.  It is small then other batteries and also currently used in mobile phones.  It has more powerful then the other above-mentioned batteries.  It is so expensive then other batteries. (Portable system’s batteries should be disposed off properly according to local environmental authority’s law)

AC Adapter AC adapter is used in portable systems for basically two purposes. First conversion of Ac to Dc volts for the motherboard. Secondly it charges the battery for use. Adapter is either internal or external, if it is internal it increase the weight of computer. External Ac adapter is easy to carry and more convenient to use.

Portable display There are some older display types that were used in computers and some newly introduced have better display.  CRT (Cathode Ray Tube) It is the old display type that is not so efficient. These displays are heavy and cannot fit in portable systems so other generation for laptops introduced.  LCD (Liquid Crystal Display) LCD is more thin, low power consumed and lighter then the small CRT displays. It has two types of display…

ACTIVE MATRIX In active matrix there are one transistor is used for each pixel and produce the high quality image. This technology of active matrix is called TFT (Thin Film Transistor), which is currently used in computer’s displays.

PASSIVE MATRIX In passive matrix there are two rows of transistors only used for display.

When you see the picture from any other angle the quality of picture is lose.

(Any type of display should be clean with dump cloth)

Hard Drive All hard drives in portable systems have 2.5 inch EIDE or UDMA.

PCMCIA and PC Cards Personal Computer Memory Card International Association or Pc cards are the standard of portable system’s interfaces that is developed in 1989. First version of these cards that has 68 pins especially for memory is came in June 1990. There are three types of pc cards used in portable computers…

Cards and their descriptions… Type I II III

Thickness

Description

3.3 mm Memory 5.0 mm Cards IO devices 10.5 mm Mass storage device HDD All cards are 85.6 mm by 54.0 mm in size

Services In Portable Systems There are two basic services found in portable systems…

Socket Services Socket services in portable systems are responsible for BIOS level configuration. Insertion and removal of any card, memory or device. Card Services Card services are allows the system configurations for the incoming device and cards. They allow the system resources to the pcmcia cards. Pointing Devices There are many pointing devices are used in laptops…

Track Ball This is the most moving part of laptop. Pointing Stick It is a stick that is just like a pencil. Touch Pad Mostly used in latest laptops.

Printers Printer operations and components

Types of Printers Basically there are two major types of printers…

Impact Printers Impact printers are those printers in which the physical components are attached with the paper for printing. Daisy Wheel Printer Dot Matrix Printer

Non-Impact Printers In non-impact printers physically printer not attached with paper to draw the image. Ink Jet Printer Bubble Jet Printer Laser Printer

Daisy Wheel Printer      

Daisy wheel printer is the oldest form of impact printer. It had limited characters on it. It is work just like a typewriter. It is effective printer if you have any document in parts printing. It creates a lot of noise during printing. It had also ribbon for printing.

Dot Matrix Printer    

Dot matrix printer is the most efficient printer of impact class. It had print head that has pins in the range of 7,24 or 9,24. It is the hottest part of dot matrix printer. Dot matrix printer has the printing mechanism of firing the pins on the paper from the head. It had solenoid.

In Dot matrix printer there is the FRU is printer head.

According to A+ paper you must sure that there is only print head in a Dot matrix printer that you should never touch, because it is very hot and can burn your hand.

Laser Printers The printer that is associated with electricity to build the image on paper is called laser printer. There are some phases of laser printing that are much important for the exam. Phases of printing of Laser Printer “Charlie Chaplin Was Dancing On Third Floor” Cleaning-Charging-Writing-Developing-Transferring-Fusing

Cleaning This is the first step of laser printing in which the EP drum cleared with equipment that is called ‘cleaning blade’. Cleaning blade clears all charge from the drum and make it clean for new printing. Charging In this phase a wire that is called ‘primary corona wire’ charge the EP drum with –5000 volts. Writing In this process when the drum held the –5000 volts DC, the writing process makes the image on the drum with –100 DC volts. Developing In developing process the toner particles are transferred on the drum. So it is ready to transfer the image on paper. Transferring In this step ‘transfer corona wire’ works. It is situated on the back of paper and charge it with + volts so the –100 DC and + volts attract each other and the image is transferred on the paper. Fusing The last phase when the printing completes, the paper is smudged and should be dry. The fuser dries the paper with heat. Fuser heats up 165C to 180C. It consists of three main parts… Halogen heating lamp Rubberized pressure ruler Teflon-coated aluminum fusing roller Thermal fuser is used to manage the heat of fuser.

Trouble Shooting of Printers

Dot Matrix  If printer has left the line in words like “Certification” there should be one pin is not firing.  If the printer lose many words or line in printing there may be the cause of internal printer’s data cable.  If you found the printer is not printing straight, check the ruler.  Printer is printing garbage then checks the drivers.  If printing is too light then change the ink ribbon.

Laser  Blank pages can be the cause of…

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 If toner is end.  If transfer corona wire fails.  HVPS fails. Speckled pages can be the cause of; cleaning process is not properly works. Ghosted images can be the two causes…  Cleaning blade.  Lamp eraser not erases the previous image. Smudged images are only the cause of defective fuser. Paper is not goes in printer can be the cause of defective sensor.

Bubble Jets/Ink Jets  There is common problem in these printers that they finished the ink cartridge.  The platters and all circuits are built on the cartridge.  If cartridge’s circuit side is black with ink, clean it. Note “There is a common problem with all type of printers that they don’t have some time compatible driver so you should be sure that the driver you install is correct” Printer connections and configuration

Parallel Parallel cable’s recommended length is 10 feet. The connector that attached to the computer is DB-25 and at printer side is male Centronics-36. Serial The serial cable can be as far as 25 feet. Serial cable consists of DB-9 or DB-25 female connector on the computer and at printer side it is DB-25 male.

Network Some printers now days have LAN cards in them and allow you the serial and parallel interfaces in them to share them among all network. Normally they are software-based printers with a software Rom in them. Network cable is according to that cable limits that you are used.

Infrared It is basically the data transferring with light at a high speed. Currently mostly computers especially laptops supports it. It is infrared serial port.

Diagnosing And Troubleshooting Symptoms and problems

Processor/Memory There is a common problem with the clock speed of processor and Memory that they did not match and computer didn’t work. If you insert new Ram and display did not appear, check the Ram plugged properly or not. If processor continuously heat up without any physical reason, check its properties in CMOS setup and low its speed. Input Devices

Keyboard  Sticking keys/Sporadic keys: the keyboard should well clean then it works fine.  Non-functional keys: when any key stops functioning you should replace the keyboard.

Mouse  Dirty Mouse Mouse should be cleaned very well with the Q-tip, so it has no jerks.  Conflicting Address Some time address can be conflicting with any other IO device.  Device Driver If you have an operating system that has some problem and want the drivers, then you should provide the proper drivers for mouse.  Adapter Card If computer have the adapter card for mouse then check that too, normally old computers have IO card for this device.

Scanner  Device Driver You should provide the proper drivers for the device to make it work fine.  Adapter Card

If computer have the adapter card for scanner then check that too, normally scanners have the scanner card to plug.  Dirty Scan Dirty scan is happened when the surface of scanner have dust on it.  Cable and power connection issues

Floppy Disk Drive  Floppy Drive Failure; there may be the problem with FDD so you can check first disk then check the Drive.  FDD has no light ON; it can be the cause of power connection is not attached with it.  FDD’s light is ON continuously; the ribbon cable is attached with FDD reversed.  Media Error; if floppy is not formatted it display “invalid media error”  Drive incompatibility; sometime drive is not compatible when you copy some thing from any other computer.  Dirty read/Write head; check another floppy and then for drive.  Device driver errors; drivers are not compatible.  Drive fail; drive is not configured or out of order.

Hard Drive There are some common HDD problems…

Power connection Mostly power supply cable is not properly attach with HDD so it stops during work and system halts.

Cabling You have to configure properly master and slave jumpers on the hard disks so they work fine.

Address conflicts Some time controller’s address can be conflicted and hard disk drive fails.

BIOS setting There is properly setting of “first boot device and second” to work fine with hard disk drive. You should properly configure the LBA mode for hard disk drive.

Device drivers Sometime HDD needs drivers to run.

Corrupted drives This can be happened due to the bad sectors or clusters. You should choose any third party software or Scandisk of Microsoft to accomplish with it.

Non-system disk errors When there is no system files find on the hard disk drive.

Invalid media type error When hard disk drive is not formatted.

Fixed disk error There may be the problem of Rom Bios setting.

Current drive is no longer valid When the drive letter in autoexec.bat file is not correct.

No operating system found error There may be the cause of missing system files and secondly wrong CMOS setting.

Bad or missing operating system When no partition is active or Rom Bios setting.

CD-ROMs  Media errors due to bad drive.  Power problems are too common.  Disk is not read by Drive, try other disks first then Drive.

Parallel Ports/Serial Ports Serial and parallel ports are checked by the lope back test. That is performing with lope back adapter.

Sound Card/Audio There is normally the driver and the configuration problems are occurred in sound card. Monitor/Video  You should set the proper refresh rate of monitor as read in chapter.  If your computer goes directly in safe mode there is problem with the VGA driver.  If your system is starts flickering, set the sync frequency properly.

Modems     

No dial tone message, when phone line may be dead. Internet is disconnecting continuously, check the distortion in phone line. When you connect on Internet mouse works stop, check resources. When you install the external modem on COM 1 COM 3 cannot use. When you install the external modem on COM 2 COM 4 cannot use.

BIOS  Your computer did not support the HDD above 8 GB.  Your computer is not support the VGA monitor.  Motherboard has no support for booting from the CD-Rom.  Motherboard did not support the 1.44mb FDD.

Power Supply    

The computer is restarting continuously. When insert disk in CD-Rom the computer restarts. Computer is heat up but the processor fan is fine. Fan of power supply is out of order, then replace the power supply.

Slot Covers All computer covers should be at their place, if you had some problem of overheating of your computer keep the covers on the slots.

Device Drivers All devices those want the driver you should install the proper driver for them.

LBA (Logical Block Addressing) mode In BIOS the setting of hard disk drive should be the LBA if you had a large hard disk. Windows and Dos installs only on LBA mode.If your computer did not detect the complete hard disk drive. Set it at LBA mode.

POST Audio/Visual Error Cods

Error number or range 100-199 200-299 300-399 400-499 500-599 600-699 1700-1799 1780 1781 161 164 201 301 303 423 Continuous beep I beep No beep 5 short beep in AMI 4 short beep in AMI

Component or problem Mother Board Problems Memory Errors Keyboard Errors Video Problem (Monochrome) Video Problem (Color) Floppy Disk Drive Hard Disk Drives C drive of Hard disk D drive of Hard disk CMOS battery fails (change it) Memory size error (it occurs after memory upgrade run setup) Memory test fail (Ram chip fails during test) Keyboard did not response (want cleaning) Keyboard or system unit error (keyboard should be changed) Parallel test failure Hardware problem It is fine Speaker is out of order Processor failure System timer fails

6 short beep in AMI

Keyboard controller error

Basic troubleshooting First of all when any customer calls you, you should gather the information about the problem with his computer. Then check the environment of the place, then go for the problem’s actual location that whether it is a hardware or software problem.

Basic Networking Networking means the sharing of resources and it is same in computer networking that you can access one printer from another computer. It may possible that you can print your document from a remote printer through network redirector. Types of Networking There are basically three types of network but originally in real world only two types are used and found.  Local Area Network Local area network is the network type that is consists within one building or within one geographical area. All small networks like college lab and Internet café are the common examples of LAN. Physical Topologies under LAN • Bus • Star • Ring  Metropolitan Area Network In real world there is no implement of MAN, but it is the network within the city or where area code is same.  Wide Area Network Now a day’s world is based on web and Internet is the most efficient example of WAN. Physical Layout of Local Area Network

There are three main physical topologies of network. Bus Topology  Bus topology is such network layout that all computers used the same media and attached with that.  The worst condition is in bus topology is that, if the network cable breaks from anywhere all network goes down.  The trouble shooting of this network is quite difficult as compare to star.  Coaxial cable is used in this Topology.

Star Topology  This type of network has the centralized management that is implemented with a device called HUB.  All computers in star topology are directly connected to that hub.  Trouble shooting of star is quite easy.  Every computer has its own connection to the hub if any computer’s cable breaks or down the LED’s can easily helps you to determine which computer has problem.  Twisted Pair cable is used in this network Topology.

Ring Topology  Ring topology has no implement in real world but required in course. In ring topology all computers are connected as the bus.  It is also called the MAU (Multi Station Access Unit).  There is no chance of collision in this topology due to the ‘Token passing’.  Fiber Optic cable is used in this Topology.  The default method of network access is Token Passing, if the network is about 1  It is same as bus topology that if the cable is breaking from anywhere all networks goes down. IEEE Standard LLC Ethernet Token Ring LAN Token Bus LAN MAN

802.2 802.3 802.5 802.4 802.6

Logical Networking Logical types of networking is the way that how computers access the network. Peer To Peer  In such network all computers have the equal access to the network.  All computers have the equal rights and share the resources equally.  Microsoft Windows 95,98,Me support this type of network. Client Server  In client server architecture one computer have all the rights of any network and allows the other computers to access the resources in a predefined limit.  Server has the right to restrict any user to access the networks resources.  Client have proper authentication from the server and then enter in the network. Client Server Operating Systems Microsoft windows NT workstation and Server Microsoft windows 2000 professional and Advance Server Red Hat Linux Unix Sun Solaris

Basic networking concepts

Cabling RG58 with 50ohm impedance for Thinnet. RG59 with 75ohm impedance for TV. RG8 and 11 for Thicknet cable. Coaxial cable has two different types that are used in networking.

Thinnet Cable  Thinnet cable is commonly used it the Bus Topology.  Its connectors are as follows… o BNC (British Naval Connector) o T-Connector o ETR (End Terminator (50 ohm))  Thinnet cable can take the data up to 185 or 180 meter (610 feet).  After that limit a device is used called “Repeater” to regenerate the signals.  This cable has more EMI effect as compare to Thicknet.  It supports 30 nodes on one segment.

Thicknet Cable     

Thicknet cable is used where EMI chances are great. It is more thick then the Thinnet and attached with a transceiver. The connector in this cable is used called ‘N’ connector. Thicknet cable can take the data up to 500 meter (1650 feet). It supports 100 nodes on one segment.

Twisted Pair Cable Twisted pair cable has two types… UTP (Unshielded Twisted Pair) STP (Shielded Twisted Pair) UTP

Shielded Twisted Pair Cat1Cat2 4Mb/sec Cat3 16 Mb/sec Cat4 100\20Mb/sec Cat5 100 Mb/sec Cat6 155Mb/sec Cat7 1000Mb/sec

voice telephone network Ethernet and Fast Ethernet Fast Ethernet Gigabit Ethernet

(Connector for UTP and STP cable is “RJ45”)

UTP Unshielded Twisted Pair  It supports the 75 nodes on a channel.  It has not efficient against the EMI.  It has the limit of 100 meters or 328 feet.  Data transferring speed is 100mb/s STP    

Shielded Twisted Pair It supports the 200 nodes on a channel. It has more efficient against the EMI. It has the limit of 100 meters. Data transferring speed is 100mb/s

Ethernet Standards Cable Thinnet Thicknet Twisted pair

Standard 10base2 10base5 10baseT

Attenuation Weakness of network signals after a specific limit is called Attenuation. Cross Talk When the signals of one cable attract with other is called cross talk. It is happened due to combined path of cables. Noise Noise is another term of cross talk but it is happened due to the heavy machinery like UPS and other. UPS provides the noise filter in it so it has no effect of our cables. FIBER FOPTIC It is the fastest media of transmission. Its data transmitting speed is2gb\sec. This cable has two types of manufacturing. It is the media that is transferred data in shape of light.

 Tight configuration  Loose configuration  Single Mode Optic Fiber Injection laser diodes ILD’s are commonly used in the single mode.

 Multi Mode Optic Fiber Light-emitting diodes LED are to transmit the data.

Network Interface Cards NIC card is the expansion card that is used for networking. Its basic working is to transmit the data out from computer and receive the incoming messages. It is the I/O device. NIC card is Network Access In a network when all or some computers sends the data at the same time, that data can cause the jam on the network or mess up and block the media is called collision. To avoid or protect the network from collision there are network access method are used as follows…  CSMA\CD (Carrier Sense Multiple Access\Collision Detection) This network access method is used in Ethernet networks. In this method all NIC cards sense the network media that is there any data transferring is going on or not. If the media is found free then NIC card transmit the data on the cable otherwise wait for free path.  CSMA\CA (Carrier Sense Multiple Access\Collision Avoidance) This is the way if any collision is occurred on network then how to make it normal. In this method all computers stops the data transferring on media and remaining data that is being mess up in media, back to their originators. There is ‘BACK OFF’ algorithm is used in this method.  Token Passing This is network access method of Token Ring network. In this method there is no chance of collision because of a software packet that is called token is passed through all nodes of network. When any nodes pick this packet then he transmits the data. If the network is 200 meter then token is to be passed 10000 times to every computer. Protocols There are basic two protocols used in the networking… Routable There is the protocol that is used on the Internetworks called routable protocol. TCP/IP (Transmission Control Protocol/Internet Protocol) TCP/IP suit is the most common protocol that is used in Internet. You cannot connect or used the Internet without it. TCP/IP is based on ip addressing. It is called 32 bit addressing and used the classes… 0-255 Class A 1-126 Class B 128-191 Class C 192-223 It is also supports the sub-netting of any network… Class A 255.0.0.0 Class B 255.255.0.0 Class C 255.255.255.0 IPX/SPX (Internetwork Packet Exchange/Sequenced Packet Exchange) IPX/SPX is the routable protocol of Netware. It is not used in Internet only used in Novell’s systems.

No-Routable There is the common Microsoft’s protocol that is used commonly on LAN.

NETBEUI NetBEUI is the small network’s protocol that is commonly used by the Microsoft. It is very easier to configure and is working on the computer name or Net Bios name.

Broadband & Baseband To understand broadband and baseband, one needs to know two basic terms first: TDM and FDM.

 TDM stands for Time Division Multiplexing. You can think of TDM as Time Division plus Multiplexing. Multiplexing means that you can transmit multiple signals simultaneously over a single transmission path. Time Division means that you slice the time in order to transmit different signals. TDM technology is used in T carries such as T1, T2, which is very popular in WAN environment.

 FDM means Frequency Division Multiplexing. Same as TDM, FDM also transmits signals simultaneously over a single transmission path, such as a cable or wireless system. However, TDM slice the time while FDM separate signals by its own unique frequency range. Typical example of FDM is cable TV system. Although you only have one cable (means one channel), you can receive several TV channels. Each channel has a different frequency range. That is the reason why when you switch to channel 3, you go to NBC, and to channel 5 you go to CNN…

 Baseband A communications technique in which digital signals are placed onto the transmission line without change in modulation. If you study TDM and FDM carefully, you will find TDM doesn't need modulation because it just put the signal into a specific time interval. While FDM needs modulation because it put all the signals together for the transmission. Therefore, Baseband is using the TDM technology.

 Broadband A technique for transmitting data, voice and video using FDM. Modems are required for this method, because the digital data has to be modulated onto the line. The typical example of broadband is cable TV as well as radio station. 1. Baseband refers to single frequency while broadband refers to multiple frequency ranges. 2. Baseband is bi-directional while broadband is unidirectional. 3. Baseband uses repeater to regenerate the signal while Broadband uses amplifier to regenerate signals. Configuring network interface cards Configuration of network interfacing card is so simple now a days due to pnp. They held an IRQ and IO address. Mostly in Windows NT the problem is occurred because LAN card and sound card accept the same IRQ, that is 5. Problems on the network There are some common problems are faced in a network.  Wrong Driver

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Physical cable damaged LAN card is damaged Hub is not plugged properly EMI effect due to magnetic field High voltage machines near the cables Excessive traffic and low bandwidth

Reduce Bandwidth Reduce Bandwidth occurs when user’s data transmission across the network being to take longer. The time out of application for requesting of transmission is occurred. It is commonly occur when network traffic is acceding. The most efficient solution for this problem is to increase the network components. Increase the bandwidth 10mb\sec to 100mb\sec by replacing the hubs, NIC and cables.

Loss of Data Network’s main issues are Data safety and security. Loss of data can be occurring due to some transmission problems, some transmission methods provide the assurance for successfully data transmission across the nodes. It is not cause of excessive traffic on network but can be occur due to failure of some hardware.

Network Slowdown Mostly when administrator takes the backup of network data the network slow down. Another cause of slow network is low bandwidth, that if your network is so big and the data transfer rate among nodes is high then you should increase the bandwidth for avoid the slowdown of network. DUPLEXING Simplex It is just one-sided transmission Half Duplex Half duplex is the transmission of one sided just like when you send the data, other person cannot. Full Duplex It is just like your normal phone lines. It is two-way communication that allows the both sides to transmit the data at the same time. EXPANDING NETWORK’S DEVICES Hubs It is used in star network for the centralized management. It has two main types.. Active Hub Passive Hub Switches It is just like hub but so intelligent and used to combine more then 100 networks individually. That is mostly used in ISPs. Repeater

It is the device that is used to regenerate the network signals after the end limit of any cable. Router It combines the different networks and used to expand the network through the World Wide Web commonly. It is mostly used in ISPs. Router creates the routing table that is so efficient way to control the network traffic. Modem It is used to dial the Internet. It has two main forms… Internal modem External modem Bridge Bridge can combine the two networks using the ip addresses. Brouter Router + Bridge = Brouter Gateway Gateway is basically used to convert the protocols. Its working is to combine the different networks.