Hardware Book 1

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Preface

Nowadays Hardware and networking career is becoming more

sought after and the demand for the course is increasing.

Expertise in the Hardware field developed over the last two

decades feels proud in dedicating this book for the benefit of

the students undergoing Hardware training. Wishes to thanksfor read this book.

- MR.M. NAVEEN KUMAR

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SYLLABUS

Unit 1

Basic of electronic introduction of computer types of computer computer generations processor introduction.

Unit 2

Introduction to mother board introduction to ATX processor &sockets introduction to bios Disk operation system Introductionto floppy Hard disk CD & DVD.

Unit 3

Peripherals Pci slots External cards RAM Motherboar block diagram - SMPS.

Unit 4

Troubleshooting OS installation Software installation servicingtechnique (theory only) assembling.

Unit 5

Introduction to Networking Types of networking Topologies Scripts Sharing Remote connections.

Unit 6

Computer viruses types of virus Computer maintenance.

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Unit 1

BASIC OF ELECTRONIC :

Electronic components are Resistors, Capacitor, Diode, PCB board, Transistors, ICs andsockets.Resistors : A resistors is a two-terminal electronic component that produce a voltage acrossits terminals that is proportional to the electric current passing through it in accordance withohms law V=IR. Refer fig. 1 Resistor diagram

Fig 1 Resistor

Capacitor: A capacitor is a passive electronic components consisting of a pair of conductorsseparated by a dielectric. The capacitors charge a temporary current using circuit. Refer fig1.1

Refer fig 1.1

Diode:In electronics, a diode is a two terminal components that conduct electric current inonly direction. The term usually refers to a semi conductor diode, the most common type

today. A vacuum tube diode with two electrodes a plate and a cathode. Fig shown in 1.2

Fig shown in 1.2

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Transistor: A transistor is a semiconductor device used to amplify and switch electronicsignals. It is made of solid piece of semiconductor material, which at least three terminals forconnection to external circuit. A Voltage or current applied to one pair of the transistorsterminals change the current flowing through another pair of terminals. Because thecontrolled power can be much more than the controlling i/p power, the transistor provides of

amplification a signal. Some transistors are packaged individually but many more are foundembedded in integrated circuits. Refer fig 1.3

Fig 1.3

Introduction to computer

A computer is a machine that manipulates data according to a list of instructions. A computercan also be defined as an electronic machine that concepts input data, processes in and givesout results. A basic computer consists of three major components: cpu (central processingunit), IO (input and output), and Memory as illustrated.

Fig. 1.4

Computers were initially large machines that could fill entire room. Some were operatedusing large vacuum tubes that formed the basis of todays transistors. In order to operatorsuch machine, punch card were used.1833 Charles Babbage invented his difference engine anearly calculator. Together with the punch card design, he created the analytical engine.Regrettably the engine never saw completion due to political issues.Here are some computers that came and went in the history of computing. Some modernexamples are also here.ENIAC: ENIAC stood for Electrical Numerical Integrator and Computer. The ENIAC used

thousands of vacuum tubes and a punch card mechanism.

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Fig 1.5

Commodore 64: An 8 bit computer introduced in January 1982, the commodore rose tobecome the best selling personal computer of all times. Utilising the commodore BASIC programming language licensed from Microsoft, the commodore was able to host over10,000 commercial programs.

Macintosh: First introduced by apple 1984, the Macintosh was the first computer to use amouse and graphical user interface (gui) rather than a command line interface. Until thedominance of the IBM Pc, the Macintosh saw use primarily as a desktop publishing tool.

Types of computer

1. Super computer2. Main frame3. Work station4. The personal computer or PC5. Micro controller6. Server

Supercomputer:

Super computer are fast because they are really many computers working together. Supercomputer were introduced in the 1960s as the worlds most advanced computer. As of

November 2008, the fastest super computer is the IBM roadrunner. It has theoreticalprocessing peak of 1.71 petaflops and has currently peaked at 1.456 petaflops.

Mainframe: They are computer where all the processing is done centrally and the userterminals are called dumb terminals since they only input and outputs.Mainframes are computers used mainly by large organizations for critical applications,typically bulk data processing such as census. Examples: banks, airlines, insurancescompanies, and colleges.

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Workstation: Workstation are high-end expensive computer that are made for complexproducers and are intended for one user at a time. Some of the complex producers consist ofscience, math and engineering calculations and are useful for computer design andmanufacturing. Workstations are some times improperly named for marketing reasons. Real

workstations are not usually sold in retail.

Personal computer: Pc is an abbreviation for a personal computer, it is also known as amicrocomputer. Its physically characteristics and low cost are appealing and useful for itsusers. By the early 1970s people in academic or research institutions had the opportunity forsingle-person use of a computer system in interactive mode for extended durations.

Microcontroller: They are mini computers that enable the user to store data, do simplecommands and tasks, with title or no user interaction with the processor. These single circuitdevices have minimal memory and program length but can be integrated with other processorfor more complex functionality.

Generation of computers

Computer Has Five generation of computers. They are below.First generation (vacuum tubes)Introduce in 1940-956.Second generation (Transistors)Introduce 1947-1950sThird generation (integrated circuits (IC))Introduce in 1964-1971

Fourth generation (microprocessors)Introduce in 1971 presentFifth generation (present and beyond ) Artificial intelligence

Processor Introduction

If example Pentium IV processor contains a million type of transistor in that processor &designed. First generation processor contain using 80XXX series, Second generation802XXX series used, second generation processors using a expansion slots type processors.

Refer slide

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UNIT 2

INTRODUCTION TO MOTHER BOARD

A mother board made up ofPCB board. If mother board have double circuits Front ofcomponent and back side Circuits can link. Mother board consists of

1. BIOS & CMOS BATTERY2. CHIPSET3. PCI SLOTS4. EXPANSION SLOTS5. BRIDGES6. PROCESSOR SLOTS

7. POWER CONNECTOR8. IDE9. HARD DISK (HDD)10. DVD & CD (DVD)

Also referred to system board and main board. The motherboard is the foundation of thepc system. Without the motherboard there would be no computer. Now there are some majorparts of the motherboard that you need to understand and get very familiar. As always I willtry to make this is as simply to understand as possible.

So you know what the main idea is of the motherboard now you need to know what its

functions are and how it works. Take a look at functions.

MOTHER FUNCTIONS

The mother takes care of the entire system task in one way or another. It is a go-betweenof the system. You will find that almost all component are attached to motherboard in oneway or another way. Without the motherboard these system components would be hard

pressed to work.

Dont go cheap on this item and get a good one. When deciding on a case and processorswe need to be concerned with designs.

Motherboard formats

When it comes to format we all need to pay attention not only to motherboard format butalso case format. The formats used today are mainly the ATX, and the AT. These are the onlystyles you should worry about until things change again and there is a better alternative.

AT- this is a design that is fathered after IBM and very common. Though the style is oldand not really recommended today. There are many motherboard manufacturers that stillmake AT boards for those trying to save a buck.

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Baby AT- The baby AT is a smaller than the AT and is found in many cloned IBMmachines today. Like the AT it is an old style and is slowly fading out to the ATX.

ATX- this is becoming the standard and a nice motherboard. The board is modeled after the

baby AT design except the board is turned 90 degrees in the case allowing much room for bigexpansion cards.

-For those of you that go ahead and throw in a few more dollars and get a ATX motherboardand the case you will be very pleased. The transition is an easy one from the old school styleof the AT format to the new ATX.

-So what it the Core parts of the motherboard and what do they do for you? Check out someof the components and learn more.

INTRODUCTION TO ATX

ATX (Advanced Technology Extended) is a computer form factor specification developedby Intel in 1995 to improve on previous de facto standards like the AT form factor. It was the

first big change in computer case, motherboard, and power supply design in many years,improving standardization and interchangeability of parts. The specification defines the keymechanical dimensions, mounting point, I/O panel, power and connector interfaces between acomputer case, a motherboard, and a power supply. With the improvements it offered,including lower costs, ATX overtook AT completely as the default form factor for newsystems within a few years. ATX addressed many of the AT form factor's annoyances thathad frustrated system builders.

Other standards for smaller boards (including microATX, FlexATX and mini-ITX)usually keep the basic rear layout but reduce the size of the board and the number ofexpansion slot positions. In 2003, Intel announced the BTX standard, intended as areplacement for ATX. As of 2009[update], the ATX form factor remains a standard for do-it-

yourselfers; BTX has however made inroads into pre-made systems.

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PROCESSOR & SOCKETS

1. CPU (central processing unit) an electronic circuit that can execute computer programs2. Microprocessor, a CPU on one chip as part of a microcomputer

3. Graphics processing unit (GPU / VPU), a dedicated graphics rendering device for apersonal computer or game console4. Physics processing unit (PPU), a dedicated microprocessor designed to handle thecalculations of physics5. Digital signal processor, a specialized microprocessor designed specifically for digitalsignal processing6. Network processor, a microprocessor specifically targeted at the networking applicationdomain7. Front end processor, a helper processor for communication between a host computer andother devices8. Coprocessor9. Floating point unit10. Data processor, a system that translates or converts between different data formats11. Word processor, a computer application used for the production of printable material12. Audio processor, used in studios and radio stations

8080Introduced April 1, 1974Clock rate 2 MHz0.64 MIPSBus Width 8 bits data, 16 bits address

Enhancement load NMOS logicNumber of Transistors 6,000Assembly language downwards compatible with 8008.Addressable memory 64 KBUp to 10X the performance of the 8008Used in the Altair 8800, Traffic light controller, cruise missileRequired six support chips versus 20 for the 8008

8085Introduced March 1976Clock rate 3 MHz0.37 MIPSBus Width 8 bits data, 16 bits addressDepletion load NMOS logic

Number of Transistors 6,500 at 3 mBinary compatible downwards with the 8080.Used in Toledo scales. Also was used as a computer peripheral controller modems,harddisks,printers, etc...CMOS 80C85 in Mars Sojourner, Radio Shack Model 100 portable.High level of integration, operating for the first time on a single 5 volt power supply, from 12volts previously. Also featured serial I/O,3 maskable interrupts,1 Non-maskable interrupt,1

externally expandable interrupt w/[8259],status,DMA

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Pentium (chronological entry)

Introduced March 22, 1993See main entry

[edit] 80486DX4Introduced March 7, 1994Clock rates:75 MHz with 53 MIPS (41.3 SPECint92, 20.1 SPECfp92 on Micronics M4P 256 KB L2)100 MHz with 70.7 MIPS (54.59 SPECint92, 26.91 SPECfp92 on Micronics M4P 256 KBL2)

Number of Transistors 1.6 million at 0.6 mBus width 32 bitsAddressable memory 4 GBVirtual memory 64 TBPin count 168 PGA Package, 208 sq ftP PackageUsed in high performance entry-level desktops and value notebooksFamily 4 model 8

32-bit processors: P5 microarchitecture

Original Pentium

Bus width 64 bitsSystem bus clock rate 60 or 66 MHzAddress bus 32 bits

Addressable Memory 4 GBVirtual Memory 64 TBSuperscalar architectureRuns on 5 voltsUsed in desktops16 KB of L1 cacheP5 0.8 m process technologyIntroduced March 22, 1993

Number of transistors 3.1 millionSocket 4 273 pin PGA processor packagePackage dimensions 2.16" x 2.16"Family 5 model 1Variants60 MHz with 100 MIPS (70.4 SPECint92, 55.1 SPECfp92 on Xpress 256 KB L2)66 MHz with 112 MIPS (77.9 SPECint92, 63.6 SPECfp92 on Xpress 256 KB L2)P54 0.6 m process technologySocket 5 296/320 pin PGA package

Number of transistors 3.2 millionVariants75 MHz Introduced October 10, 199490, 100 MHz Introduced March 7, 1994

P54CQS 0.35 m process technologySocket 5 296/320 pin PGA package

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Number of transistors 3.2 millionVariants120 MHz Introduced March 27, 1995P54CS 0.35 m process technology

Number of transistors 3.3 million

90 mm die sizeFamily 5 model 2VariantsSocket 5 296/320 pin PGA package133 MHz Introduced June 12, 1995150, 166 MHz Introduced January 4, 1996Socket 7 296/321 pin PGA package200 MHz Introduced June 10, 1996[edit] Pentium with MMX TechnologyP55C 0.35 m process technologyIntroduced January 8, 1997

Intel MMX (instruction set)

Socket 7 296/321 pin PGA (pin grid array) package32 KB L1 cache

Number of transistors 4.5 millionSystem bus clock rate 66 MHzBasic P55C is family 5 model 4, mobile are family 5 model 7 and 8Variants166, 200 MHz Introduced January 8, 1997

233 MHz Introduced June 2, 1997133 MHz (Mobile)166, 266 MHz (Mobile) Introduced January 12, 1998200, 233 MHz (Mobile) Introduced September 8, 1997300 MHz (Mobile) Introduced January 7, 1999

32-bit processors: P6/Pentium M microarchitecture

Pentium Pro

Introduced November 1, 1995Precursor to Pentium II and IIIPrimarily used in server systemsSocket 8 processor package (387 pins) (Dual SPGA)

Number of transistors 5.5 millionFamily 6 model 10.6 m process technology16 KB L1 cache256 KB integrated L2 cache60 MHz system bus clock rateVariants

150 MHz

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0.35 m process technology, or 0.35 m CPU with 0.6 m L2 cacheNumber of transistors 5.5 million512 KB or 256 KB integrated L2 cache60 or 66 MHz system bus clock rateVariants

166 MHz (66 MHz bus clock rate, 512 KB 0.35 m cache) Introduced November 1, 1995180 MHz (60 MHz bus clock rate, 256 KB 0.6 m cache) Introduced November 1, 1995200 MHz (66 MHz bus clock rate, 256 KB 0.6 m cache) Introduced November 1, 1995200 MHz (66 MHz bus clock rate, 512 KB 0.35 m cache) Introduced November 1, 1995200 MHz (66 MHz bus clock rate, 1 MB 0.35 m cache) Introduced August 18, 1997

Pentium II

Introduced May 7, 1997Pentium Pro with MMX and improved 16-bit performance242-pin Slot 1 (SEC) processor packageSlot 1

Number of transistors 7.5 million32 KB L1 cache512 KB bandwidth external L2 cacheThe only Pentium II that did not have the L2 cache at bandwidth of the core was thePentium II 450 PE.Klamath 0.35 m process technology (233, 266, 300 MHz)66 MHz system bus clock rateFamily 6 model 3Variants

233, 266, 300 MHz Introduced May 7, 1997Deschutes 0.25 m process technology (333, 350, 400, 450 MHz)Introduced January 26, 199866 MHz system bus clock rate (333 MHz variant), 100 MHz system bus clock rate for allmodels afterFamily 6 model 5Variants333 MHz Introduced January 26, 1998350, 400 MHz Introduced April 15, 1998450 MHz Introduced August 24, 1998233, 266 MHz (Mobile) Introduced April 2, 1998

333 MHz Pentium II Overdrive processor for Socket 8 Introduced August 10, 1998;Engineering Sample Photo300 MHz (Mobile) Introduced September 9, 1998333 MHz (Mobile)

Celeron (Pentium II-based)

Covington 0.25 m process technologyIntroduced April 15, 1998242-pin Slot 1 SEPP (Single Edge Processor Package)

Number of transistors 7.5 millionSlot 1

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32 KB L1 cacheNo L2 cacheVariants266 MHz Introduced April 15, 1998300 MHz Introduced June 9, 1998

Mendocino 0.25 m process technologyIntroduced August 24, 1998242-pin Slot 1 SEPP (Single Edge Processor Package), Socket 370 PPGA package

Number of transistors 19 million66 MHz system bus clock rateSlot 1, Socket 37032 KB L1 cache128 KB integrated cacheFamily 6 model 6Variants300, 333 MHz Introduced August 24, 1998366, 400 MHz Introduced January 4, 1999433 MHz Introduced March 22, 1999466 MHz500 MHz Introduced August 2, 1999533 MHz Introduced January 4, 2000266 MHz (Mobile)300 MHz (Mobile)333 MHz (Mobile) Introduced April 5, 1999366 MHz (Mobile)400 MHz (Mobile)

433 MHz (Mobile)450 MHz (Mobile) Introduced February 14, 2000466 MHz (Mobile)500 MHz (Mobile) Introduced February 14, 2000

Pentium II Xeon (chronological entry)

Introduced June 29, 1998See main entry[edit] Pentium IIIKatmai 0.25 m process technology

Introduced February 26, 1999Improved PII, i.e. P6-based core, now including Streaming SIMD Extensions (SSE)

Number of transistors 9.5 million512 KB bandwidth L2 External cache242-pin Slot 1 SECC2 (Single Edge Contact cartridge 2) processor packageSystem Bus clock rate 100 MHz, 133 MHz (B-models)Slot 1Family 6 model 7Variants550 MHz Introduced May 17, 1999600 MHz Introduced August 2, 1999

533, 600 MHz Introduced (133 MHz bus clock rate) September 27, 1999Coppermine 0.18 m process technology

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Introduced October 25, 1999Number of transistors 28.1 million256 KB Advanced Transfer L2 Cache (Integrated)242-pin Slot-1 SECC2 (Single Edge Contact cartridge 2) processor package, 370-pin FC-PGA (Flip-chip pin grid array) package

System Bus clock rate 100 MHz (E-models), 133 MHz (EB models)Slot 1, Socket 370Family 6 model 8Variants500 MHz (100 MHz bus clock rate)533 MHz550 MHz (100 MHz bus clock rate)600 MHz600 MHz (100 MHz bus clock rate)650 MHz (100 MHz bus clock rate) Introduced October 25, 1999667 MHz Introduced October 25, 1999700 MHz (100 MHz bus clock rate) Introduced October 25, 1999733 MHz Introduced October 25, 1999750, 800 MHz (100 MHz bus clock rate) Introduced December 20, 1999850 MHz (100 MHz bus clock rate) Introduced March 20, 2000866 MHz Introduced March 20, 2000933 MHz Introduced May 24, 20001000 MHz Introduced March 8, 2000 (Not widely available at time of release)1100 MHz1133 MHz (first version recalled, later re-released)400, 450, 500 MHz (Mobile) Introduced October 25, 1999

600, 650 MHz (Mobile) Introduced January 18, 2000700 MHz (Mobile) Introduced April 24, 2000750 MHz (Mobile) Introduced June 19, 2000800, 850 MHz (Mobile) Introduced September 25, 2000900, 1000 MHz (Mobile) Introduced March 19, 2001

Intel Core

Yonah 0.065 m (65 nm) process technologyIntroduced January 2006533/667 MHz front side bus

2 MB (Shared on Duo) L2 cacheSSE3 SIMD instructions31W TDP (T versions)Family 6, Model 14Intel Core Duo T2700 2.33 GHzIntel Core Duo T2600 2.16 GHzIntel Core Duo T2500 2 GHzIntel Core Duo T2450 2 GHzIntel Core Duo T2400 1.83 GHzIntel Core Duo T2300 1.66 GHzIntel Core Duo T2050 1.6 GHz

Intel Core Duo T2300e 1.66 GHzIntel Core Duo T2080 1.73 GHz

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Intel Core Duo L2500 1.83 GHz (Low voltage, 15W TDP)Intel Core Duo L2400 1.66 GHz (Low voltage, 15W TDP)Intel Core Duo L2300 1.5 GHz (Low voltage, 15W TDP)Intel Core Duo U2500 1.2 GHz (Ultra low voltage, 9W TDP)Intel Core Solo T1350 1.86 GHz (533 FSB)

Intel Core Solo T1300 1.66 GHzIntel Core Solo T1200 1.5 GHz [35]

Dual-Core Xeon LV

Sossaman 0.065 m (65 nm) process technologyIntroduced March 2006Based on Yonah core, with SSE3 SIMD instructions667 MHz frontside bus2 MB Shared L2 cacheVariants2.0 GHz

32-bit processors: NetBurst microarchitecture

Pentium 4

0.18 m process technology (1.40 and 1.50 GHz)Introduced November 20, 2000L2 cache was 256 KB Advanced Transfer Cache (Integrated)Processor Package Style was PGA423, PGA478

System Bus clock rate 400 MHzSSE2 SIMD Extensions

Number of Transistors 42 millionUsed in desktops and entry-level workstations0.18 m process technology (1.7 GHz)Introduced April 23, 2001See the 1.4 and 1.5 chips for details0.18 m process technology (1.6 and 1.8 GHz)Introduced July 2, 2001See 1.4 and 1.5 chips for detailsCore Voltage is 1.15 volts in Maximum Performance Mode; 1.05 volts in Battery OptimizedModePower


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0.13 m process technology Northwood A (1.7, 1.8, 1.9, 2, 2.2, 2.4, 2.5, 2.6,2.8(OEM),3.0(OEM) GHz)Improved branch prediction and other microcodes tweaks512 KB integrated L2 cache

Number of transistors 55 million

400 MHz system bus.Family 15 model 20.13 m process technology Northwood B (2.26, 2.4, 2.53, 2.66, 2.8, 3.06 GHz)533 MHz system bus. (3.06 includes Intel's hyper threading technology).0.13 m process technology Northwood C (2.4, 2.6, 2.8, 3.0, 3.2, 3.4 GHz)800 MHz system bus (all versions include Hyper Threading)6500 to 10000 MIPS

Pentium Extreme Edition

Dual-core microprocessorEnabled Hyper-Threading800(4x200) MHz front side busSmithfield 90 nm process technology (3.2 GHz)VariantsPentium 840 EE 3.20 GHz (2 x 1 MB L2)Presler 65 nm process technology (3.46, 3.73)2 MB x 2 (non-shared, 4 MB total) L2 cacheVariantsPentium 955 EE 3.46 GHz, 1066 MHz front side busPentium 965 EE 3.73 GHz, 1066 MHz front side bus

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INTRODUCTION TO BIOS

BIOSThe Basic Input-Output System (BIOS) is an essential set of routines in a PC, which is

stored on a chip on the motherboard. It acts as an intermediary between a computer'shardware and its operating system. Without the BIOS, the PC's operating system would haveno way to communicate with, or take control of, the hardware.

In other words, the BIOS is a crucial component of any computer. If its options are setincorrectly, the BIOS could slow your computer down by as much as 40%. Unfortunately, asnew processors and motherboard chipsets are released, BIOS options continue to get evenmore confusing. As a result, many seasoned technicians are still baffled by the jargon-lacedand confusing options available in a modern computer's BIOS setup program.

Many large PC manufacturers such as Dell, HP, Gateway and Micron limit the optionsavailable to the end-user in the BIOS, in order to reduce ill-advised "tinkering" and theresulting support calls. As a result, you may not be able to take advantage of some of theadvanced settings mentioned here on PCs from these major vendors.

It is recommended that you reboot after each individual BIOS setting change to ensurethat your system functions normally. If you make numerous changes before rebooting, andyour system will no longer boot, you won't know which change is responsible for the failure.

DISK OPERATING SYSTEM

When the computer starts, it starts the operating system that takes the control of themachine. An Operating System is a set of programs that help in controlling and managing theHardware and the Software resources of a computer system. A good operating system shouldhave the following features:

1. Help in the loading of programs and data from external sources into the internal memorybefore they are executed.

2. Help programs to perform input/output operations, such as;

1. Print or display the result of a program on the printer or the screen.2. Store the output data or programs written on the computer in storage device.3. Communicate the message from the system to the user through the VDU.4. Accept input from the user through the keyboard or mouse

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As the name suggests, the operating System is used for operating the system or thecomputer. It is a set of computer programs and also known as DOS (Disk Operating System).The main functions of DOS are to manage disk files, allocate system resources according tothe requirement. DOS provides features essential to control hardware devices such asKeyboard, Screen, Disk Devices, Printers, Modems and programs.

Basically, DOS is the medium through which the user and external devices attached to thesystem communicate with the system. DOS translate the command issued by the user in theformat that is understandable by the computer and instruct computer to work accordingly. Italso translates the result and any error message in the format for the user to understand.

LOADING DOS

The BOOT Record into the computer memory loads DOS. BOOT Record in turn istriggered by ROM program already there in the computer.

The system start-up routine of ROM runs a reliability test called Power On Self Test (POST)which initializes the chips and the standard equipment attached to the PC, and checkwhether peripherals connected to the computer are working or not. Then it tests the RAMmemory. Once this process is over, the ROM bootstrap loader attempts to read the Bootrecord and if successful, passes the control on to it. The instructions/programs in the bootrecord then load the rest of the program. After the ROM boot strap loader turns thecontrol over to boot record, the boot tries to load the DOS into the memory by reading thetwo hidden files IBMBIO.COM and IBMDOS.COM. If these two are found, they areloaded along with the DOS command interpreter COMMAND.COM. COMMAND.COMcontains routines that interpret what is typed in through the keyboard in the DOS command

mode. By comparing the input with the list of command, it acts by executing the requiredroutines/commands or by searching for the required routine utility and loads it into thememory.

BOOTING

BOOT = Build Own Operate Transfer

In computing, booting (also known as "booting up") is a bootstrapping process that startsoperating systems when the user turns on a computer system. A boot sequence is the initialset of operations that the computer performs when power is switched on.

A computer's central processor can only execute program code found in Read-OnlyMemory (ROM), Random Access Memory (RAM) or an operator's console. Modernoperating systems and application program code and data are stored on nonvolatile datastorage devices, such as hard disk drives, CD, DVD, flash memory cards (like an SD card),USB flash drive, and floppy disk. When a computer is first powered on, it does not have anoperating system in ROM or RAM. The computer must initially execute a small programstored in ROM along with the bare minimum of data needed to access the nonvolatile devicesfrom which the operating system programs and data are loaded into RAM.

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The small program that starts this sequence of loading into RAM, is known as a bootstraploader, bootstrap or boot loader. This small boot loader program's only job is to load otherdata and programs which are then executed from RAM. Often, multiple-stage boot loadersare used, during which several programs of increasing complexity sequentially load one afterthe other in a process of chain loading.

BOOT LOADERS

BIOSOpenBIOSEFIOpenBootSLOF

Second-stage boot loader

The small program is most often not itself an operating system, but only a second-stageboot loader, such as GRUB, BOOTMGR, Syslinux, LILO or NTLDR. It will then be able toload the operating system properly, and finally transfer execution to it. The operating systemwill initialize itself, and may load device drivers that are needed for the normal operation ofthe OS. After that it starts loading normal system programs.

Some DOS commands:

CD To Go Inner DirectoryCD.. To go outer directoryDIR List the directoryRD To remove directoryCOPY copy any file in commandsMOVE move any file in commandsDIR/AH diplay hidden filesDIR/AS display system filesDIR/AR display read-only fileDEL delete filesRENAME (REN) rename filesFORMAT format drivesATTRIB To change file permissionCLS to clear screenDATE to display dateTIME To display timeEXIT exit from dosLABLE to display volume lableMKDIR to make new folder or directoryMD PROMPT $$ linuxVER To display msdos versionXCOPY copy entire directory

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INTRODUCTION TO FLOPPY

A floppy disk is a data storage medium that is composed of a disk of thin, flexible("floppy") magnetic storage medium encased in a square or rectangular plastic shell.

Floppy disks are read and written by a floppy disk drive or FDD, [2] Invented by theAmerican information technology company IBM, floppy disks in 8 inch, 5 inch and 3inch forms enjoyed nearly three decades as a popular and ubiquitous form of data storage andexchange, from the mid-1970s to the late 1990s. While floppy disk drives still have somelimited uses, especially with legacy industrial computer equipment, they have now beensuperseded by USB flash drives, external hard disk drives, CDs, DVDs, Blu Ray discs,memory cards and computer networks.

A small motor in the drive rotates the diskette at a regulated speed, while a second motor-operated mechanism moves the magnetic read/write head,(or heads, if a double-sided drive)

along the surface of the disk. To write data onto the disk, current is sent through a coil in thehead. The magnetic field of the coil magnetizes spots on the disk as it rotates; the change inmagnetization encodes the digital data. To read data, the tiny voltages induced in the headcoil by the magnetization on the disk are detected, amplified by the disk drive electronics,and sent to the Floppy disk controller. The controller separates the data from the stream of

pulses coming from the drive, decodes the data, tests for errors, and sends the data on to thehost computer system.

A blank diskette has a uniform featureless coating of magnetic oxide on it. A pattern ofmagnetized tracks, each broken up into sectors, is initially written to the diskette so that thediskette controller can find data on the disk. The tracks are concentric rings around the

diskette, with spaces between the tracks where no data is written. Other gaps, where no userdata is written, are provided between the sectors and at the end of the track to allow for slightspeed variations in the disk drive.

USAGES:

The flexible magnetic disk, commonly called floppy disk, revolutionized computer diskstorage for small systems and became ubiquitous in the 1980s and 1990s in their use with

personal computers and home computers to distribute software, transfer data, and createbackups. In general, different physical sizes of floppy disks are incompatible by definition,and disks can be loaded only on the correct size of drive. There were some drives available

with both 3-inch and 5-inch slots that were popular in the transition period between thesizes.

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CD & DVDS

A CD-RW (Compact Disc-Rewritable) is a rewritable optical disc format. Known as CD-Erasable (CD-E) during its development, CD-RW was introduced in 1997, and was preceded

by the CD-MO, which was never officially released, in 1998.

CD-RW discs require a more sensitive laser optics. Also, CD-RWs cannot be read in someCD-ROM drives built prior to 1997. This is why CD-ROM drives of the age must bear a"MultiRead" certification to show compatibility. CD-RW discs need to be blanked beforereuse. Different blanking methods can be used, including "full" blanking in which the entiresurface of the disc is cleared, and "fast" blanking in which only meta-data areas are cleared:PMA, TOC and pregap, comprising a few percent of the disc. Fast blanking is much quicker,and is usually sufficient to allow rewriting the disc. Full blanking removes traces of theformer data, often for confidentiality. It may be possible to recover data from full-blankedCD-RWs with specialty data recovery equipment[citation needed]; however, this is generallynot used except by government agencies due to cost.

CD-RW also have a shorter rewriting cycles life (ca. 1,000) compared to virtually all of thepreviously exposed types storage of media (typically well above 10,000 or even 100,000),something which however is less of a drawback considering that CD-RWs are usually writtenand erased in their totality, and not with repeated small scale changes, so normally wearleveling is not an issue.

Their ideal usage field is in the creation of test disks, temporary short or mid-term backups,and in general, where an intermediate solution between online and offline storage schemes is

required.

WORK:

All CDs and DVDs work by virtue of marks on the disc that appear darker than thebackground. These are detected by shining a laser on them and measuring the reflected light.In the case of molded CDs or DVDs, such as those bought in music or video stores, thesemarks are physical pits imprinted into the surface of the disc. In CD-Recordable (CD-R)discs, a computers writing laser creates permanent marks in a layer of dye polymer in thedisc. CD-Rewritable (CD-RW) discs are produced in a similar fashion, except that the changeto the recording surface is reversible.

The key is a layer of phase-change material, an alloy composed of silver, indium, antimonyand tellurium. Unlike most solids, this alloy can exist in either of two solid states: crystalline(with atoms closely packed in a rigid and organized array) or amorphous (with atoms inrandom positions). The amorphous state reflects less light than the crystalline one does.When heated with a laser to about 700 degrees Celsius, the alloy switches from the originalcrystalline phase to the amorphous state, which then appears as a dark spot when the disc is

played back. These spots can be erased using the same laser (at a lower power) to heat thematerial to a temperature of 200 degrees C or so; this process returns the alloy to itscrystalline state. Most CD-RW makers suggest that one disc can be overwritten up to 1,000times and will last about 30 years.

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Prior to the introduction of the CD-RW technology, a standard for magneto-opticalrecordable and erasable CDs called CD-MO was introduced in 1988 and set in the OrangeBook, part 1, and was basically a CD with a magneto-optical recording layer. The CD-MOstandard also allowed for an optional non-erasable zone on the disk, which could be read bynormal CD-ROM reader units.

Data recording (and erasing) was achieved by heating the magneto-optical layer's material(eg. DyFeCo or less often TbFeCo or GdFeCo) up to its Curie point thus erasing all previousdata and then using a magnetic field to write the new data, in a manner essentially identical toSony's MiniDisc and other magneto-optical formats. Reading of the discs relied on the Kerreffect. This was also the first major flaw of this format: it could only be read in special drivesand was physically incompatible with non magneto-optical enabled drives, in a much moreradical way than the later CD-RWs.

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Purpose of storage

Many different forms of storage, based on various natural phenomena, have been invented.So far, no practical universal storage medium exists, and all forms of storage have some

drawbacks. Therefore a computer system usually contains several kinds of storage, each withan individual purpose.

A digital computer represents data using the binary numeral system. Text, numbers, pictures,audio, and nearly any other form of information can be converted into a string of bits, or

binary digits, each of which has a value of 1 or 0. The most common unit of storage is thebyte, equal to 8 bits. A piece of information can be handled by any computer whose storagespace is large enough to accommodate the binary representation of the piece of information,or simply data. For example, using eight million bits, or about one megabyte, a typicalcomputer could store a short novel.

Traditionally the most important part of every computer is the central processing unit (CPU,or simply a processor), because it actually operates on data, performs any calculations, andcontrols all the other components.

Primary Memory

Primary storage (or main memory or internal memory), often referred to simply as memory,is the only one directly accessible to the CPU. The CPU continuously reads instructionsstored there and executes them as required. Any data actively operated on is also stored therein uniform manner.

Historically, early computers used delay lines, Williams tubes, or rotating magnetic drums asprimary storage. By 1954, those unreliable methods were mostly replaced by magnetic corememory. Core memory remained dominant until the 1970s, when advances in integratedcircuit technology allowed semiconductor memory to become economically competitive.

This led to modern random-access memory (RAM). It is small-sized, light, but quiteexpensive at the same time. (The particular types of RAM used for primary storage are alsovolatile, i.e. they lose the information when not powered).

As shown in the diagram, traditionally there are two more sub-layers of the primary storage,

besides main large-capacity

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RAM:

Secondary storage

Secondary storage (or external memory) differs from primary storage in that it is not directlyaccessible by the CPU. The computer usually uses its input/output channels to accesssecondary storage and transfers the desired data using intermediate area in primary storage.Secondary storage does not lose the data when the device is powered downit is non-

volatile. Per unit, it is typically also two orders of magnitude less expensive than primarystorage. Consequently, modern computer systems typically have two orders of magnitudemore secondary storage than primary storage and data is kept for a longer time there.

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In modern computers, hard disk drives are usually used as secondary storage. The time takento access a given byte of information stored on a hard disk is typically a few thousandths of asecond, or milliseconds. By contrast, the time taken to access a given byte of informationstored in random access memory is measured in billionths of a second, or nanoseconds. This

illustrates the very significant access-time difference which distinguishes solid-state memoryfrom rotating magnetic storage devices: hard disks are typically about a million times slowerthan memory. Rotating optical storage devices, such as CD and DVD drives, have evenlonger access times. With disk drives, once the disk read/write head reaches the proper

placement and the data of interest rotates under it, subsequent data on the track are very fastto access. As a result, in order to hide the initial seek time and rotational latency, data aretransferred to and from disks in large contiguous blocks.

The secondary storage is often formatted according to a file system format, which providesthe abstraction necessary to organize data into files and directories, providing also additionalinformation (called metadata) describing the owner of a certain file, the access time, theaccess permissions, and other information.

INPUT DEVICES

An input device is any peripheral (piece of computer hardware equipment) used to providedata and control signals to an information processing system (such as a computer). Input andoutput devices make up the hardware interface between a computer as a scanner or 6DOFcontroller.

Many input devices can be classified according to:

Modality of input (e.g. mechanical motion, audio, visual, etc.)The input is discrete (e.g. key presses) or continuous (e.g. a mouse's position, thoughdigitized into a discrete quantity, is fast enough to be considered continuous)The number of degrees of freedom involved (e.g. two-dimensional traditional mice, or three-dimensional navigators designed for CAD applications)Pointing devices, which are input devices used to specify a position in space, can further beclassified according to:

Whether the input is direct or indirect. With direct input, the input space coincides with thedisplay space, i.e. pointing is done in the space where visual feedback or the cursor appears.

Touch screens and light pens involve direct input. Examples involving indirect input includethe mouse and trackball.Whether the positional information is absolute (e.g. on a touch screen) or relative (e.g. with amouse that can be lifted and repositioned)

Output devices

An output device is any piece of computer hardware equipment used to communicate theresults of data processing carried out by an information processing system (such as acomputer) to the outside world.

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In computing, input/output, or I/O, refers to the communication between an informationprocessing system (such as a computer), and the outside world. Inputs are the signals or datasent to the system, and outputs are the signals or data sent by the system to the outside.

PCI (peripheral component interface)

Conventional PCI (part of the PCI Local Bus standard and often shortened to PCI) is acomputer bus for attaching hardware devices in a computer. These devices can take either theform of an integrated circuit fitted onto the motherboard itself, called a planar device in thePCI specification, or an expansion card that fits into a slot. The name PCI is an initialismformed from Peripheral Component Interconnect. The PCI Local Bus is common in modernPCs, where it has displaced ISA and VESA Local Bus as the standard expansion bus, and italso appears in many other computer types. Despite the availability of faster interfaces suchas PCI-X and PCI Express, conventional PCI remains a very common interface.

The PCI specification covers the physical size of the bus (including the size and spacing ofthe circuit board edge electrical contacts), electrical characteristics, bus timing, and protocols.The specification can be purchased from the PCI Special Interest Group (PCI-SIG).

Typical PCI cards used in PCs include: network cards, sound cards, modems, extra ports suchas USB or serial, TV tuner cards and disk controllers. Historically video cards were typicallyPCI devices, but growing bandwidth requirements soon outgrew the capabilities of PCI. PCIvideo cards remain available for supporting extra monitors and upgrading PCs that do nothave any AGP or PCI Express slots.[1]

Many devices traditionally provided on expansion cards are now commonly integrated ontothe motherboard itself, meaning that modern PCs often have no cards fitted. However, PCI isstill used for certain specialized cards, although many tasks traditionally performed byexpansion cards may now be performed equally well by USB devices.

PCI (Peripheral Component Interconnect) was immediately put to use in servers, replacingMCA and EISA as the server expansion bus of choice. In mainstream PCs, PCI was slower toreplace VESA Local Bus (VLB), and did not gain significant market penetration until late1994 in second-generation Pentium PCs. By 1996 VLB was all but extinct, andmanufacturers had adopted PCI even for 486 computers.[2] EISA continued to be usedalongside PCI through 2000. Apple Computer adopted PCI for professional Power Macintosh

computers (replacing NuBus) in mid-1995, and the consumer Performa product line(replacing LC PDS) in mid-1996.

Later revisions of PCI added new features and performance improvements, including a 66MHz 3.3 V standard and 133 MHz PCI-X, and the adaptation of PCI signaling to other formfactors. Both PCI-X 1.0b and PCI-X 2.0 are backward compatible with some PCI standards.

The PCI-SIG introduced the serial PCI Express in 2004. At the same time they rechristenedPCI as Conventional PCI. Since then, motherboard manufacturers have included

progressively fewer Conventional PCI slots in favor of the new standard.

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EXPANSION SLOT

The expansion card (also expansion board, adapter card or accessory card) in computing is aprinted circuit board that can be inserted into an expansion slot of a computer motherboard to

add functionality to a computer system.

One edge of the expansion card holds the contacts (the edge connector) that fit exactly intothe slot. They establish the electrical contact between the electronics (mostly integratedcircuits) on the card and on the motherboard.

Connectors mounted on the bracket allow the connection of external devices to the card.Depending on the form factor of the motherboard and case, around one to seven expansioncards can be added to a computer system. In the case of a backplane system, up to 19expansion cards can be installed. There are also other factors involved in expansion cardcapacity. For example, most graphics cards on the market as of 2010 are dual slot graphicscards, using the second slot as a place to put an active heat sink with a fan.

Some cards are "low-profile" cards, meaning that they are shorter than standard cards andwill fit in a lower height computer chassis. (There is a "low profile PCI card" standard[1] thatspecifies a much smaller bracket and board area). The group of expansion cards that are usedfor external connectivity, such as a network, SAN or modem card, are commonly referred toas input/output cards (or I/O cards).

The primary purpose of an expansion card is to provide or expand on features not offered bythe motherboard. For example, the original IBM PC did not provide graphics or hard drive

capability as the technology for providing that on the motherboard did not exist. In that case,a graphics expansion card and an ST-506 hard disk controller card provided graphicscapability and hard drive interface respectively.

In the case of expansion of on-board capability, a motherboard may provide a single serialRS232 port or Ethernet port. An expansion card can be installed to offer multiple RS232

ports or multiple and higher bandwidth Ethernet ports. In this case, the motherboard providesbasic functionality but the expansion card offers additional or enhanced ports.

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expansion slot shown in fig.,

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RAM

An early type of widespread writable random-access memory was the magnetic corememory, developed from 1949 to 1952, and subsequently used in most computers up until the

development of the static and dynamic integrated RAM circuits in the late 1960s and early1970s. Before this, computers used relays, delay line/delay memory, or various kinds ofvacuum tube arrangements to implement "main" memory functions (i.e., hundreds orthousands of bits), some of which were random access, some not. Latches built out ofvacuum tube triodes, and later, out of discrete transistors, were used for smaller and fastermemories such as random-access register banks and registers. Prior to the development ofintegrated ROM circuits, permanent (or read-only) random-access memory was oftenconstructed using semiconductor diode matrices driven by address decoders.RAM disks

Software can "partition" a portion of a computer's RAM, allowing it to act as a much fasterhard drive that is called a RAM disk. A RAM disk loses the stored data when the computer isshut down, unless memory is arranged to have a standby battery power source.

DDR AND SD RAM

Double data rate synchronous dynamic random access memory (DDR SDRAM) is a class ofmemory integrated circuits used in computers.

Compared to single data rate (SDR) SDRAM, the DDR SDRAM interface makes highertransfer rates possible by more strict control of the timing of the electrical data and clocksignals. Implementations often have to use schemes such as phase-locked loops and self-

calibration to reach the required timing accuracy.[1][2]The interface uses double pumping(transferring data on both the rising and falling edges of the clock signal) to lower the clockfrequency. One advantage of keeping the clock frequency down is that it reduces the signalintegrity requirements on the circuit board connecting the memory to the controller. Thename "double data rate" refers to the fact that a DDR SDRAM with a certain clock frequencyachieves nearly twice the bandwidth of a single data rate (SDR) SDRAM running at the sameclock frequency, due to this double pumping.

With data being transferred 64 bits at a time, DDR SDRAM gives a transfer rate of (memorybus clock rate) 2 (for dual rate) 64 (number of bits transferred) / 8 (number of bits/byte).Thus, with a bus frequency of 100 MHz, DDR SDRAM gives a maximum transfer rate of

1600 MB/s.

"Beginning in 1996 and concluding in June 2000, JEDEC developed the DDR (Double DataRate) SDRAM specification (JESD79)."[3] JEDEC has set standards for data rates of DDRSDRAM, divided into two parts. The first specification is for memory chips, and the secondis for memory modules. DDR SDRAM (sometimes referred to as DDR1 SDRAM) has beensuperseded by DDR2 SDRAM and DDR3 SDRAM.

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DDR SERIES

OLD SD RAM

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MOTHER BOARD

A motherboard is the central printed circuit board (PCB) in many modern computers andholds many of the crucial components of the system, while providing connectors for other

peripherals. The motherboard is sometimes alternatively known as the main board, systemboard, or, on Apple computers, the logic board.[1] It is also sometimes casually shortened tomoboDuring the late 1980s and 1990s, it became economical to move an increasing number of

peripheral functions onto the motherboard (see below). In the late 1980s, motherboards beganto include single ICs (called Super I/O chips) capable of supporting a set of low-speed

peripherals: keyboard, mouse, floppy disk drive, serial ports, and parallel ports. As of the late1990s, many personal computer motherboards supported a full range of audio, video, storage,and networking functions without the need for any expansion cards at all; higher-end systemsfor 3D gaming and computer graphics typically retained only the graphics card as a separatecomponent.

Most computer motherboards produced today are designed for IBM-compatible computers,which currently account for around 90% of global PC sales

A motherboard, like a backplane, provides the electrical connections by which the othercomponents of the system communicate, but unlike a backplane, it also connects the central

processing unit and hosts other subsystems and devices.

A typical desktop computer has its microprocessor, main memory, and other essentialcomponents connected to the motherboard. Other components such as external storage,

controllers for video display and sound, and peripheral devices may be attached to themotherboard as plug-in cards or via cables, although in modern computers it is increasinglycommon to integrate some of these peripherals into the motherboard itself.

An important component of a motherboard is the microprocessor's supporting chipset, whichprovides the supporting interfaces between the CPU and the various buses and externalcomponents. This chipset determines, to an extent, the features and capabilities of themotherboard.

Modern motherboards include, at a minimum:

Sockets (or slots) in which one or more microprocessors may be installed.Slots into which the system's main memory is to be installed (typically in the form ofDIMM modules containing DRAM chips)

A chipset which forms an interface between the CPU's front-side bus, main memory, andperipheral buses

Non-volatile memory chips (usually Flash ROM in modern motherboards) containing thesystem's firmware or BIOS

A clock generator which produces the system clock signal to synchronize the variouscomponents

Slots for expansion cards (these interface to the system via the buses supported by the

chipset)

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Power connectors, which receive electrical power from the computer power supply anddistribute it to the CPU, chipset, main memory, and expansion cards

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Additionally, nearly all motherboards include logic and connectors to support commonlyused input devices, such as PS/2 connectors for a mouse and keyboard. Early personalcomputers such as the Apple II or IBM PC included only this minimal peripheral support onthe motherboard. Occasionally video interface hardware was also integrated into themotherboard; for example, on the Apple II and rarely on IBM-compatible computers such as

the IBM PC Jr. Additional peripherals such as disk controllers and serial ports were providedas expansion cards.

Given the high thermal design power of high-speed computer CPUs and components, modernmotherboards nearly always include heat sinks and mounting points for fans to dissipateexcess heat.

CPU SOCKETS

A CPU socket or slot is an electrical component that attaches to a printed circuit board (PCB)and is designed to house a CPU (also called a microprocessor). It is a special type ofintegrated circuit socket designed for very high pin counts. A CPU socket provides manyfunctions, including a physical structure to support the CPU, support for a heat sink,facilitating replacement (as well as reducing cost), and most importantly, forming anelectrical interface both with the CPU and the PCB. CPU sockets can most often be found inmost desktop and server computers (laptops typically use surface mount CPUs), particularlythose based on the Intel x86 architecture on the motherboard. A CPU socket type andmotherboard chipset must support the CPU series and speed. Generally, with a newer AMDmicroprocessor, you need only select a motherboard that supports the CPU and not beconcerned with the chipset.

INTERGRATED PERIPHERALS

With the steadily declining costs and size of integrated circuits, it is now possible to includesupport for many peripherals on the motherboard. By combining many functions on onePCB, the physical size and total cost of the system may be reduced; highly integratedmotherboards are thus especially popular in small form factor and budget computers.

For example, the ECS RS485M-M, a typical modern budget motherboard for computersbased on AMD processors, has on-board support for a very large range of peripherals

disk controllers for a floppy disk drive, up to 2 PATA drives, and up to 6 SATAdrives (including RAID 0/1 support)

integrated ATI Radeon graphics controller supporting 2D and 3D graphics, with VGAand TV output

integrated sound card supporting 8-channel (7.1) audio and S/PDIF output

Fast Ethernet network controller for 10/100 Mbit networking

USB 2.0 controller supporting up to 12 USB ports

IrDA controller for infrared data communication (e.g. with an IrDA-enabled cellularphone or printer)

temperature, voltage, and fan-speed sensors that allow software to monitor the health

of computer components

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TEMPERATURE AND RELIABILITY

Motherboards are generally air cooled with heat sinks often mounted on larger chips, such asthe Northbridge, in modern motherboards. If the motherboard is not cooled properly, it can

cause the computer to crash. Passive cooling, or a single fan mounted on the power supply,was sufficient for many desktop computer CPUs until the late 1990s; since then, most haverequired CPU fans mounted on their heat sinks, due to rising clock speeds and powerconsumption. Most motherboards have connectors for additional case fans as well. Newermotherboards have integrated temperature sensors to detect motherboard and CPUtemperatures, and controllable fan connectors which the BIOS or operating system can use toregulate fan speed. Some computers (which typically have high-performancemicroprocessors, large amounts of RAM, and high-performance video cards) use a water-cooling system instead of many fans.

BIOS

Motherboards contain some non-volatile memory to initialize the system and load anoperating system from some external peripheral device. Microcomputers such as the Apple IIand IBM PC used ROM chips, mounted in sockets on the motherboard. At power-up, thecentral processor would load its program counter with the address of the boot ROM and startexecuting ROM instructions, displaying system information on the screen and runningmemory checks, which would in turn start loading memory from an external or peripheraldevice (disk drive). If none is available, then the computer can perform tasks from othermemory stores or display an error message, depending on the model and design of thecomputer and version of the BIOS.

Most modern motherboard designs use a BIOS, stored in an EEPROM chip soldered to themotherboard, to bootstrap the motherboard. (Socketed BIOS chips are widely used, also.) By

booting the motherboard, the memory, circuitry, and peripherals are tested and configured.This process is known as a computer Power-On Self Test (POST) and may include testingsome of the following devices:

floppy drive

network controller

CD-ROM drive

DVD-ROM drive

SCSI hard drive

IDE, EIDE, or SATA hard disk

External USB memory storage device

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Block diagram

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SMPS

A switched-mode power supply (switching-mode power supply, SMPS, or simply switcher)is an electronic power supply that incorporates a switching regulator in order to be highly

efficient in the conversion of electrical power. Like other types of power supplies, an SMPStransfers power from a source like the electrical power grid to a load (e.g., a personalcomputer) while converting voltage and current characteristics. An SMPS is usuallyemployed to efficiently provide a regulated output voltage, typically at a level different fromthe input voltage.

Unlike a linear power supply, the pass transistor of a switching mode supply switches veryquickly (typically between 50 kHz and 1 MHz) between full-on and full-off states, whichminimizes wasted energy. Voltage regulation is provided by varying the ratio of on to offtime. In contrast, a linear power supply must dissipate the excess voltage to regulate theoutput. This higher efficiency is the chief advantage of a switch-mode power supply.

Switching regulators are used as replacements for the linear regulators when higherefficiency, smaller size or lighter weight are required. They are, however, more complicated,their switching currents can cause electrical noise problems if not carefully suppressed, andsimple designs may have a poor power factor.

A modern computer power supply is a switch with on and off supply designed to convert110-240 V AC power from the mains supply, to several output both positive (and historicallynegative) DC voltages in the range + 12V,-12V,+5V,+5VBs and +3.3V. The first generationof computers power supplies were linear devices, but as cost became a driving factor, andweight became important, switched mode supplies are almost universal.

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ATX shown in fig;

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UNIT 4

TROUBLESHOOTING

1. RAM PROBLEM:

System give 3 short beeps like 1-1-1

No display means ( monitor cannot receive signal from mother board )

BLUE SCREEN ERROR

System alt ( hang )

Solve:

Remove the ram from ram slot clear the ram.

If noDisplay

change the ram slot. Or change the ram

BLUE SCREEN ERRORdid u see if ram memory failure CHANGE THE RAM

If system alt cannot boot remove and clear the ram and slot also clear temp files.2. PROCESSOR PROBLEM:

if processor failure you can receive 5 short beep 1 1 1 1 1 1 1 1 1 1No Display also

Capacitor problem.

Solve:

Receive 5 beep change the processor (ALSO NO DISPLAY)If capacitor problem change that related capacitor

3. BIOS PROBLEM:

System can restart

System cannot Start

Keyboard halt etc.,

hard disk or device detection problem.

boot device problem also.

Solved:

Clear the CMOS or BIOS using jumpers

config the bios jumpers.

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4. NO DISPLAY PROBLEM:

Change the ram

Change the processor

Petrol washes the mother board

Clear the bios

Check the power supply in and out using multimeter

Check southern bridge

Check PCI slots

Check IDE & FDD connectors

Check the capacitors

check fan & heat sink.

OPERATING SYSTEM

INSTALLATION XP:

First check the bios booting devices DVD & HARD DISK

Assign the 1, 2, 3 ndbooting devices.

Insert WINDOWS XP in to the DVD or CD Drive

In screen PRESS ANY KEY TO CONTINUE. . . . . Press any key in key board.

Enter to XP INSTALLATION will start.

Press Enter to Welcome screen

Press F8 - I AGREE To continue for license agreement.

IF new hard disk they to enter to the partition if no hard disk is old ask this questionC:\WINDOWS\SYSTEM32\ press ENTER TO CONTINUE.

You will enter in partition options

After you create partition go to c:\ press ENTER

He ask 4 questions Like this QUICKNTFS, QUICKFAT, NTFS, FAT, Leave changesIf put NTFS quick format.

After 39minutes will start

Click NEXT

Click Next for Language and keyboard

Enter PRODUCT ID Click Next

Enter date and Time zone. Click NextEnter Network option click Next

After complete the Setup in Welcome screen in Windows XP.

Then OPERATING SYSTEM INSTALLATION COMPLETED

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UNIT -5

INTRODUCTION TO NETWORKING

What is a Network?

A computer network is simply two or more computers connected together so they canexchange information. A small network can be as simple as two computers linked together bya single cable.

Building a Simple Network

Most networks use hubs to connect computers together. A large network may connectthousands of computers and other devices together.

What Can I do With a Simple Network?Without a network, you can access resources only on your own computer. These resourcesmay be devices in your computer, such as a folder or disk drive, or they may be connected toyour computer, such as a printer or CD-ROM drive. These devices, accessible only to you,are local resources.

Networking allows you to share resources among a group of computer users.

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Sharing Files and Drives

If your computers are connected to a network, each computer can make its resourcesavailable to other computers in your office by sharing them over the network. Instead of

working in isolation as you do on a single computer not linked to a network, you can workcollectively, within a system that shares resources among a group of computer users.Each computer on your network can share folders, entire disk drives, or a CD-ROM drive.Then other computers on your network can access documents and other files stored in thefolders and on the drives. Instead of copying a document to a diskette and giving it to another

person to view, anyone can open and view the document using the network.If you want to view the company's annual report stored on a co-worker's computer, you canuse the network to access the document on that computer. If you want to listen to musicstored on a computer in another room, you can use the network to access the music files.

Sharing a Printer

If you have a printer connected to your computer, you can share the printer with othercomputers on the network. Then instead of buying a printer for every computer, all thecomputers can print across the network to the printer. Suppose you want to print a documenton a color laser printer that is connected to another computer in the office. Instead of copyingyour file to a disk, going to the other computer, and interrupting the person using thatcomputer, you can print directly over the network.

Sharing an Internet Connection

If you already have access to the Internet from one computer on your network, you can sharethat Internet connection with other computers on the network. Then all the computers on yournetwork can browse the Web at the same time, using this single Internet connection.

Networking Components

To network computers together, you need to install networking hardware and software. Everynetwork includes these three components:

The computers that are connected together. Computers and similar devices are callednodes when connected to a network.

The networking hardware that connects the computers together, including hardware

installed in your computer, network cables, and devices that connect all the cables together.Networking software that runs on each computer and enables it to communicate with

other computers on the network.

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Networking Hardware

Here is the networking hardware you need to set up a small network: Network adapter cards:expansion cards that provide the physical connection between each computer and the

network. The card installs into a slot on your computer, just like a sound card or modem card.Some newer computers have a network adapter already built into the system. Laptopcomputers often use a card that slides into a PC card slot.

Network cables: special, unshielded twisted-pair (UTP) cables used to connect eachcomputer to the hub. The cable you need is Category 5 UTP cable with a square plastic RJ-45connector on each end.

All the networking hardware described here is known as Ethernet. Ethernet is the industry-wide standard for computer networks. Standard Ethernet networks transmit data at 10 million

bits per second (Mbps). A newer Ethernet standard, called Fast Ethernet, transmits data at100 Mbps. Computer networks often contain a mixture of 10 Mbps and 100 Mbps devices.

Types of Networks

The type of network described in this book is a simple local network, often called a local areanetwork or LAN. A LAN connects computers together at one location.Small Peer-to-Peer NetworksYou can build a simple, small network without using the complex and expensive equipmentused in large networks. On such a network, often called apeer-to-peer network, eachcomputer can communicate with any other computer on the network.

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You can connect computers together using network cables and a hub, or use wirelesstechnology to network the computers.The focus of this book is on building a simple peer-to-peer network. Peer-to-peer networksare easy to install and maintain, and they give you many of the advantages of a large network.A peer-to-peer network is the obvious choice for a network in a home or small office. Youcan set up this network yourself, without buying an expensive server, and without paying forthe services of a network administrator to install and manage the network.Peer-to-peer networking has gained recent popularity on the Internet. Computers connected tothe Internet communicate directly with each other and share files. The software to set up alocal peer-to-peer network has been included in Windows since the release of Windows 95.People have been building simple peer-to-peer networks since that time, using the software

built into Windows.clients on the network access the servers to log on, access files, and print documents. Theservers may be running networking software from Novell or Microsoft, or they may berunning the UNIX or Linux"!" operating systems.

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Large networks are usually constructed by connecting several small networks together withspecial networking equipment that controls communication between the smaller segments ofsubnetworks or SubnetsA ring network is a network topology in which each node connects to exactly two other

nodes, forming a single continuous pathway for signals through each node - a ring. Datatravels from node to node, with each node along the way handling every packet.

Advantages

Very orderly network where every device has access to the token and the opportunity totransmitPerforms better than a star topology under heavy network loadCan create much larger network using Token RingDoes not require network server to manage the connectivity between the computers

Disadvantages

One malfunctioning workstation or bad port in the MAU can create problems for the entirenetworkMoves, adds and changes of devices can affect the network

Network adapter cards and MAU's are much more expensive than Ethernet cards and hubsMuch slower than an Ethernet network under normal load

REMOTE CONNECTION

Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft, whichconcerns providing a user with a graphical interface to another computer.Microsoft currently refers to their official RDP server software as Remote Desktop Services,

formerly "Terminal Services". Their official client software is currently referred to as RemoteDesktop Connection, formerly "Terminal Services Client".

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UNIT-6

COMPUTER VIRUS AND MAINTEANCE

A computer virus is a computer program that can copy itself and infect a computer. The term

"virus" is also commonly but erroneously used to refer to other types of malware, includingbut not limited to adware and spyware programs that do not have the reproductive ability. Atrue virus can spread from one computer to another (in some form of executable code) whenits host is taken to the target computer; for instance because a user sent it over a network orthe Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USBdrive.

Viruses can increase their chances of spreading to other computers by infecting files on anetwork file system or a file system that is accessed by another computer.

As stated above, the term "computer virus" is sometimes used as a catch-all phrase to includeall types of malware, even those that do not have the reproductive ability. Malware includescomputer viruses, computer worms, Trojan horses, most rootkits, spyware, dishonest adwareand other malicious and unwanted software, including true viruses. Viruses are sometimesconfused with worms and Trojan horses, which are technically different. A worm can exploitsecurity vulnerabilities to spread itself automatically to other computers through networks,while a Trojan horse is a program that appears harmless but hides malicious functions.Worms and Trojan horses, like viruses, may harm a computer system's data or performance.Some viruses and other malware have symptoms noticeable to the computer user, but manyare surreptitious or simply do nothing to call attention to themselves. Some viruses donothing beyond reproducing themselves

The first academic work on the theory of computer viruses (although the term "computervirus" was not invented at that time) was done by John von Neumann in 1949 who heldlectures at the University of Illinois about the "Theory and Organization of ComplicatedAutomata". The work of von Neumann was later published as the "Theory of self-reproducing automata".[5] In his essay von Neumann postulated that a computer programcould reproduce

In order to avoid detection by users, some viruses employ different kinds of deception. Someold viruses, especially on the MS-DOS platform, make sure that the "last modified" date of ahost file stays the same when the file is infected by the virus. This approach does not foolanti-virus software, however, especially those which maintain and date Cyclic redundancy

checks on file changes.

Some viruses can infect files without increasing their sizes or damaging the files. Theyaccomplish this by overwriting unused areas of executable files. These are called cavityviruses. For example, the CIH virus, or Chernobyl Virus, infects Portable Executable files.Because those files have many empty gaps, the virus, which was 1 KB in length, did not addto the size of the file.

Some viruses try to avoid detection by killing the tasks associated with antivirus softwarebefore it can detect them.As computers and operating systems grow larger and more complex, old hiding techniques

need to be updated or replaced. Defending a computer against viruses may demand that a filesystem migrate towards detailed and explicit permission for every kind of file access.

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Anti-virus software and other preventive measures

Many users install anti-virus software that can detect and eliminate known viruses after thecomputer downloads or runs the executable. There are two common methods that an anti-

virus software application uses to detect viruses. The first, and by far the most commonmethod of virus detection is using a list of virus signature definitions. This works byexamining the content of the computer's memory (its RAM, and boot sectors) and the filesstored on fixed or removable drives (hard drives, floppy drives), and comparing those filesagainst a database of known virus "signatures". The disadvantage of this detection method isthat users are only protected from viruses that pre-date their last virus definition update. Thesecond method is to use a heuristic algorithm to find viruses based on common behaviors.This method has the ability to detect novel viruses that anti-virus security firms have yet tocreate a signature for.

Virus removal

One possibility on Windows Me, Windows XP, Windows Vista and Windows 7 is a toolknown as System Restore, which restores the registry and critical system files to a previouscheckpoint. Often a virus will cause a system to hang, and a subsequent hard reboot willrender a system restore point from the same day corrupt. Restore points from previous daysshould work provided the virus is not designed to corrupt the restore files or also exists in

previous restore points.[33] Some viruses, however, disable System Restore and otherimportant tools such as Task Manager and Command Prompt. An example of a virus thatdoes this is CiaDoor. However, many such viruses can be removed by rebooting thecomputer, entering Windows safe mode, and then using system tools.

Administrators have the option to disable such tools from limited users for various reasons(for example, to reduce potential damage from and the spread of viruses). A virus can modifythe registry to do the same even if the Administrator is controlling the computer; it blocks allusers including the administrator from accessing the tools. The message "Task Manager has

been disabled by your administrator" may be displayed, even to the administrator

Operating system reinstallation

Reinstalling the operating system is another approach to virus removal. It involves eitherreformatting the computer's hard drive and installing the OS and all programs from original

media, or restoring the entire partition with a clean backup image. User data can be restoredby booting from a Live CD, or putting the hard drive into another computer and booting fromits operating system with great care not to infect the second computer by executing anyinfected programs on the original drive; and once the system has been restored precautionsmust be taken to avoid reinfection from a restored executable file.

These methods are simple to do, may be faster than disinfecting a computer, and areguaranteed to remove any malware. If the operating system and programs must be reinstalledfrom scratch, the time and effort to reinstall, reconfigure, and restore user preferences must

be taken into account. Restoring from an image is much faster, totally safe, and restores theexact configuration to the state it was in when the image was made, with no further trouble.

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Hardware Book 1

Documents

Transcript of Hardware Book 1