Computer Hardware

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COMPUTER HARDWARE

Amol Bajpai

Fundamentals of computer .................................................................................................................... 2 Motherboard........................................................................................................................................... 3 Memory................................................................................................................................................. 20 Microprocessor ..................................................................................................................................... 26 Hard Disk ............................................................................................................................................... 33 Floppy Disk ............................................................................................................................................ 38 Optical Media ........................................................................................................................................ 39 Small Computer System Interface (SCSI) .............................................................................................. 44 Data Communication ............................................................................................................................ 48 SCANNER ............................................................................................................................................... 52 Printer ................................................................................................................................................... 55 Keyboard ............................................................................................................................................... 60 Mouse ................................................................................................................................................... 63 Modem.................................................................................................................................................. 65 SMPS (Switch Mode Power Supply) ...................................................................................................... 67 Display Adaptor..................................................................................................................................... 70 Software ................................................................................................................................................ 71 Microsoft Windows Upgrade chart....................................................................................................... 79 File systems ........................................................................................................................................... 80 System Files........................................................................................................................................... 80 Boot sequence in Windows Operating System ..................................................................................... 81 Computer Viruses ................................................................................................................................. 82 Troubleshooting the PC using Beep Codes ........................................................................................... 84

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COMPUTER HARDWARE

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Fundamentals of computer
Definition of Computer
Computer is an electromechanical device which takes input from the user, processes that data and generates an output. Based on the size and power, the computers can be classified into the following categories: 1. Personal Computer-The personal computer is a small, single user computer based on a microprocessor. It consists of a keyboard for entering data, a monitor for displaying output, and a storage device for saving data. 2. Workstation Computer- The workstation is a single user computer like personal computer but it has more powerful microprocessor and higher quality monitor. 3. Mini Computer- A mini-computer is a multi-user computer that can support 10 to 100 of users simultaneously. 4. Mainframe Computer -A mainframe computer is a powerful computer which can support hundreds to thousands multiple users simultaneously. 5. Super Computer- A supercomputer is an extremely fast computer that can perform hundreds of millions of instructions per second.

Users and application of computer
Some of the important uses and application of computers are listed below: 1. Scientific and engineering applications- Computers are used in scientific and engineering applications such as designing circuit, single processor, satellite, flight navigation, medical equipment etc. 2. Education and research- Computers are used in education and research training, developing, e-learning content etc. 3. Business activities- Computers are also used in various business activities such as automating the business process using software like Tally, Word processors, spreadsheet Excel etc. 4. Software development- Computers are largely used for developing software that are further used to automate various task.

Four basic operations of computer
1. Inputting (Input Device – Keyboard, Mouse, Scanner, Microphone, Webcam, Joy Stick, Game Pad, Touch Pad etc.) 2. Processing ( Processor – Pentium{1,2,3,4},Celeron, Dual Core ,Core 2 Due, Core 2 Quad , I3 , I5 , I7, AMD ( Advance Micro Device ) ) 3. Outputting ( Output Device – Monitor , Printer, Speaker ) 4. Storing ( Storage Device – Hard Disk , Pen Drive , Floppy Disk , CD, DVD, Blu-ray Disc, Memory Card )

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Motherboard
Motherboard forms the most significant component of a Computer. It is printed circuit board (PCB) which processes different components for various purposes. The motherboard contains components like the central processing unit (CPU), Basic Input output system (BIOS), memory and, I/O ports, external I/O connectors, I/O controllers, expansion slots, and chipsets. Chipset is an integrated chip which is used to perform various functions of multiple chips. The first introduced the motherboard is the PC-XT (personal computer extended technology) motherboard.

Peripheral Connectors
The peripheral connectors are integrated in the Motherboard in the computer of recent days. The following figure shows the I/O connectors integrated to the motherboard.

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     

PS/2 port is used for connecting PS/2 Keyboard and PS/2 Mouse USB Ports are used for connecting any type of USB device 9 pin D type Serial port is uses for connecting any serial device 25 Pin D type female Parallel port (LPT) is used for connecting Printers 15 Pin D type female VGA(Video Graphic Adaptor) is used for connection VGA cable 15 Pin D type female connectors is used for connecting devices like Joystick

Physical form factors
Form factor of the motherboard refers to the physical layout of the motherboard. It also deals with that types and shapes of cases that are used, and that different power supplies associated with it. Motherboards can be used using two different form factors what with the same functionalities. The various form factors available are:  PC-XT Page 4

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    AT and Baby AT ATX and Micro ATX LPX and Mini LPX NLX

Amol Bajpai

Personal Computer Extended Technology (PC-XT) PC-XT is the first kind of motherboard introduced by IBM. The PC-XT motherboard had socket for placing the processor and other support chips like clock generator, interrupt controller etc., were present and separate chips. The peripheral devices were plugged into PC slot (expansion slot). The XT motherboard is illustrated in the following figure:

AT and Baby AT Before 1997, IBM computers used motherboard of bigger size. Then due to technological advancements, the size of the motherboard was reduced to greater extent. AT form factor was available in old computer which employed 80386 as its microprocessor. AT means advance technology. The main disadvantage of this form factor was size of the board. The width of the motherboard was 12 inches wide. This caused disturbance of the drive bays.

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To come over this problem created by AT form factor, the baby AT form factor was introduced. In the baby AT form factor, the width of the motherboard was reduced from 12 inches to 8.5 inches. This eliminated the problem is that of her associated with overlapping on that drive bays. AT Motherboard

----------------------------------------------------------------------------------------------------------------------------Baby AT

ATX form Factor Due to advancement in technology, a more integrated form factor was designed and specific locations for the keyboard, mouse, I/O ports and Video connectors were defined. ATX form factor was introduced in mid-1990. In ATX motherboards, the expansion slots were placed on separate riser card that are placed in motherboard. This reduces the overall size of motherboard. Along with the size of the motherboard, in the case and power supply is also altered its. Advancements and

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enhancements in the design of ATX motherboard form factor was introduced new features like

1. 2. 3. 4.

Single 20 pin connector for power supply Power supply for blowing air into the case. This would increase the airflow in the case. Limited overlapping between motherboard and the drive bays. Integrated I/O port connectors soldered directly to the motherboard

Micro ATX form Factor Micro ATX form factor was advancement to the ATX form factor and offered some benefits which enhance the overall system design costs by reducing the physical size of motherboard. The size of motherboard was reduced by limiting the number of I/O slots which is available in the motherboard. In Micro ATX form factor, more space for I/O connectors bars are provided at the rear end. So the features of ATX form factor are given below     Integrated I/O connectors 24 pin power connector Better cooling conditions 3.3 Volt power for processor is directly obtained from the power supply unit

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LPX and Mini LPX (Low Profile Extended) These are some other non-standard form factors which are termed as LPX and mini LPX. These categories are used in low profile computers case like the desktop model. The PLX motherboards generally have sound and video to be integrated on the motherboard. This provides a space saving product and the cost is also reduced. But it has own disadvantages. The troubleshooting of the components in this category of motherboard is difficult because of its non-standardization feature. This type of motherboard is not suitable for upgrading and offers poor cooling. NLX (New Low Profile Extended) The motherboard with this form factors is advancement to the LPX design which is designed for low profile systems. The NLX format of motherboard is small in size with 8.8 inch width and 13 inch length. Hence this format of motherboards in suited for low profile desktop cases.

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Parts for Motherboard

1- Socket of Micro Processor

2- Chipsets

3- BIOS

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4- Expansion Slot (PCI Slot, AGP Slot, AMR Slot)

5- IDE Connector

6- USB Connector

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7- SATA Connector

8- FDD Connector

9- Memory Slot

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Chipset and Functions
There are two types of chipsets 1- North Bridge 2- South Bridge North Bridge – North Bridge is controller chip which is used to commutate between the processor, memory the Level 2 Cache memory, the PCI bus and accelerated Graphic Port (AGP). It makes use of the Front Side Bus (FSB) to interact with the different components. The North Bridge is used to provide fast communication between the various components and the processor. South Bridge - The South Bridge controls and manages the slower I/O components like the serial ports, USB ports and the IDE. The south bridge is connected to the PCI bus of the North Bridge

Bus
Bus is electrical connection between different components in a motherboard. The bus is used for transfer of address, data and control signals. The data transfer rate can be enhanced with the speed of the bus. The bus speed is measured in terms of Megahertz (MHz). The speed of the bus refers to the amount of the data that can be transferred across the bus. Types of buses are:1- Data Bus – Data bus is used to send data between devices and memory. The width of the data bus determines the speed of data transfer. The data bus width varies with to processor. The data bus is bidirectional. 2- Control Bus – Control Bus carries control signal form the processor to other devices or memory. This specifies the kind of operations the processor can carry out. The control operations are I/O read, I/O write, Memory Read, Memory write etc. 3- Address Bus – Address bus is used to specify the address of the location to read / Write form I/O devices or memory. Address bus is used to locate the unique locations to get the data. The address is unidirectional. The width of the address bus determines the maximum amount of memory that the processor can access. There is also another type of technology called the Intel Hub Architecture (IHA) which uses two chips called hub controllers. The Hub controllers manage the interaction between the processor and the other components present in the system. The hub controllers are:  Graphic and Memory Controller Hub (GMCH) – Equivalent to North Bridge and the difference if that MCH does not manage the PCI bus. I/O Controller Hub (ICH) – Twice as fast as the south bridge.

Some of the buses are:123456Front Side Bus (FSB) AGP Bus Back Side Bus (BSB) Memory Bus IDE or ATA Bus PCI Bus

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Front Side Bus: - The bus in general refers to the speed of the Front Side Bus (FSB). The FSB connects the CPU to the North Bridge. The speed of the FSB can vary between 66 MHz and 800 MHz. The speed of the Front Side Bus greatly influences the computer’s performance since the processor interacts with the memory controlled by using FSB. AGP Bus: - The AGP Bus connects the video card to the memory and the CPU. AGP bus operates at a speed of 66 MHz Back Side Bus: - The back side bus connects the processor to the L2 Cache. The back side bus is part of the CPU. The speed of the back side bus is depended on the speed of the processor. Memory Bus: - The memory Bus connects the north bridge to the memory IDE or ATA Bus: - The IDE/ATA bus connects the south bridge to the disk drives. PCI Bus: - The PCI bus connects the PCI slots to the south bridge. The speed of the PCI bus is 33 MHz

Standard Expansion Slots
The I/O slots also called as expansion slots are used by peripheral devices to communicate with the processor. The basic system components available in the motherboard will not be able to support all

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the types of peripheral devices. They are used to enhance the features of the PC. The expansion slots can hold expansion cards like the sound card, VGA card, AGP card, Network card etc. It is also possible connect specialized cards like the TV Tuner card, modem etc. The features of the computer can be improved by connecting add on cards to the expansion slots available in the motherboard. There are different types of expansion slots. They are:        PC (Personal Computer) Expansion Slot ISA ( Industrial Standard Architecture ) Expansion Slot MCA ( Micro Channel Architecture ) Expansion Slot Extended Industrial Standard Architecture (EISA) Expansion Slot Video Electronics Standard Architecture (VESA ) Expansion Slot Accelerated Graphics Port (AGP) Expansion Slot Peripheral Component Interconnect (PCI) Expansion Slot Peripheral Component Interconnect Extended (PCI -X) Expansion Slot

PC (Personal Computer) Expansion Slot: - It was the first expansion slot used in
computer it supports 8 bit data bus.

ISA (Industrial Standard Architecture) Expansion Slot: - This slot is use for 16 bit
data transfer rate of 8 MHz Speed. It was used to support processor like 80286, 80386 and Pentium Series it has 98 pins and black in color.

MCA (Micro Channel Architecture) Expansion Slot: - MCA card was introduced with
two new features that is PnP and bus mastering. It was similar to ISA bus and had support of 32 Bit data transfer.

Extended Industrial Standard Architecture (EISA) Expansion Slot: This slot was
used in the Mother Board supporting P1 and P2. It was extended version of ISA with 32 Bit support it has feature like multiple bus mastering .It’s data transfer speed is 8.33 MHz. It has 98 Pins.

Video Electronics Standard Architecture (VESA) Expansion Slot: - It has also 32
bit data Bus. It is used for video card.

Accelerated Graphics Port (AGP) Expansion Slot: - This is used for Graphic Card it
increases the graphic quality of the system. It works at 16 bit at a clock speed of 1.33 MHz

Peripheral Component Interconnect (PCI) Expansion Slot: - It is popular today
and support 32 bit as well as 64 bit it also support PnP and it has 120 pins.

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Peripheral Component Interconnect Extended (PCI -X) Expansion Slot:- This is
the latest version of PCI which operates at 133 MHz and offers 64 bit bandwidth, supports at 1 Gb/sec data transfer rate.

Serial Ports Parallel Port VGA Port PS2 Port USB Port IDE Port FDD Port SATA Port BIOS AGP PCI Game Port AMR

9 Pins 25 Pins 15 Pins 6 Pins 4 Pins 40 Pins 34 Pins 7 Pins 32 Pins 120 Pins 120 Pins 15 Pins 46

IDE/ATA = Integrated Device Electronic/Advance Technology Attachment SATA = Serial Advance Technology Attachment PATA = Parallel Advance Technology Attachment

PCI USB Card

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PCI Sound Card

TV Tuner Card

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LAN Card

PCI Graphic Card

AGP Card

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What is Jumpers?
Jumper is small connector which can be placed between two pins to make electrical connections. The two pins appear on the circuit board and are electrically connected if the jumper is covering those pins.

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IRQ (Interrupt Request Channels)
The expansion for IRQ is Interrupt Request. Different hardware devices use IRQ signal to the processor to catch its attention. For example, whenever a key is pressed, IRQ 1 is generated. This is an indication to the processor that a key press event has occurred and the data is ready to be sent to the CPU. The Interrupt Request signals generated by different devices cannot be sent through the same channel and hence there are unique channels allotted for specific devices. In earlier days, for new devices introduced to the system, the user should configure the IRQ channel manually. But the advancement in technology a concept called Plug and Play emerged which permitted automatic configuration of system resources.

IRQ Channel number IRQ0 IRQ1 IRQ2 IRQ3 IRQ4 IRQ5 IRQ6 IRQ7 IRQ8 IRQ9 IRQ10 IRQ11 IRQ12 IRQ14 IRQ15

Used by System time Keyboard Cascade Controller COM 2/COM4 COM 1/ COM3 Sound Card, Parallel Port 2 LPT 2 Floppy LPT 1 Real Time Clock Redirected to IRQ 2 Available for otter devices SCSI, Video Available Primary IDE Secondary IDE

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Memory
There are two type of Memory 1- Primary Memory 2- Secondary Memory

Primary Memory
12345Data saved for small period of time. Saved small amount of data. Connected to CPU. Fast Data transfer. Example RAM, ROM, Cache memory.

Secondary Memory
12345Data saved permanently. Saves large amount of data. Connected to I/O ports. Slow data transfer. Example Hard Disk, FDD (Floppy Disk Drive), CD ROM, DVD ROM.

Types of Primary Memory

Volatile Memory – Memory which loses data after the power off. Such memory is known as volatile memory. Example- RAM Non-Volatile Memory – The memory which does not losses it data even after power off is called Non-volatile memory. Example- BIOS –ROM

Types of Volatile Memory

RAM (Random Access Memory)-It is a volatile memory which is used to store user’s data and programs for processing at the present time. Example- SRAM, DRAM
Dynamic RAM 1 2 3 4 5 6 Made up of Capacitors Need refreshing It is cheaper in cost Packaging density is high Slower speed Example- EDO RAM, DDR RAM Static RAM Made up of flip flop Does not need refreshing It's costly Packaging density is less Faster speed Example- Cache RAM

Dynamic RAM – Types of SIMM and DIMM 1- Fast Page Mode Random Access Memory (FPM) – 30 pins 2- Extended Data Out Random Access Memory (EDO) – 72 pins 3- Burst Extended Data Out Random Access Memory (BEDO) – 72 pins 4- Synchronous Dynamic Random Access Memory (SD RAM) -168 pins 5- Double Data Rate Random Access Memory (DDR RAM) – 184 pins 6- Double Data Rate 2 Random Access Memory (DDR2 RAM) – 240 pins

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7- Double Data Rate 3 Random Access Memory (DDR3 RAM) – 240 pins 8- Rambus Dynamic Random Access Memory – 184 pins 9- Video Random Access Memory (VRAM) 10- So DIMM (Dual In Line Memory Module) – 144 to 200 pins 11- Micro DIMM (Dual In Line Memory Module)- 144 to 172 pins SIMM (Single Inline Memory Module)-It was first kind of memory which had series of DIP chip solders to a small PCB. They have row of tin or gold contact pin on the edges. Example – 30 Pin – SIMM Module (FPM RAM) 72 Pin – SIMM Module (EDO RAM)

FPM RAM

EDO RAM DIMM (Dual Inline Memory Module)-It is a standard type of memory module used in modern motherboard. It has row of tin or gold contactors on both the edges. Example – DDR, DDR2 RIMM (Rambus Inline Memory Module)-This memory module is used to hold RD RAM. It has 184 pins and SO RIMM has 160 pins connector. FPM (Fast Page Mode DRAM)-It was the original form of DRAM. It was mostly used in 80486 processor and early Pentium processor. It consists of 30 pins single edge connector. It has nine DIP chips on its PCB. EDO DRAM– It is also known as hyper page mode D-RAM. This EDO DRAM was faster than FPM and saves approximately 10 Nano second per cycle. It was available in 72 pins SIMM format. The EDO DRAM was replaces by SDRAM. BEDO-DRAM (Burst EDO Dynamic RAM, 72 pins)-It was extended version of EDO RAM. It was supported only one chipset (Intel 440 Fx). This RAM could not become so popular

SD-RAM-Introduced in 1990, it was available with bus speed of 66 MHz and later upgraded to 100 MHz and 133 MHz it was the very first DIMM standard memory module. This type of DRAM operates in synchronization with the memory bus. It has less latency period.

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DDR RAM – It was introduced in 2002 and was improved form of SDRAM. It supports P III, P IV, AMD (Advance Micro Devices) and Celeron processor with a bus speed of 400 MHz. It transfers the data twice the speed of SD RAM. It consists of 184 pins. DDR2 RAM (SD DDR2) It is the next generation of DDR SDRAM. It is designed to consume less power in comparison to DDR SD RAM. It is superior to DDR SD RAM. It operates high clock speed with grater signal. These DIMM modules consist of 240 pins. DDR3 SD RAM-It consists of 240 pins same as DDR2 SD RAM but the notch is different place so that it can be distinguished. Rambus DRAM – It’s a completely new technology which supports RIMM slot. It was only standard supported by Intel P-IV motherboard. In this way it never becomes popular. It consists of 184 pins RIMM format. It works at 64 bit Pentium Processor mostly the RIMM slot version was in blue in color. Video RAM-It is used to store image data for processing by the video adaptor. The more memory of the video adaptor creates the better image. Video RAM allows adaptor to display high resolution. It is also known as MPD-RAM (Multi Port Dynamic RAM). SO- DIMM (Small Outline DIMM) - 144 to 200 pins-It is a small form factor of DIMM format. It is generally used in Laptop. Micro DIMM (144 to 172 Pins) –It is a small form factor of DIMM format. It is generally used in notebooks. (Complementary Metal Oxide Semiconductor RAM)-There is a small amount of memory used by the system and other device to store the hardware list and configuration of the system. This memory uses a small battery (CMOS Battery) to provide it with power to maintain memory contents.

Non-Volatile
ROM (Read only Memory) Read only memory is a type of memory used in computer to store data permanently. The data can be read form ROM but can’t be written into it normally. The data in the ROM can’t be erased easily but uses special techniques to erase it. Page 22

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Characteristics of ROM– 1- ROM is non-volatile. 2- ROM uses special technique to write and erase data into them. 3- ROM is slower than RAM. 4- ROM is a firmware and it is used to store system level program. Types of ROM – 1- ROM(Read Only Memory) 2- P-ROM (Programmable Read only Memory) 3- EP-ROM (Erasable Programmable Read Only Memory) 4- EEP-ROM (Electrically Erasable Programmable Read Only Memory)

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ROM - Read only memory is type of memory used in computer to store a small amount of data permanently. ROM can be program only once by the manufacturer. It can be used only for specific function and application without any change. P-ROM – P-ROM is a type of ROM which can be written using some special techniques and equipment. EP-ROM – EP- ROM is an expensive ROM which stores the data for system memory. EP-ROM chip is provided with glass window through which the chip can be programmed many times by passing ultraviolet Rays through them for a defined period of time.

EEP-ROM- EEP-ROM is more advance them P-ROM and EROM you cannot erased from the chip either by Passing Electrically through them under software mostly EEP-ROM is used as storing BIOS programs.

Flash Memory Flash memory is a nonvolatile memory which can be erased and reprogrammed easily. Flash memory is a version of EPROM which erases and writes the data.

Static RAM

Cache Memory-

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Cache Memory is an example accessed easily and quickly by the processor. The more frequently more data is stored in cache memory. Cache memory is limited and expansive. L1 Cache (Level Cache) - It is also known as primary cache and is build inside the processor that so it is the fastest cache memory. L2 Cache (Level -2 Cache) - It is also known as secondary cache, It is present in separate chip on the Motherboard. It has the same working as the L2 Cache but it is less fast then L1 Pentium processor have L2 cache up to 512 KB. L3 Cache (Level -3 Cache) - With the advance next of the technology in the modern computer on extra cache memory which Interfaces, the processor and main memory on the system, It is also known as L3 cache. Disk Cache- Disk cache is the portion of hard disk or portion of RAM, which used to store recently used data or the data accessed next. This enhances the performance of the system by reducing the time taking to read, write to the hard disk, as the disk cache is expensive. It used in small amount.

Hit cache and Miss cache
When a processor request for a data is the present in cache memory then the processor in the cache memory, then is the present data from the cache and is called cache hit. If the data is not available in the cache memory, the processor has to access the main memory for data, this is called miss cache.

Right Back Policy- In this processes the processor after processing any data places the output
into the cache memory. After saving it for some time the cache transfer the data into main memory (RAM). Write through Policy- In this process the output is written on both main memory as well as cache memory simultaneously write through policy reduces the risk of data loss.

Booting- Booting is the process of loading of operating system into system memory. The system
can be booted two ways.

Cold Boot and Hard Boot- Booting the system by turning on the power switch. The system is
start from the switch off state the components present in the motherboard is rest during cold boot. When we restart computer using restart command given by OS then computer performs hard boot. In hard boot BIOS does not performs POST (Power On Self-Test). Paging File- Paging is a technique of implanting virtual memory that known as paging file.

Virtual Memory – That part of hard disk which is used by the system addition system memory
(RAM).In other word we can say that is process a swapping of the programs and data between the RAM and hard disk to execute size then RAM.

Shadow RAM- Shadow is the process of copping of ROM to RAM. The content of BIOS ROM is
copied into RAM and is called shadow ROM.

Memory Errors

1- Hard Error- In hard error the hardware may be faulty and the output always returns to Zero (0). Even the data is stored in it. The hard error may include load defective motherboard etc. 2- Soft Errors- Also Known as transient errors soft errors are caused by the sensors occasionally in correct data from the motherboard. Soft errors are not repeated and also not easy to diagnose to overcome these types of errors.

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Parity and Non Parity

Non Parity- Non parity is a normal memory that contains one bit memory to save one bit data. Non parity modules do not provide any error detection or correction to check data. Parity- Parity is used for error detraction or correction. In parity memory one bit is added in extra to bit data, parity checking is used no correction 1 bit correction detect single bit error in the memory system parity can not be used to detect more than one bit error.

Techniques to overcome memory errors

ECC – Parity can not be used to detect more than one bit errors. Hence a different technique is used to correct the errors. The techniques to correct one bit error and detect multi bit error are called ECC. ECC makes larger grouping like seven bit for protect 32 bit data.

Memory Banks
Memory banks are the collection of modules or socket to from a single logical unit memory chips are arranged in raw in sockets can be considered in same bank or another bank.

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Microprocessor
It is considered as brain of computer. All the processing and controlling of the computer and memory is done by processor. Microprocessor is an electronic component integrated with thousand and millions of transistors for performing arithmetic and logic operations. The Microprocessor is used to perform a variety of functions like executing the instructions given by the user program, controlling the I/O operations and the functions of peripheral devices. Parts of Processing Unit 1- ALU (Arithmetic Logic Unit) – The Arithmetic and Logic Unit (ALU) is used for performing Arithmetic and logic operations. The Arithmetic operations are adding, subtraction, multiplication and division. The logic operations are taking decision based on same conditions. 2- RU (Register Unit) – This part of Microprocessor is used to store data during processing it acts as buffer for processing data. 3- CU (Control Unit) – It provide necessary timing and control signals to all the operations between microprocessor memory and peripherals.

Features of Microprocessor:
1. It is the main component of motherboard. 2. It consists of millions of transistors. (P4 has 5.5 million transistors) 3. It performs functions like mathematical calculation, Logical Comparison and data manipulation.

Qualities of Microprocessor:
 Speed of Processor. Speed of data processing of processor is measured in MHz or GHz. 1 MHz= 1 Million frequency 1 GHz= 1 Billion frequency Note4004 first processor model 8088 first processor used in computer 4004 Processor

8088 Microprocessor

1- The 8088 microprocessor is the first microprocessor used in computer 2- The data bus is 8 bit. It can transfer 8 bits of data at a time. 3- The clock speed supported is 4.77 MHz

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4- It supports the 8087 co-processor. The coprocessor is used for performing floating point related operations and Mathematical Operations.

80286 Processor

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

The width of the address bus is 80286 is 24 bit. Hence it can access 16 MB of memory space. It operates with +5 V DC. It operates with three different frequencies namely 8 MHz, 10 MHz and 12.5 MHz. 80286 support a new concept called virtual memory. Supports Multi-tasking. The co-processor support by 80286 microprocessor is 80287.

80386 Processors

   

Intel 80386 processor is a 32 bit microprocessor. There are two types of 80386 processor. They are 80386 SX and 80386 DX. It can access 4 GB physical address space. Co-processor is supported by both 80386 SX and 80386 DX. The co-processor used is 80387.

80486 Processors
 Intel 80486 is a 32 bit processor. There are two types of 80486 processor. They are 1- 80486 SX 2- 80486 DX

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Differences between 80486 SX and 80486 DX processor 80486 SX The 80486 processor does not have an inbuilt cache memory 80486 SX does not have as inbuilt co-processor. It uses 80486 as its coprocessor

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80486 DX 80486 has 8 Kb of inbuilt cache memory The coprocessor for 80486 DX is inbuilt in the processor

Pentium Processor

The Pentium Processor is a complex and a sophisticated processor when compared to its predecessors. The capabilities of the Pentium processors can be compared to the features of 80486 processor with some improvements. For example there is two separate cache memory of 8 Kb each to support data and code.

Cyrix 686 Processor

The Cyrix 686 processor is the cost effective alternative to Pentium. Cyrix P20+ was the first processor to cross the system bus speed of MHz in operation. The table below show different models of Cyrix processor and the speed of operation. Cyrix Model P 120+ P 133+ CPU Speed 100 MHz 110 MHz System Bus Speed 50 55

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P 166+ P 200+ 133 MHz 150 MHz 66 75

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AMD Processor
The AMD processors are another brand and offer a tight competition to the Intel Processors. The AMD processors operates using a separate technology and hence are not clones of the Intel Processor. AMD processors: 1- AMD Opteron processor – Server and Workstations 2- AMD Athlon 64 processor – Desktop and Notebooks 3- AMD Turion 64 mobile technology – Notebooks

CO PROCESSOR

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IT is also known as floating point unit (FPU) or co-processor.

Amol Bajpai

The main function co-processor is to relief the main processor from calculation and speeding the other computer operation. Co-processor performs high level mathematical calculation using non-integers. Such as long division and complex functions like Trigonometry and logarithm. The co-processor speed is 10000 times faster than processor. Earlier co-processor like 80886, 80286, and 80386 had co-processor built on the motherboard. Intel introduced 8048 DX processor with built in micro co-processor inside processor. After that all the fifth generation processor had integrated co-processing with processor.

Processor 8086 8088 80286 80386sx 80386dx 80486sx 80486dx

Coprocessor 8087 8087 80287 80387sx 80387dx 80487sx,dx2 Dx2

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CPU type
Pentium P1 P2 (i) P2 (ii) P3 (i) P3 (ii) P4 (i) P4 (ii) P4 (iii) P4 (iv) Celeron (i) (ii) (iii) (iv) Athlon (AMD) (i) (ii) (iii) Cyrix (i) (ii) BELOW 550 MHz ABLOE 550 MHz

CPU range

Bus support

100,133,166,200,233 MHz 233,266,300,333,350 MHz 400,450 MHz 450,500,550,600,633,650,666,700 MHz 733,766,800,833,866,933,966MHz(1,1.1,1.2GHz) 1.4,1.5,1.6,1.7 GHz 1.8,1.9,2,2.2 GHz 2.4,2.6 GHz 2.6,2.8,3.0 HT GHz

66 MHz 66 MHz 66-100 MHz 100 MHz 133 MHz 266 MHz 266,333 MHz 333,533 MHz 533,800 MHz

266,300,333,350,400,433 MHz 450,500,533,550,600,650 MHz 700,750,800,850,900 MHz 950MHz, 1,1.3 GHz

66 MHz 66-100 MHz 100 MHz 133 MHz

1800,2000,2100,2200 MHz 2400,2600,2800 MHz 3000,3200 MHz

266-333 MHz 333-533 MHz 533-800 MHz

75 MHz 133 MHz

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VRM Technology
From socket 7 onwards a new technology was implemented known as VRM (Voltage Regulation Module). For sockets other than Socket7, Auto VRM technique is used. It is a technique to make the microprocessor work at a low voltage state. Socket 4 microprocessor used to work at 5 volt. After VRM technology was introduced microprocessor could work at a voltage as low as 3.3 volt for socket 7$ 8 and 2.5 to volts for rest of the sockets.

Chip class Intel/AMD 486 class

Socket/slot Socket 1 Socket 2 Socket 3 Socket 6

Pin 169 238 237 235

Layout 17x17 PGA 19x19 PGA 19x19 PGA 19x19 PGA

Voltage 5 Volt 5 Volt 5 V/3.3V 3.3 V

Supported processor 486Sx/Sx2,dx/dx2,dx4.OD, 486Sx/Sx2,dx/dx2,dx4OD,486 Pentium OD 486x/Sx2,dx/dx2,dx4OD,486 Pentium OD,AMD 5x86 486,dx4,486 Pentium OD

Intel /AMD 586(Pentium class)

Socket 4 Socket 5 Socket 7

273 320 321

21x21 PGA 37X37 PGA 32X37 PGA

5 Volt 3.3 V/3.5 V VRM

Pentium 60/66,OD Pentium 75 - 133,OD Pentium 75-233+,MMX,OD,AMD,K5/K6,cyrix M I/II

Intel 686 Pentium II/III CLASS

Socket 8 Slot I(sc242) Socket 370

387 242 370

Dual-Pentium SPGA Slot

Auto VRM Auto VRM Auto VRM

Pentium Pro, OD Pentium II/III,Celeron SECC Celeron /Pentium III PGA/FC-PGA

Intel Pentium 4 class

Socket 423 Socket 478 Socket –T (LGA775)

423 478 775

39X39 SPGA 26X26 MPGA 30X33 LGA

Auto VRM Auto VRM

Pentium 4, FC-PGA Pentium 4, Celeron FC-PGA 2 Pentium 4, Celeron LGA 775

AMD K7 Class AMD K8 Class

Slot A Socket a (462) Socket 754 Socket 939 Socket 940

242 462 754 939 940

Slot 37*37 SPGA 39*39 mPGA 31*31 mPGA 31*31 mPGA

Auto VRM Auto VRM Auto VRM Auto VRM Auto VRM

AMD Athon SECC AMD Athlon,Athlon XP, Duron PGA, FC-PGA AMD Athlon 64 AMD Athlon 64 v2 AMD Athlon 64 FX Opteron

Intel/AMD Server and Workstation Class

Slot 2(SC330) Socket 603 Socket 604 Socket PAC418 Socket PAC611 Socket 940

330 603 604 418 611 940

Slot 31*25 mPGA 31*25 mPGA 31*22 PGC 25*28 PAC 31*31 mPGA

Auto VRM Auto VRM Auto VRM Auto VRM Auto VRM Auto VRM

Pentium ll/lll Xeon Pentium 4 Xeon Pentium 4 Xeon Itanium Itanium 2 AMD Athlon 64 FX, Opteron

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Hard Disk
Hard Disk is a secondary storage device which is used to save data, operating system etc, in the computer permanently. It storage medium is a round disk made up of glass, aluminum and other and magnetic elements. This disk is known as platter.

Feature of Hard Disk-

1- Storage Capacity- The storage capacity of the hard disk refers to the amount of disk space that can be the user data and the programs in the hard disk. It is usually measured in Giga bytes. 2- Data Transfer speed – There are two ways to measure the speed of the disk drive A- Average seek time – Average seek time is the average amount of time that it takes to move the head from one cylinder to another casual distance and this is normally measured in milliseconds (ms). B- Transfer Rate- The transfer rate is the speed at which data is transferred to one place from the disk platter and this is more important for system performance. Usually it is calculated in megabytes per second (MBps). 3- Stability – Generally the hard drive’s stability has been measured by Mean Time before Failure (MTBF). The value of MTBF is measured in hours. Today in modern hard disk, the MTBF ranges from 300,000 to 1,200,000 hours.

Hard Disk Drive Components

Platters-It is the media where data stores in the hard disk. It is a round shaped disk mainly made up of aluminum and glass. A platter is similar to a music record and a hard disk has many platters.

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Media Layer – It is a very thin layer made up of magnetic materials. This media layer is few micro inches in thickness. It is the place where actually the data store on the hard disk. Protective Layer – Above the media layer an extra thin protective lubricant layer is on the top, known as proactive layer. It protects the platter from the damage caused by the accidental contact of platter with head or other martial. Arm – The arm is like a shaft which lies over the platter. It‘s function is to move the head or carry the head all along over the platter. Head - Head act as a medium to interface the platter where the data is stored and other part of hard disk. Head has read and writes operations. These heads are mounted on the arm that allows it to move from the outer track of the disk platter to the inner track. Stepper Motor – It use to control the operation of the head on the surface of platter. It is an electronic motor which can step from one location to another location of the platter. The stepper motor is also used in FDD to move the head. Voice coil actuator mechanism – This mechanism is used to move the arm for the proper read and write by the head. In voice coil system and electronic head coil attached to the end of the head. There is no control between the coil and magnate. The coil moved by magnetic power. Spindle Motor – This is responsible for spinning or rotating the platter in the hard disk. At one time the platter can rotate at least 3600 rpm (Revaluation Per minute). Modern hard disk can spin at the speed of 5400 R.P.M. HDD Power connector – Hard disk uses a standard 4 pin male power connector to provide power to the hard disk. It has 4 wire plastic connector, + 5 and +12 volts to different devices of the hard disk. Data Interface Connector - This connector is used to transfer data to the hard disk. Different typed of data interface connectors are used to transfer data in hard disk. Logic Board or P.C.B. – Hard Disk can have more than 1 logic board on it. The logic board controls the movement of spindle motor and head of the hard disk. The board contains data controller chips. This controller chip is made up of small but complicated circuits. Since the data in the Hard disk is stored in busses where the data on the mother board is always in digital or binary format. So the function of the controller chip is to convert the data from magnetic format to digital format while reading and digital format to the magnetic format while writing the data.

Types of H.D.D
1- I.D.E. or A.T.A. (Integrated Device Electronic or Advance Technology Attachment) 40pin and 40 wires, 4 pin Molex power connector. 2- SATA (Serial ATA) 7 pins for data, 15 pins for power. 3- PATA (Parallel ATA) 40 pins and 80 wires. 4- SCSI(Small Computer System Interface) 5- USB HDD (External H.D.D.)

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COMPUTER HARDWARE

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SCSI HDD

IDE Cable

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COMPUTER HARDWARE
IDE Hard Disk

Amol Bajpai

SATA Hard Disk

Page 36

COMPUTER HARDWARE
SATA Cable

Amol Bajpai

Portable HDD

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COMPUTER HARDWARE

Amol Bajpai

Floppy Disk
The floppy disk was very popular for storing data and being able to carry the data with you. Floppy disks are not as popular today because they typically can store only up to 1.44MB of data. Today, one picture from a digital camera will use that much space. A floppy disk has a hard plastic casing with a sliding metal shutter that allows the drive to access the silicon disk inside. The floppy disk comes in different sizes, or formats:

The following table shows a summary of the various floppy disk specifications provided in other sections of this chapter, for each of the five major floppy disk types:

Category

Specification Read/Write Heads (Data Surfaces)

360 KB 5.25" 2 300 RPM

1.2 MB 5.25" 2 360 RPM

720 KB 3.5" 2 300 RPM

1.44 MB 3.5" 2 300 RPM

2.88 MB 3.5" 2 300 RPM

Drive Spindle Motor Speed Controller Minimum Controller Transfer Rate Density Name

250 Kbits/s Double Density (DD)

500 Kbits/s High Density (HD)

250 Kbits/s Double Density (DD)

500 Kbits/s High Density (HD)

1 Mbits/s Extra-High Density (ED)

Media

Floppy Disk Drive

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COMPUTER HARDWARE

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Optical Media
CD-ROM
It is type of PROM. It is used to store data in graphic form or text form. It is a round flat disc having an aluminum layer for data storage. It is also Known as optical storage device the data read and written to it in the light form.

Features of CD ROM
12345Low cost High storage density (500 – 700 MB) High speed of data access It is a removable storage medium Multimedia storage – image, moving image, text, audio data.

Components of CD ROM Drive
1- Head –Head is the basic components of the CDROM drive. It contains a light source a light receptor (Laser photo sensor) the head provide light (Laser) to the disc and receptor reads the refried layer light 780 Nano-millimeter wide. 2- Head Actuator – It holds the head and is responsible for the moment of the head in proper direction. 3- Spindle Motor – This Motor is required to spin the disc. The spindle motor spins the disc at a constant rate of about 800 R.PM. to R.D.M. (Revolution per minute) 4- PCB – PCB is responsible for controlling and coordinating the function of different components of CD ROM drive. It also converts data from light from to digital form and vice versa light. It consists of several IC’s including controller chip.

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COMPUTER HARDWARE

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COMPUTER HARDWARE

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Different type of CD
123456Red book CD – used for audio format (74 Min) Yellow book CD – 650 MB Orange book CD – Supports multisession Green book CD (72 Min ) – Supports audio and video White book CD – Support’s MPEG format Blue Book CD – 700 MB , Better quality

Types of DVD
DVD, also known as Digital Video Disc or Digital Versatile Disc, is an optical disc storage media format

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COMPUTER HARDWARE

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The main types of DVDs that differ as to their capacity are:

First side DVD disc types First layer capacity 4.7 Gb 4.3 Gb 4.7 Gb 4.3 Gb 4.3 Gb Second layer capacity 4.3 Gb 4.3 Gb 4.3 Gb First layer capacity 4.7 Gb 4.7 Gb 4.3 Gb

Second side Second layer capacity 4.3 Gb Total capacity

DVD-5 DVD-9 DVD-10 DVD-14 DVD-18

4.7 Gb 8.6 Gb 9.4 Gb 13.3 Gb 17.2 Gb

DVD-5 - single sided, single layer (disc capacity about 4.7 GB, the working surface of such a disc is situated on one side of it and consists of one layer only); DVD-9 - single sided, double layer (disc capacity about 8.6 Gb, the working surface of such a disc is situated on one side of it and consists of two layers about 4.3 Gb each); DVD-10 - double sided, single layer on both sides (disc capacity about 9.4 Gb, the working surfaces of such a disc are situated on both its sides and either consists of one layer about 4.7 Gb); DVD-14 - double sided, double layer on one side and single layer on the other side (disc capacity about 13.3 Gb, the working surfaces of such a disc are situated on both its sides and consist of two layers about 4.3 Gb each on one side and one layer about 4.7 Gb on the other side); DVD-18 - double sided, double layer on both sides (disc capacity about 17.2 Gb, the working surfaces of such a disc are situated on both its sides and either consists of two layers about 4.3 Gb each).

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COMPUTER HARDWARE

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Blu-Ray Discs
Blu-ray Disc (BD) is a next-generation optical disc format meant for storage of high-definition video and high-density data. The Blu-ray standard was jointly developed by a group of leading consumer electronics and PC companies called the Blu-ray Disc Association (BDA), led by Sony and Philips. Blu-ray has information capacity per layer of 25 gigabytes.

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COMPUTER HARDWARE

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Small Computer System Interface (SCSI)
Small computer system Interface (SCSI) is a general-purpose interface for connecting different types of devices. It is used to connect high-speed hard disk drive for better performance in computers like network servers. SCSI is a flexible interface which is employed for connecting many devices. It provides a disk interface as well as system level interface permitting many devices to be connected. SCSI interface is a bus type interface which allows multiple devices to be connected. The SCSI can support a maximum of 7 or 15 total devices. Multichannel SCSI adapter are present and it supports 7 or total 15 devices per channel. The SCSI controller also called as host and adopter is an interface between the SCSI bus and the PC system bus. Each device on the bus has an inbuilt controller. The SCSI bus communicates with each device by controller present. A single SCSI bus can support a maximum of 8 or 16 physical units ended they are termed as SCSI IDs. The SCSI host and adopter bars are one of the SCSI IDs and remaining seven or 15 host IDs are available to other devices. It is possible to connect a maximum for host and adopter is in the most of the systems and hence the SCSI interface can now support a maximum of 60 devices (15x4). Do a general adopter can even support twice of the number of devices supported by a single channel. SCSI interface is the fast interface and provide the best performance features suited for workstation, server. The latest Ultra4 SCSI version supports data transfer speed of 320MB/ second. The SCSI device for an example a SCSI hard disk contains the device, controller and the SCSI adopter and all in one circuit. The device can directly connected to the SCSI bus is the SCSI interface is built in the device then it is called as embedded SCSI device. The SCSI devices technically similar to the IDE hard disk and the difference between them the SCSI bus adopter is included to the controller board in SCSI device. SCSI interface is not an essential component for system expansion. It is necessary only when the best performance is essential.

SCSI interface features
The advantages of SCSI are listed below. They are 1. Performance-SCSI supports data transfer rate up to 320 MB/second. It is used for connecting high performance devices like the hard disk drive, CD-RWs and other high speed perishable devices. 2. Connectivity-SCSI interface provides connectivity for internal and external SCSI devices. One SCSI card can support a maximum of 7 or 15 devices per channel. 3. Compatibility-SCSI interface is compatible with the older peripherals and of both the new and old devices can coexist simultaneous with the affecting the, if speed or performance. 4. Reliability-SCSI interface is the most reliable interface when considering the data integrity, component failure and product quality.

Components of SCSI devices
1234SCSI connector /SCSI Host Adaptor/ SCSI Card SCSI Cables Terminator SCSI Devices

SCSI Card – It is a card which is used to connect all the other devices on the SCSI bus and the computer. It is also knows as SCSI host adapter. The SCSI controller is a card used to plug into the slot on the Motherboard or can be built on the computer.

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SCSI Cable - The SCSI Cable can be of two types according to their passion a- Internal SCSI cables b- External SCSI cables Internal SCSI Cables – The Internal SCSI look like IDE cables.

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COMPUTER HARDWARE

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External SCSI Cables – The internal SCSI cable is more thick then internal SCSI cable and is usually round in shape.

Terminator – It is used with SCSI Cable to absorb free signal.

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COMPUTER HARDWARE

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SCSI TYPES Maximum Bits Frequency Transfer Rate Device Support Pins

SCSI (I) original 8 Bits 5 MHz 5 Mbps 8 Devices 25/50 Pins

SCSI(II) Fast 8 Bits 10 MHz 10 Mbps 8 Devices 50 Pins

SCSI(II) Wide 16 Bits 5 MHz 10 Mbps 16 Devices 50 Pins

SCSI(II) Fast/Wide 16 Bits 10 MHz 20 Mbps 16 Devices 68 Pins

SCSI(III) Ultra 8 Bits 20 MHz 20 Mbps 8 Devices 68 Pins

SCSI(III) Ultra/Wide 16 Bits 20 MHz 40 Mbps 8 Devices 68 Pins

SCSI(III) Ultra 2 8 Bits 40 MHz 40 Mbps 8 Devices 68 Pins

SCSI(III) Ultra/Wide 2 16 Bits 40 MHz 80 Mbps 16 Devices 68 Pins

SCSI(III) Ultra 3 16 Bits 40 MHz 160 Mbps 16 Devices 68 Pins

SCSI(III) Ultra32 16 Bits 80 MHz 320 Mbps 16 Devices 68 Pins

There are two types of terminators 1- Active Terminator (Use Power) 2- Passive Terminator (Do not use Power)

Types of SCSI
SCSI Printer

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COMPUTER HARDWARE

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Data Communication
1- Serial Communication- The data is sent bit by bit in serial communication. The data is divided into bits and transmitted in a sequence and at the receiving end each bit is rebuilt to form a complete data. 2- Parallel Communication – The data is sent as types. A specific data is send through a group of wires.

Difference between serial and parallel communication
1 2 3 4 Serial Communication Single wire is used for transmission It is cheaper It is suitable for long distance communication The transmission speed is less Parallel Al least 8 wires are user for transmission. For transmitting of bits on numbers of wires are required. It is costly because At least 8 number of wires required for communication. It is not suitable for long distance communication because it is effected by noise and distortion The transmission speed is high

Types of Serial communication
Serial port is used to transfer single bit of data at a time. The different kinds of serial ports used as I.O ports are 9 pins D type male connecter and 25 pins D type male connecter. A- Simplex mode of communication- This mode of communication the network cable or communication channel can transfer in only one direction. The simplex communication is permanent unidirectional communication. Example Keyboard, Mouse. B- Half Duplex Communication – Half duplex communication can send data in both direction but not simultaneously. In it the communication channel can either receive the data or send the data. Example Willkie – Talkie, Bus topology. C- Full Duplex mode of communication – In this type of communication the data can be send and received by the same channel simultaneously. Example. USB Devices. D- Synchronous Communication – The synchronous mode of transmission is used in computer having same speed of communication. There is gap between two characters and data, bit flow continuously at a very high speed. E- Asynchronous Communication – In this communication the data is send and received with the help of start and stop bits. This mode of communication is used between slow speed devices. F- UART( Universal Asynchronous Receiver cum Transmitter) – The UART received the data form the computer and converts the parallel signals to serial form, also serial signals to parallel form. The UART consist of serial to parallel convertor and parallel to serial converter.

USB (Universal Serial Bus)
It is an I/O port that uses external bus standard and use to connect different external device like Hard Disk, Printer, Mouse, Scanner etc. USB supports plug n play. In USB port 127 devices can be connected in a daisy chain. USB can transfer data at 12 Mbps. While the latest version USB 2.0 can transfer data of the rate of 480 Mbps. Types of USB connector 1- USB A Connector 2- USB B Connector 3- USB mini B connector

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COMPUTER HARDWARE

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USB A connector – It is always connected towards the computer side during the communication. The USB A connector is used at those places where the cable is always attached the device. Example – mouse and keyboard uses A connector.

USB B Connector – The USB B connector used in Printer, Scanner, Modem etc.

USB mini B connector – It is a small form factor of B connecter and is mostly used to provide power and data to device individually or simultaneously.

Device supported by USB –Printer, Scanner, digital camera, mouse, keyboard, speaker, external storage device (such as Pen Drive, HDD), Joy stick and game pad, Network Connector.

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COMPUTER HARDWARE
USB HUB

Amol Bajpai

FireWire IEEE 1394 – FireWire is a fast bus external bus standard. There are mainly two

types of FireWire 1- FireWire 1394a

2- FireWire 1394b

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COMPUTER HARDWARE
USB 2.0 - Capacities

Amol Bajpai

Max. Burst Transfer Rate USB 1.1 12 Mb/s USB 2.0 480 Mb/s FireWire 1394a 400 Mb/s FireWire 1394b 800 Mb/s

Maximum cable length (USB 2.0): 5 meters Maximum cable length (USB 1.1): 3 meters Maximum devices connected in series: 127 The Universal Serial Bus (USB) interface connects computers to mice, digital cameras, scanners, printers, handhelds, and other peripherals. USB 2.0, available on desktop computers and on laptops, raises the data-transfer speed from 12 Mbps to 480 Mbps and brings the technology to the most demanding peripherals, such as camcorders, portable CD-RW drives, or external hard drives. Most new mainstream PCs have at least one USB 2.0 port, which lets you connect not only dozens of new USB 2.0 devices but also the thousands of USB 1.1 devices on the market. Connecting a USB 1.1 device to a USB 2.0 port, however, will still yield a maximum through Put of only 12 Mbps.

Parallel Port – The parallel port is design to communicate with the printer port. PC can have maximum 3 parallel Ports. Connector of parallel port- According to IEEE there are 3 types of connector that can be used in parallel port Type A connector – This type of Connector is found on computer.

Type B connector – Also known as centronic used in interface of printer.

Type C connector – Also called IEEE 1284 standard for parallel port.

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COMPUTER HARDWARE

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SCANNER
Scanner is an input device which converts hard copy into soft copy. In other words we can say that it converts light signal into digital signals.

Types of scanner
1. 2. 3. 4. 5. 6. Flatbed scanner Sheet fed scanner Drum scanner Micro film scanner Slide scanner Digital scanner (Digital camera)

1- Flat Bed scanner – It is the most commonly used scanner. It consists of a light sensor, light source, moving arm and a glass sheet.

2- Sheet fed scanner –It Works same as flatbed scanner but is faster than flatbed scanner for that reason it is expensive. It gives fast speed but the output quality is not very fine. It is used to scan oversized document like maps.

3- Drum Scanner – This scanner provides high quality and high resolution pixel but at high price.

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COMPUTER HARDWARE

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4- Micro Film scanner – This scanner is used to digitalize file rolls of camera. It is very costly.

5- Slide scanner –It is used to scan 3D objects which cannot be scanned to standard scanners.

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COMPUTER HARDWARE

Amol Bajpai

6- Digital Scanner or Camera – It is a combination of scanner with a camera. It is used to improve capturing still and moving images.

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COMPUTER HARDWARE

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Printer
Printer is a hardware device which act as output device and use to convert soft copy into hard copy, is known as printer. In other words we can say that it produces a permanent human readable text or graphic from an electronic format in computer. There are mainly two types of printers

Impact and Non-impact printers
Printers are categorized based on the physical contact of the print head with the paper to produce a text or an image. An impact printer is one where the print head will be in physical contact with the paper. In a non–impact printer, on the other hand the print head will have no physical contact with the paper. The Dot matrix printer is considered as an Impact printer and Laser printer is considered as Non-impact printer. 1- Impact Printer (Daisy Wheel Printer, Drum Printer, Dot Matrix Printer) 2- Non-Impact Printer (Laser Printer , Inkjet printer)

Types of Printer
1- Daisy Wheel Printer (Impact) - It is similar to type writer. It can type letters and alphabets but no graphics. 2- Dot Matrix Printer (Impact) - Create characters by hitting the ink ribbon. 3- Ink Jet printer – It produces graphics and text by spraying ink on the paper. 4- Laser Printer (Non-Impact) – It uses technology of Photostat machine to print. 5- LCD or LED Printers (None Impact) – It is similar to laser printer but uses led or LCD in the place of Laser. 6- Line Printer – It woks same as Dot Matrix Printer but at fast speed. 7- Thermal Printer – It is very expensive type of printer and uses head and wax to print.

Dot Matrix Printer

The most popular kind of printer for small computers is the dot matrix printer, which forms characters as arrays of dots. Dot matrix printers are compact, reliable and relatively fast. This type of printer is an impact printer. The print head is the important hardware which produces the character

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COMPUTER HARDWARE

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using pins arranged in a matrix form. Normally a print head has 9 pins or 24 pins arranged in a matrix form. Combinations of pins strike an ink bed ribbon during the printing process. The print head moves in a line and the pattern of dots required for each character is printed on the paper. After printing a line, the paper rolls to print the next line. Dot matrix printers produce average quality prints and as generally used in business applications. They are used printing train number, seat number etc, on a railway reservation ticket. The speed of printing in dot matrix printer in dot matrix is measured in characters per second (cps).  The advantage in this type of printer is carbon copies can be obtained as printing takes place by physical impact with the paper. It is less of cost and easy to maintain.  The disadvantage is average printing quality and printer ribbon printer ribbon needs to be changed frequently.

Laser Printer
Laser printers are fastest type of non-impact electrostatic printers. They produce high quality prints at high speeds. It operates like a copier machine. In these printers, the controlled beam of intense laser forms images on an electrically charged rotating drum. The drum is rotated near the fine black powder called the toner. These charged images which sticks to the paper due to pressure and heat. The toner consists of oppositely charged ink particles which stick to the drum in the places where the laser has charged.

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COMPUTER HARDWARE

Amol Bajpai

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COMPUTER HARDWARE

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The light beam strikes a multi-sided rotating mirror. As the mirror rotates, the side currently in the path of the light beam sweeps the beam across the surface of the drum. As the beam sweeps across the drum, the light is modulated and a single line is drawn after a line has been drawn, the next side of the mirror is in place and a new line is drawn below the previous line. The quality of the printout is measured by the number of dots per inch (dpi). Since the dots are printed closely, the text or graphics appears very smooth and elegant. The speed is measured in number of pages printed per minute (PPM) which varies between 5 and 25.  The advantages are good quality printouts can be obtained for documentation and business applications. The printing is faster and easy to handle and maintain.  The disadvantages are the price is high and higher print cost.

Inkjet printer
An inkjet is a non-impact printer. It sprays tiny drops of ink to form character and graphic images on paper. The text and graphics printed in an inkjet printer are technically similar to that of a dot matrix printer. These types of printers can also be used color printing. The black inkjet printer uses black cartridge filled with black ink whereas the color printer uses four color cartridges namely cyan (blue), magenta (red), yellow, Green and black. These four colors are used in combination to generate any color in the visible spectrum.

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COMPUTER HARDWARE

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The print heads move across the page by the control of software and spray the dots of ink with the required combination of colors. The printer sends electrical pulses to thin resistors at the base of firing chambers behind the nozzle. A thin layer of ink is heated by the resistor which in turn forms a vapour bubble and the expansion forces ink through the nozzle and onto the paper at a rate of about 6000 dots per second. The quality of the printout is equivalent to that of laser printouts. The speed of printing is slower than that of laser printers.  The advantages of this type printer are the cost is low; quality of printing is equivalent to that of laser printing, color printouts are cheaper easy to handle and maintain.  The disadvantages are the ink cartridges may get spoiled if unused for a long time. Some inkjet printers are very expensive.

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COMPUTER HARDWARE

Amol Bajpai

Keyboard
Keyboard is a hardware which is used as a primary input device. The computer keyboard has the same key arrangement as the mechanical or electronic type written writer keyboard has other than text button the keyboard also contain standard function keys, tab and cursor keys, shift and controls key and some other manufacture customize keys.

Types of Keys on Keyboard

Types of keys on a computer keyboard:
Alphanumeric keys All of the letters and numbers on the keyboard. A-Z and 0-9. Punctuation keys All of the keys associated with punctuation such as the comma, period, semicolon, brackets, and parenthesis and so on. Also, all of the mathematical operators such as the plus sign, minus sign, and equal sign. Special keys All of the other keys on the computer keyboard such as the function keys, control keys, arrow keys, caps lock key, delete key, etc.

Special keys on a PC Keyboard
Alt key Short for Alternate, this key is like a second control key. Arrow Keys Most keyboards have four arrow keys that enable you to move the cursor (or insertion point) up, down, right, or left. Used in conjunction with the Shift or Alt keys, the arrow keys can move the cursor more than one position at a time, but this depends on which program is running.

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COMPUTER HARDWARE

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Backspace key Deletes the character just to the left of the cursor (or insertion point) and moves the cursor to that position. Caps Lock Key A toggle key that, when activated, causes all alphabetic characters to be uppercase. Ctrl key Short for Control, this key is used in conjunction with other keys to produce control characters. The meaning of each control character depends on which program is running. Delete Key Sometimes labeled Del, deletes the character at the current cursor position, or the selected object, but does not move the cursor. For graphics-based applications, the Delete key deleted the character to the right of the insertion point. Enter Key Used to enter commands or to move the cursor to the beginning of the next line. Sometimes labeled Return instead of Enter. Esc Key Short for Escape, this key is used to send special codes to devices and to exit (or escape) from programs and tasks. Function Keys Special keys labeled F1 to F12. These keys have different meaning depending on which program is running.

Form Factors of Keyboard
PC Keyboard – 83 Keys AT Keyboard – 101 Keys ATX Keyboard - 104 Keys

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Symbol Windows F1 - F12 Tab Caps lock Shift Ctrl Alt Back Space Delete Enter Prt Scrn Scroll lock Pause Break Insert Home Page up Page down Num Lock ~ ` ! @ # $ % ^ & * ( ) _ + = { } [ ] | \ / : ; " ' < > , . ? Explanation PC keyboards have a Windows key represented by a flag. Information about the F1 through F12 keyboard keys. Tab key Caps lock key Shift key Ctrl key Alt key (PC Only; Mac users have Option key) Back space key Delete or Del key Enter key Print screen key Scroll lock key Pause Break key Insert key Home key Page up or pgup key Page down or pgdn key Num Lock key Tilde Acute, Back quote, grave, grave accent, left quote, open quote, or a push Exclamation mark, Exclamation point, or Bang At or At symbol Octothorpe, Number, Pound, sharp, or Hash Dollar sign Percent Caret or Circumflex Ampersand, Epershand, or And Asterisk and sometimes referred to as star. Open parenthesis Close parenthesis Hyphen, Minus or Dash Underscore Plus Equals Open Brace, squiggly brackets, or curly bracket Close Brace, squiggly brackets, or curly bracket Open bracket Close bracket Pipe, Or, or Vertical bar Backslash or Reverse Solidus Forward slash, Solidus, Virgule, or Whack Colon Semicolon Quote, or Inverted commas Apostrophe or Single Quote Less Than or Angle brackets Greater Than or Angle brackets Comma Period, dot or Full Stop Question Mark

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Mouse
Mouse is an input device that is used to point to a place in the screen of your monitor and to select one or more action from that position. Types of Mouse1- Mechanical Mouse 2- Optomechanical Mouse 3- Optical Mouse Mechanical Mouse – Earlier type of mouse that has rubber or metal boll in it’s under side that can roll in or direction. Mechanical sincere within the mouse detects the direction the boll is rolling and move to screen pointer accordingly.

Optical Mouse – uses a laser to detect the mouse movement. We need to move the mouse on a special mat with grid. It is more precise and quick mechanical and optomechinical mouse.

Optomechinical Mouse- The optomechinical mouse consist of a ball which roles a wheal containing circuits of holes and notches to read the L.E.D. by a sensor as it spins around when the mouse is moved it is more accurate then mechanical mouse.

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PS2 Mouse USB Mouse

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Different type of connectors

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Modem
Modem is a networking device which is used to interface your computer with the wide area network (Internet). Its primary function is to convert analog signal into digital signals and digital signals into analog signals. The modem basically modulates or demodulates the data signals. The modulation is the process of conversion outgoing digital signal from a computer to analog signal.

Types of Modem – Internal Modem – Internal Modems are placed on the PCI slot inside the computer. You need to open the computer whenever you change or replace them.

External Modem – An external modem is used to a kind of interfaces connected to the computer such as USB. They are always placed as an external device and can be connected and disconnected easily.

Classification of Modem –
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1- Cable Modem- This modem used with coaxial cable television line providing a very fast access to the web up to the speed of 38 Mb (megabit) / sec. 2- DSL (Digital Subscribe Line) Modem – this type of modem is used for connection from a telephone to the user. This technology is divided into two main categories. A- ADSL (Asymmetrical Digital Subscriber Line Modem) – This line is used in North America and supports 1.5 Mb/sec to 9 Mb/sec download and 3 megabit / Sec upload transmission rate. B- SDSL (Symmetrical Digital Subscriber Line) Modem – used in Europe and as a same download stream and transmission upload rate 128 kbps.

2- ISDN (Integrated Services Digital Network) - ISDN is international communication standard for transmitting digital data over a telephone wire. The modem used with such phone lines. Other types of Modem USB MODEM

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SMPS (Switch Mode Power Supply)
SMPS is power supply which is used to provide pure DC to different component of the system another function of SMPS is to provide a device an adequate power supply to different working devices according to their requirement.

Type of SMPS
The type of SMPS basically depends on the type of function you are using according to different types of SMPS we have four categories. 1234AC in DC out DC in DC out AC in AC out DC in AC out

How SMPS works

Block diagram of main operated at DC SMPS with Output voltage regulation. 1- Input Rectifier filter – If SMPS has AC input, and then its first job is to convert input to DC. This is called Rectification. The rectifier provides an unrated voltage which is then send to a large filter capacitor. 2- Inverter stage- The inverter stage converts DC to AC by passing it through power oscillator. This process is shown in the block diagram as invertor chopper stage. 3- Voltage converter and output rectifier-The invented AC is used to pass through the voltage high frequency transformers to convert the voltage up or down according required output level as shown in output transforms in block diagram. Later on some more changes are done in output rectifier and filtering is done. The AC output form transformers is again rectifier i.e., converted from AC to DC. This rectified output is then smoothed by filters, consisting of conductors and capacitors. 4- Regulation – A feedback circuit monitors the output and compares it with a reference voltage, which is sets manually or electronically to the desired output. If there is any error in the output voltage the feed aback compensates by at by changing the input.

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Types of SMPS –
There are mainly three types of SMPS 1- AT (Advance Technology) SMPS (10 – 12 Pin) Power connector. 2- ATX SMPS ( 20 pins power connector) 3- MATX SMPS ( 24 Pins Power Connector) SMPS Power Connectors

20 Pins Power Connector

24 Pins Power Connector

The power supply is the most significant components of the computer. The power supply unit in a PC is called as Switch Mode Power Supply (SMPS).SMPS is used to convert 110V/220V Alternating Current (AC) into 3.3V, 5V, 12V Direct Current (DC) supply. The Integrated Chips (IC’s) like the motherboard operate with 3.3V or 5V DC voltage. The electro-mechanical components like the motor, fan operate at 12V DC power supply.

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20 Pins ATX Power Connector

24 Pins MATX Power Connector

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Display Adaptor
Display Adaptor is a part of computer which is used to produce output on the screen. The display adaptors are 8 bit, 16 bit and 32 bit.

Components of Display Adaptor
Graphic Processor The graphic processor chip is present on the graphic card. The graphic processor designed to carry out all the operations using hardware at the greater speed the by using software. Video Memory This part of display adaptor is used to store video images. Easier D Ram was used for video memory but due to the enhancement to the display image. To overcome this problem a separate video memory was installed on the display adaptor. VRAM (Video RAM) Ist type of memory used in display adaptor dedicated for graphic. WRAM (Windows RAM) Faster than V RAM EDO RAM More efficient the previous RAMs. SD RAM Similar to EDO but had common clock for memory and graphic chip to launch the data. SG RAM (Super Graphic RAM) It supports high performance graphic chip and offers enhanced fractures. Direct RD (Rambus Dynamic) RAM It is completely new memory architecture and offers performance 20 times faster than common D RAM. RAMDAC (Random Access Memory Digital to Analog) It is component present in display adaptor. It is needed to read content of the video memory and convert the digital information to analog signals and sends it’s over the video cable to the monitor signal stored in buffer to the voltage level suited for each color. Screen Resolution Screen resolution is the number of pixels that is used to create an image. It is expressed in width and light. E.g. 768x1024. It the screen resolutions is increased. It is necessary of care of the aspect ratio. The aspect ratio is the ratio between width to the highest of the image. Standard Type of for display adaptor Monochrome display adaptor (for Black & White Display) CGA - Color Graphic Adaptor HGA High Graphic Adaptor VGA Video Graphic Adaptor XVGA- Extended Video Graphic Adaptor SVGA – Super Video Graphic Adaptor

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Software
“Software is a collection of program which is used to perform specific task”

There are three type of Software

System Software - System software is computer software designed to operate and control the
computer hardware and to provide a platform for running application software System software has two types 1- Operating System – Operating system is software which acts as an interface between user and computer hardware. Examples: MS DOS , Windows 95 , Windows 98, Windows XP , Windows Vista , Windows 7 , Windows 8 , MacOS (For apple computers), Linux , UNIX.

2- System Utility – Mother Board drivers and device drivers

3- Application Software: Application software, also known as an application or an app, is computer software designed to help the user to perform specific tasks. Examples Microsoft Office, Tally, Photoshop, Nero, Adobe Reader, VLC media player etc.

Utility Software: Utility software is designed to help analyze, configure, optimize or maintain
Operating System. Utility software is usually called a utility or tool.

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Example: Antivirus Software (Norton Antivirus, Quick Heel Antivirus, Symantec Antivirus and Avast antivirus etc ), PC optimizer software.

Introduction to Operating System
An operating system is a software program that is as an interface between the user and the hardware of the computer. It also manages the resources of the computer such as memory, processor, input-output devices and files.

Functions of operating system
Some of the important functions of the operating system are explained in the following lines.  User Interface-the user interface of an operating system allows the user to interact computer. Operating system can have either or graphical user interface or both. In the character line interface with the user interacts with the computer using various commands. However a graphical user interface provides the user with a Windows-based environment that makes use of mouse, a keyboard, drop down menu, scrolling contains areas etc. Memory Management-The operating system manages memory management by allocating memory to the programs that are running and the allocating the memory when they are terminated. Process Management-The process management function of the operating system schedules the job to be executed and allocates the system resources needed by the particular task such as processor, memory, hardware. When the job is terminated the operating system release the system resource. Device Management-Operating system initiates the devices, sends or receives data from the devices and controls the operation of the device is such as printing, scanning, and if you. File Management - File management feature of the operating system refers to making the file system in terms of where the files are stored, their status and memory allocation. It also deals with the opening and closing the files, and providing access permissions to files. Further, the operating system determines the naming convention for files.

 

 

Classification of Operating System
The operating system can be classified based on the various parameters. Classification of operating system based on two categories the number of users and the number of task that can run simultaneously on computer. These two classifications are given below. Classification based on the number of users: Based on the number of users accessing the computer, the operating system can be classified into two types, namely single user and multi-user. These two categories are explained below: 1. Single User-In this type of operating system only one user can access the resources of the computer at time. Examples of single user operating system include this MS-DOS, Microsoft Windows. 2. Multi User-In this type of operating system more than one user can simultaneously access the computer resources. Examples of multiuser operating system including UNIX. VMS (Virtual Memory System) and Mainframe Operating System such as MVS (Multiple Virtual Storage), Linux & Novel NetWare etc.

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Classification based on the number of tasks Based on the task that can simultaneously on computer the operating system can be classified into two types, namely single tasking and multitasking. These are explained below: 1. Single Tasking - A single tasking operating system allows the user to perform a single task and time. Examples of single tasking operating system are MS-DOS, Palm OS for Palm handheld computers. 2. Multi-Tasking-A multitasking operating system allows the user to simultaneously execute multiple programs. Examples of multitasking operating system include Microsoft Windows, Linux, UNIX and Apple's Mac OS. An example of multitasking can be copying files from one drive to another and are running audio and video files simultaneously.

Microsoft Windows Operating System
Microsoft has introduced several version of Windows operating system starting from Windows version 1.0, Windows 8 of the present day. Each version of the operating system is an improvement over the previous version. Evolution of Microsoft windows Microsoft introduced the first version of Windows operating system named Windows 1.0 in year 1983. However the most popular Windows operating system and widely used by several user was Winters 3.0 which was released in 1990. Since Microsoft has released several versions of Windows operating system the latest is the Windows 7 operating system. The various desktop versions of Windows operating system and there are features 1. Windows 3.0 release in 1990 It offered improved performance, advanced graphics with 16 colors, and is full support of a more powerful and Intel 386 processor. Some of the important features of this version were an all Windows operating systems are listed below:  Program manager, file manager and print management.  A completely rewritten application development environment  An improvement set of Windows icon

2. Windows NT 3.1 released in 1993 Windows NT (New Technology) was a 32-bit operating system and was the first Windows operating system to combine support for high-end, client/server business applications with the industry is leading personal productivity applications. It was initially available in both a desktop (workstation) was in

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and server version called Windows NT advanced server. It was secure, stable and had a Microsoft Win32 application programming interface (API). Some of the important features of this version of Windows operating system are listed below:  Preemptive multitasking schedule for Windows-based applications.  Integrated networking  Domain server security  OS/2 and POSIX subsystem  Support for multiple processor architectures  NTFS(New Technology File system) file system 3. Windows for Workgroup 3.11 released in 1993 This version of Windows operating system added support for peer-to-peer workgroup and domain networking. Windows for workgroups can be used in both local area networks (LANs) and on standalone PCs and laptop computers. Some of the important features added to the operating system are:  centralized configuration and security  Improved support for Novel NetWare networks  Remote access service

4. Windows NT for workstation 3.5 released in 1994 This version of Windows operating system provided high degree of protection yet for critical business application and data. Some of the important features of this version are:  Support for openGL graphical standard.  Provided support for Novell NetWare file and print servers.  Allowed for use for long filename up to 255 characters. 5. Windows 95 released in 1995 This version of Windows operating system integrates a 32-bit TCP/IP (Transmission Control Protocol/Internet Protocol) stuck for built-in Internet support for dial-up networking. Other features include:  Plug and play capabilities that are made it easy for users to install hardware and software.  Enhanced the multimedia capabilities.  More powerful features for mobile computing and integrated networking.

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6. Windows NT Workstation 4.0 release in 1996 This version of the Windows operating system provided improved and networking support for easier and more secure access to the Internet and corporate intranets.

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7. Windows 98 released in 1998 This version of Windows operating system is an upgraded form of Windows 95. It included the ability to open and close applications more quickly, support for reading DVD discs, and the support for a universal serial bus (USB) devices. 8. Windows 98 second edition released in 1999 This version of Windows operating system is an incremental update of Windows 98 and was the first operating system that supports device like Windows NT. Some of the important features of this version are:  Provides compatibility for a new and inherent hardware and Internet related features.  It included features such as Internet explorer 5.0 browser technologies, Microsoft Windows NetMeeting 3.0 conferencing software.  It also included Microsoft direct X API 6.1, which provided improved support for windows multimedia.  Provides home networking capabilities through Internet connection sharing (ICS). 9. Windows Millennium Edition (Windows Me), released in 2000 This version of the Windows operating system is designed for home computer users. It offers consumers numerous music, and video and home networking enhancements and reliability improvements. It was the last Microsoft operating system which was based on the Windows 95 code base.

10. Windows 2000 professional released in 2000 This version of operating system was designed to replace Windows 95, 98 and Windows NT workstation 4.0. Major improvements include reliability, ease of use, Internet capability, and his support for mobile computing. Additionally, it simplified hardware installation by adding support for a wide variety of new plug and play hardware, including advanced networking and wireless products, USB devices, IEEE 1394 devices, and infrared devices.

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11. Windows XP professional released in 2001 The XP in Microsoft windows stand for “experience” and symbolized the innovative experiences that Windows offers to personal computer users. In Microsoft windows XP pro professional operating system home user can work with and enjoy music, movies, messaging, and photos with their computer, while business users can work smarter and faster. Other features include:  It provides a flash Visual in design.  Includes Remote Desktop support and advance networking features.  Provides encrypting file system, and system restore.  It includes wireless 802.1 X networking support, Windows messenger, and remote assistance feature for mobile users. Editions of Microsoft Windows XP  Windows XP Home Edition  Windows XP Professional Edition ( Service Pack 1,2,3)(Also available in 64 bit editions)  Windows XP Tablet PC Edition  Windows XP Starter Edition

Hardware requirement of Windows XP System Requirements

System requirements for Windows XP Home Edition and Professional are as follows.
Minimum Processor Memory Video adapter and monitor Hard drive disk free space Recommended

Optical drive Input devices Sound Physical memory limits

233 MHz At least 300 MHz 64 MB of RAM At least 128 MB of RAM Super VGA (800 x 600) or higher resolution 1.5 GB or higher (additional 1.8 GB for Service Pack 2 and additional 900 MB for Service Pack 3 CD-ROM drive (Only to install from CD-ROM media) Keyboard, Microsoft Mouse or a compatible pointing device Sound card, Speakers or headphones

Maximum limits on physical memory (RAM) that Windows XP can address vary depending on both the Windows version and between 32-bit and 64-bit versions. The following table specifies the maximum physical memory limits supported:

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Physical memory limits for Windows XP versions
Version Limit in 32-bit Windows Limit in 64-bit Windows Windows XP Professional 4 GB 128 GB N/A Windows XP Home Edition Windows XP Media Center Edition Windows XP Tablet PC Edition Windows XP Starter Edition 512 MB 12. Windows Server 2003, released in 2003 Just like Windows 2000 server which had a “family” of server operating system, Microsoft include Windows server thousand three in four protect addition. Microsoft introduced new features over the 2003 server but all of them are not available in four editions. They are listed here:  Windows server 2003, Standard addition  Windows server 2003, Enterprise edition (32 bit and 64-bit versions)  Windows server 2003, Data Center edition(32 bit and 64-bit versions)  Windows server 2003, Web Edition There are a whole lot's of new features associated with the Microsoft server 2003 but the most interesting would be the fact that is available in 32 bit, 64 bit, and embedded versions. The 64 bit versions are available on those server computers that utilize Intel's Pentium processor or other compatible processors. Device Processor RAM HDD Display Adapter Optical Device Minimum Pentium 450 MHZ 128 MB 2 GB VGA CD ROM Recommended Pentium 2 256 MB 4 GB SVGA CD ROM Best perform Better 512 MB Better Better CD ROM

13. Windows Vista, released in 2005 Windows Vista provides a solid visual experience. You can see what your files contained without opening them, find applications and files instantly, navigate efficiently among open windows. Some of the important features of Windows Vista operating system are as follows:  A built-in diagnostic code activity detects problems with system components.  Windows vista uses Internet protocol version 6.  Internet Explorer Version 7.0 is introduced.

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Hardware requirements Computers capable of running Windows Vista are classified as Vista Capable and Vista Premium Ready. [61] A Vista Capable or equivalent PC is capable of running all editions of Windows Vista although some of the special features and high-end graphics options may require additional or more advanced hardware. A Vista Premium Ready PC can take advantage of Vista's high-end features. Windows Vista system requirements Vista Capable Processor 800 MHz Memory 512 MB Graphics card DirectX 9.0 capable Vista Premium Ready 1 GHz 1 GB DirectX 9.0 capable and WDDM (Windows Display Driver Model ) 1.0 driver support 128 MB 40 GB

Graphics memory HDD capacity HDD free space Optical drives

32 MB 20 GB 15 GB DVD-ROM drive (Only to install from DVD-ROM media)

Physical memory limits
Maximum limits on physical memory (RAM) that Windows Vista can address vary depending on the both the Windows version and between 32-bit and 64-bit versions. The following table specifies the maximum physical memory limits supported: Physical memory limits for Windows Vista versions Version Limit in 32-bit Windows Limit in 64-bit Windows Windows Vista Ultimate 4 GB 128 GB Windows Vista Enterprise Windows Vista Business Windows Vista Home Premium 16GB Windows Vista Home Basic 8GB Windows Vista Starter 1 GB N/A Processor limits The total maximum number of logical processors in a PC that Windows Vista supports is: 32 for 32bit; 64 for 64-bit. The maximum number of physical processors in a PC that Windows Vista supports is: 2 for Business, Enterprise, and Ultimate; 1 for Starter, Home Basic, and Home Premium. 14. Windows 7 Released In 2009 Windows 7 is the current release of Microsoft Windows, a series of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, notebooks, tablet PCs. Windows 7 was released to manufacturing on July 22, 2009, and reached general retail availability worldwide on October 22, 2009,

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less than three years after the release of its predecessor, Windows Vista.

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Minimum hardware requirements for Windows 7
Architecture
Processor Memory (RAM) Graphics card HDD free space Optical drive Physical memory limits

32-bit

64-bit

1 GHz processor 1 GHz x64 processor 512 MB 2 GB DirectX 9 graphics (SVGA) 16 GB of free disk space 20 GB of free disk space DVD-ROM drive (Only to install from DVD-ROM media)

Maximum limits on physical memory (RAM) that Windows 7 can address vary depending on both the Windows version and between 32-bit and 64-bit versions. The following table specifies the maximum physical memory limits supported:

Physical memory limits for Windows 7 versions
Version Limit in 32-bit Windows Limit in 64-bit Windows Windows 7 Ultimate 4 GB 192 GB Windows 7 Enterprise Windows 7 Professional Windows 7 Home Premium 16 GB Windows 7 Home Basic 8 GB N/A Windows 7 Starter 2 GB

Microsoft Windows Upgrade chart

Windows client operating system Windows 98 Windows ME Windows NT workstation 4.0 Windows 2000 professional Windows 95 Windows NT 3.1, 3.5, or 3.51

Upgrade to Windows XP professional Windows XP professional Windows XP professional Windows XP professional Windows 98 first and then upgrade to Windows XP professional Windows NT workstation first and then to windows XP professional

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File systems
A file system is a method of storing and organizing the data in order to easily locate and access the files from the storage device such as hard disk, floppy desk on CD-ROM. File system creates a directory structure which operates the partition into smaller files, a sign names to each file, and manage the free space available to create new files. Windows operating system uses a tool created format to create the different types of file system. Some of the important file systems supported by Windows operating system are fat 16, fat 32, NTFS 4.0, NTFS 5.0. The following table summarizes the file system supported by various Windows operating system:

Types of File system
1- Fat 16 (File Allocation Table) – It uses 16 bit binary number to store the data on hard disk. Fat 16 systems can recognize storage space up to 2 GB. 2- Fat 32 – It uses 32 bit binary number that stores data on the hard disk. It supports up to 2TB storage space. 3- NTFS (New Technology File System) – It is the high level file system that Insures high level security along with file storage. It insures that file does not get corrupted while saving due to any failure or technical problem.

File Attributes supported by FAT
1234123456R – Read Only A – Archive S – System H – Hidden R – Read Only A – Archive S – System H – Hidden Compress Encrypt
Operating system Windows NT 4.0 Windows 95 Windows 98 Windows ME Windows 2000 Windows XP Windows 2003 Windows Vista Windows 7 Fat 16 Yes Yes Yes Yes Yes Yes Yes Yes Yes Fat 32 Yes Yes Yes Yes Yes Yes Yes Yes NTFS 4 Yes NTFS 5

File Attributes supported by NTFS

Yes Yes Yes Yes Yes

System Files
System files specific of Windows 9X (Windows 95, Windows 98, Windows ME) Operating System
1- MSDOS.sys - This file handles disk input and output. It is loaded into memory and stays there. 2- EMM386.EXE - This file is used to view UMBs (upper memory blocks) 3- Himem.sys -This file is automatically executed during start-up for accessing upper memory. 4- IO.sys - This file manages the input and output routines of the computer, allows the rest of the operating system and the program to interact directly with the systems hardware and the system’s bios. 5- Win.ini - This file is used for the Windows environment. This file is now replaced with a registry. 6- Win.com - This file is the Windows start-up program that tests the system function and prepares the Windows environment. 7- System.ini - This file contains drivers for windows devices. 8- Command.com – This file is the command interpreter. It displays command line interface for to use DOS commands.

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9- Config.sys – This file consists of commands that are executed after the Windows operating system boots up. The commands present in the file are executed before the commands present in the Autoexec.bat file. This file consists of commands that are essential for setting up a constant computing environment, for example device drivers. This 10- Autoexec.bat - This file contains of commands that are automatically executed when system is starts. It consists of commands to load the hardware such as mouse, keyboard, and network software. This file also consists of commands that are used to set prompt search part and other system variables.

System File is specific to Windows NT (Windows 2000, Windows 2000 Server, Windows NT, Windows XP, Windows 2003) Operating System
1- Ntldr - This file is used to load the operating system. It is also referred to as a bootstrap. 2- Boot.ini - This file is stores the location of the operating system. 3- Bootsect.dos -This is used to configure the Boot configuration and allow the PC to boot Win9x by keeping your copy of their boot sectors. 4- Ntdetect.com - This file is used to create dynamic hardware information in the registry. 5- Ntbootdd.sys - This file is used when a SCSI hard disk is used as a boot device. 6- Other files – win.com and hal.dll file are required upon booting.

Boot sequence in Windows Operating System
The boot sequence in Windows operating system consists of the following steps:       POST performs a check on all hardware components. Master Boot record (MBR) loads into memory. IO.sys loads into memory and loads a registry into memory. Also starts CPU in real mode. Win.com loads and transfers the CPU to protected mode. Windows kernel and virtual device driver are loaded. Explorer.exe loads to display the GUI (Windows interface).

Alternative boot methods
When the computer doesn't starts, you need to press the F8 key to boot the computer using alternate methods. These are listed below:  Boot to safe mode - This starts the operating system with the minimum files and drivers.  Boot to safe mode with networking- Same as safe mode, but loads networking components too.  Boot to safe mode with the command promptLoads into safe mode but goes directly to a command prompt.  Enabling to boot logging - Saves boot information to a Ntbtlog.txt file under the Windows directory to be used for diagnosing start-up problems.  Enable VGA mode-Used to fix and incorrect video driver.  Last known good consideration - To restore system to last known backup state by replacing the registry.

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Computer Viruses
Computer virus is a software program written with malicious intentions. There are number of computer viruses that can impede the functioning of your computer system. Let us see what are the different types of computer viruses. Computer Virus is a malicious software program written intentionally to enter a computer without the user's permission or knowledge. It has the ability to replicate itself, thus continues to spread. Some viruses do little but replicate, while others can cause severe harm or adversely affect program and performance of the system. A virus should never be assumed harmless and left on a system. Most common types of viruses are mentioned below:

123-

File Infector Virus Boot Record Infector Macro Virus

There are different types of computer viruses which can be classified according to their origin, techniques, types of files they infect, where they hide, the kind of damage they cause, the type of operating system or platform they attack etc. Let us have a look at few of them.

Resident Virus
This type of virus is a permanent as it dwells in the RAM. From there it can overcome and interrupt all the operations executed by the system. It can corrupt files and programs that are opened, closed, copied, renamed etc. Examples: Randex, CMJ, Meve, and MrKlunky.

Direct Action Viruses
The main purpose of this virus is to replicate and take action when it is executed. When a specific condition is met, the virus will go into action and infect files in the directory or folder that it is in as well as directories that are specified in the AUTOEXEC.BAT file path. This batch file is always located in the root directory of the hard disk and carries out certain operations when the computer is booted. Examples: Vienna virus.

Overwrite Viruses
Virus of this kind is characterized by the fact that it deletes the information contained in the files that it infects, rendering them partially or totally useless once they have been infected. The only way to clean a file infected by an overwrite virus is to delete the file completely, thus losing the original content. Examples: Way, Trj.Reboot, Trivial.88.D.

Boot Sector Virus
This type of virus affects the boot sector of a floppy or hard disk. This is a crucial part of a disk, in which information of the disk itself is stored along with a program that makes it possible to boot (start) the computer from the disk. The best way of avoiding boot sector viruses is to ensure that floppy disks are write-protected and never starting your computer with an unknown floppy disk in the disk drive. Examples: Polyboot.B, AntiEXE.

Macro Virus
Macro viruses infect files that are created using certain applications or programs that contain macros. These mini-programs make it possible to automate series of operations so that they are performed as a single action, thereby saving the user from having to carry them out one by one. Examples: Relax, Melissa.A, Bablas, O97M/Y2K.

Directory Virus
Directory viruses change the path that indicate the location of a file. When you execute a program file with an extension .EXE or .COM that has been infected by a virus, you are unknowingly running the virus program, while the original file and program is previously moved by the virus. Once infected it becomes impossible to locate the original files. Examples: Dir-2 virus.

Polymorphic Virus
Polymorphic viruses encrypt or encode themselves in a different way (using different algorithms and encryption keys) every time they infect a system. This makes it impossible for anti-viruses to find them using string or signature searches (because they are different in each encryption). The virus then goes on creating a large number of copies. Examples: Elkern, Marburg, Satan Bug and Tuareg.

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File Infector Virus
This type of virus infects programs or executable files (files with .EXE or .COM extension). When one of these programs is run, directly or indirectly, the virus is activated, producing the damaging effects it is programmed to carry out. The majority of existing viruses belong to this category, and can be classified depending on the actions that they carry out. Examples: Cleevix and Cascade.

Companion Viruses
Companion viruses can be considered as a type of file infector viruses like resident or direct action types. They are known as companion viruses because once they get into the system they 'accompany' the other files that already exist. In other words, in order to carry out their infection routines, companion viruses can wait in memory until a program is run (resident virus) or act immediately by making copies of themselves (direct action virus). Some examples include: Stator, Asimov.1539 and Terrax.1069

FAT Virus
The file allocation table or FAT is the part of a disk used to store all the information about the location of files, available space, unusable space etc. FAT virus attacks the FAT section and may damage crucial information. It can be especially dangerous as it prevents access to certain sections of the disk where important files are stored. Damage caused can result in information losses from individual files or even entire directories.

Multipartite Virus
These viruses spread in multiple ways possible. It may vary in its action depending upon the operating system installed and the presence of certain files. Examples: Invader, Flip and Tequila

Web Scripting Virus
Many web pages include complex code in order to create an interesting and interactive content. This code is often exploited to bring about certain undesirable actions.

Worms
A worm is a program very similar to a virus; it has the ability to self-replicate and can lead to negative effects on your system. But they can be detected and eliminated by anti-viruses. Examples of worms include: PSWBugbear.B, Lovgate.F, Trile.C, Sobig.D, Mapson.

Trojans or Trojan Horses
Another unsavory breed of malicious code are Trojans or Trojan horses, which unlike viruses do not reproduce by infecting other files, nor do they self-replicate like worms. In fact, it is program which disguises itself as a useful program or application.

Logic Bombs
They are not considered viruses because they do not replicate. They are not even programs in their own right but rather camouflaged segments of other programs. They are only executed when a certain predefined condition is met. Their objective is to destroy data on the computer once certain conditions have been met. Logic bombs go undetected until launched and the results can be destructive. Besides, there are many other computer viruses that have a potential to infect your digital data. Hence, it is a must that you protect your data by installing genuine quality anti-virus software. What do Viruses do?

   

Can damage files Can slow system Can show messages Can take control

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COMPUTER HARDWARE

Amol Bajpai

Troubleshooting the PC using Beep Codes
Indicator 1 Beep System Status DRAM refresh failure Parity Circuit Failure Base 64K RAM failure Explanation A problem is encountered when accessing the system memory to refresh it The parity circuitry is not working Diagnosis Issue is with the system memory or the motherboard Problem with either the system memory or the motherboard A bad memory chop could be three in the first bank of memory or the failure could be due to the motherboard or system device Failure of the motherboard Recommendation  Reseat memory  Place the RAM in another slot  If is still does not work, replace the RAM  Reseat memory  Place the RAM in another slot  If still does not work, replace the RAM  Reseat memory  Place the RAM in another slot  If it still does not work, replace the Ram

2 Beeps

3 Beeps

A failure has occurred in the first 64 KB of system memory

4 Beeps

Motherboard Timer Failure Processor Failure

5 Beeps

One or more timers that control the motherboard functions might not be working Problem with the processor

 Repair/Replace motherboard

The processor is not dead, otherwise it would not have booted at all A problem with either the motherboard or the keyboard

6 Beeps

Keyboard controller/ gate A20 Failure

7 Beeps

8 Beeps

Virtual mode exception error Display memory read /write failure

A failure with either the keyboard controller ( a chip on the motherboard the communicates with the keyboard) or the A20 gate that is controlled by the keyboard controlled The system when listing the virtual mode encounters an error Happens when the BIOS cannot write to the frame buffer memory on the video card (a non-fatal error) A mismatch has occurred when the checksum value (that verifies if the ROM code is right) is compared with the values in the ROM An error caused when a component in the motherboard interacts with the COMS memory that holds the BIOS settings An error occurred when the system was verifying the operation of the secondary (level 2) cache Constant beeping in no specific pattern

 Troubleshoot the Processor by trying it on another motherboard  If there is no problem with the processor, repair/ replace motherboard  Check the keyboard connections  Replace the keyboard  if the error still persists, repair the motherboard as the keyboard controller chip could be at fault  Repair/replace motherboard

Issue with either the processor or the motherboard Issue with either the video card or its memory card. A motherboard problem can cause this issue as well. The BIOS ROM chip on the motherboard could not be functioning properly

9 Beeps

ROM BIOS checksum failure

10 Beeps

11 Beeps

CMOS shutdown register read / write error Cache memory error Memory or video problem

Problem with the COMS battery

 Place the video card onto another PCI slot  If the error persists, replace the video card  Repair the motherboard  If the BIOS ROM is removable, reseat it  Replace the BIOS chip with the exact same version of the faulty chip  If the error persists, repair or replace the motherboard  Replace the COMS battery  If the error persists, repair motherboard  Repair/replace motherboard

A problem with the system cache or the motherboard

Continuous Beeps

Mostly an error with system memory

 Troubleshoot the system memory  Trouble shoot the video card  If the error persists, repair/ replace the motherboard

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COMPUTER HARDWARE

Amol Bajpai

Page 85

COMPUTER HARDWARE

Amol Bajpai

Page 86

COMPUTER HARDWARE

Amol Bajpai

नोट: रातों-रातो कोई भी स्वदे शी वस्तोु ववदे शी हो सकतोी है और कोई भी ववदे शी वस्तोु स्वदे शी हो सकतोी है । भारतो क े बाजार मं वैश्वीकरण की प्रक्रिया क े बाद बहुतो सारे ब्राण्ड वस्तोुएॊ स्वदे शी से ववदे शी हो जातोी हं । कृ पया आप अपने स्तोर से अखबारं एवॊ पविकाओॊ क े माध्यम से इस सन्दभभ मं जानकारी तोाजा करं । ननवेदन - आप जहाॉ भी रहतोे है । उसक े आस-पास सैकड़ों स्वदे शी वस्तोुएॊ बनतोी हं कृ पया आप इनक े बारे मं जानकारी करं और उन स्वदे शी वस्तोुओॊ का अनिक से अनिक उपयोग एवॊ प्रचार करं ।

स्वदे शी अपनाये, भारतो सम्रद्ध बनाए अमोऱ बाजपेई

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