CHAPTER - 1 (FULL)

CHAPTER-1

CONFIGURING A COMPUTER

1.2   REVIEW OF THE BLOCK DIAGRAM OF A COMPUTER:

            A  Computer is designed using four basic units. They are:

1.       Input data

2.      Central processing  unit (CPU)

a.        Control unit

b.      Arithmetic and logic unit

3.      Memory  unit

4.      Out put unit

1.       Input unit: 

i)The Input unit basically links the external world or environment to the computer system. .

ii)The keyboard and mouse of a computer are the most commonly used input devices.

2.      Central processing unit (CPU):

i)To interpret the instructions in the program and execute them one by one.

The units are,.

a)      Control unit: Transfers the program instructions and data between various units.

b)      Arithmetic and logic unit (ALU): Arithmetic operations like (+, -,*,^,/), logical operations like(AND, OR, NOT) and relational operations like (<, >,<=,>=) are performed  in this  unit.

c)      Registers: To store the intermediate data.

3.      Memory unit: To store input , intermediate results and the output.

4.      Output data: To print or to display the results.

1.3 GENERAL STRUCTURE OF A CPU:

                       

i.        Program counter: To keep track of the memory address of next instruction which has to be executed.

ii.       Memory address register: i) specifies the address to memory where information can be found  ii)To point to a memory location where information is to be stored.

iii.      Memory data register / Memory buffer register: An interface between the central processing unit and memory.

iv.     Instruction register (IR): The instruction register holds the instruction until it can be decoded.

v.      Timing and control unit (TCU):i) The operations of the CPU should always be performed in a proper sequence.

ii)The timing and control unit is used to generate all internal and external control signals which carries the execution.

vi.    Instruction decoder (ID): i)An electronic hard ware which decodes the instruction .

ii)The instructions are further broken down into a set of micro operations so that they can be executed directly.

vii.  Arithmetic logic unit (ALU):  i)performs arithmetic, logical and relational operations.

ii)Results will be transferred back to the accumulator.

viii.     Accumulator (ACC): To store the initial, the intermediate and the final result of an instruction.

1.4 HOW INSTRUCITON IS EXECUTED?

            A basic instruction execution cycle can be broken down into the following steps:

1.       Instruction cycle

2.       Execution cycle

1.      Instruction cycle:

a.      Instruction Fetch

i)Program Counter holds the memory address of next instruction.

ii)Address transferred to Memory Address Register.

iii)Data transferred to Memory Data register based on CPU’s read request.

iv)Data transferred to Instruction Register.

v)Program Counter incremented to point out address of next data.

b.      Instruction decode:

i)Determines the type of instruction.

ii)Selecting signals accordingly.

2.      Execution cycle: i)Data will be processed by CPU and get stored in accumulator temporarily. ii)Then transferred to the main memory.

1.5 FACTORS AFFECTING THE PROCESSING SPEED

             

i.        Register size : i)Normally the register size in the processor will be of 32 bits.

ii)Smaller size  will reduce the speed.

ii.      Memory size: i)The  amount of RAM or main memory can also affect the speed.

ii)The size of the RAM may vary from 64 megabytes to 4 gigabytes.

iii.    Clock speed: i)The computers system clock sets the pace for the CPU by using a vibrating quartz crystal.

ii)Fast clock  can process more instructions.

. For example 1000MHZ processor performs 1000 million instructions per second.

iv.    Data bus capacity : i)The width of the data bus determines how many bits can be transmitted at a time between the CPU and other devices.

ii)width of the address bus give the amount of address space, which can be accessed at any instance of time.

v.       Cache memory  : i) A  high speed memory that contains the most recent data.

ii)  The cache memory  normally varies 512KB to 1MB.

iii)The more the cache the execution speed will be faster.

vi.    Instruction set: i)The set of basic commands the processor can understand and execute is called the instruction set.

ii)More the number of bits in a processor, the larger the instruction set.

For example, a 16- bit processor has larger instruction set than 8-bit processor.

vii.  Heat and heat dissipation: i)When the processor runs it generates heat and becomes too hot. ii)Installing an adequate cooling system is the solution

1.6 EVOLUTION OF MICROPROCESSOR:

            i)Microprocessor is an integrated circuit on a single chip.

           ii)Single micro processor is equivalent to mainframe computers.

          iii)Some microprocessor companies are Intel, Motorola, Advanced  Micro Devices (AMD), and             Cyrix..

    iv)Intel Corporation is the largest manufacturer of microchips in the world.

         Manufactured Year with the model.

Model                           Year

4004                                1971

8008                              1972

8080                                1974

8086                               1978

80286-80486                 1982 - 1989

Pentium 1 – Pentium 4 1993-2000

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1.7.1 ,MOTHER BOARD

1.7.1.1  Define Motherboard.

              The main circuit board of the computer which contains the CPU, memory, expansion slots, bus,              and video controller. Also called as system board.

Specify The Components of Motherboard.

1.7.2.1 BUS :  i)a set of electrical conducting lines, through which binary information is transferred.

ii)Types are, internal and External.

iii)The internal bus can be connects the different components inside the case: The CPU, system memory, and all other components on the mother board. Also called as system bus.

iv)The external bus connects the different external devices, peripherals expansion slots, I-O ports and drive connections to the rest of the computer.

1.7.2.2 Communication of ports or I-O   ports:

            Port :  A   socket on the back of the computer used to connect external devices to the computer.

a)      Serial ports :

i)Devices like  mouse, modem, older printers can be attached.

ii)Transfers data serially one bit at a time.

iii)Are also called as RS-232-C  ports or COM  ports.

b)      Parallel    ports

i)Devices like printers and some types of external storage devices can be attached.

ii) Transfers data on parallel path with 8 bits at a time.

iii)Are also called as the printer port, or LPT1 .

          c)  SCSI(small computer system interface)port

i)Devices like hard disks ,high end scanners and CD-ROM drives can be attached.

ii)Transfers data fastly.

          d)  USB (universal Serial Bus)

i)Devices like audio players, joysticks, keyboards, modems, scanners, and printers with USB

can be attached.

ii)a plug and play interface to attach add-on devices.

iii)devices can be added without adding an adapter card or restarting the system.

d)      Game Port

i)Gaming devices like joysticks  can be attached.

ii)Provides for more intense gaming actions.

1.7.2.3 MOTHERBOARD SLOT OR EXPANSION SLOT

            Explanation slot:

           i)The area of the motherboard into which expansion boards are inserted.

ii) An ISA (industrial standard architecture) slot is a 16 bit slot. A PCI slot is 32 bits.  The AGP (accelerated graphics port) slot is for inserting graphics card which make graphics application run faster.

1.7.2.4 Input device ports

            i)All PCs have a keyboard   port connected directly to the mother board.

          ii)Keyboard and mouse are connected with ps/2 connector.

1.7.2.5 RAM slots:

           i) Random Access Memory stores  programs and data currently being by the CPU.

           ii)Types of sockets to install the memory are SIMM(Single inline memory module) sockets and DIMM(Dual inline memory module) sockets.

1.7.2.6 Hard disk controller:

           i) A controller is a device that is responsible for controlling data flow.

           ii)Hard  drive controller is responsible for the following,

1.       Receiving information from the processor and converting or interpreting the information into signals that the hard disk can understand.

2.      Sending information back to the processor and converting the information into signals that the processor can understand.

            iii)The first major standard developed for hard disk controllers is the IDE(integrated digital electronics) standard.

1.7.2.7 : Floppy disk controller :

               Connects the floppy drive to the mother board.

1.7.2.8  Processor slot

                        The processor is usually the largest chip on the system board.

1.7.2.9  Cache memory :

i)Cache memory increases performance by storing frequently used data.

ii)It is faster than RAM.

iii)Types are,

    L1(level-1) cache : cache that is integrated within the processor.

    L2 (level-2) cache: cache that is located outside the processor, like on the mother board.

1.7.2.10 BIOS chip

i)The basic  input output system (BIOS) is low level program code that allows all the system devices to communicate with one another.

ii)Has code which controls the boot process of the system.

iii)Has code which performs  power on self test(POST).

iv)Calls on the master boot record which will load an operating system.

1.7.2.11 CMOS battery

i)Complementary metal oxide semiconductor (CMOS).

ii)CMOS is a listing of system components, such as the size of the hard disk , the amount of RAM, and the resources used by the serial  and parallel ports.

iii)CMOS RAM should not lose its charge. If so, its content will be lost.

1.8 PRINTERS

                  An output device that produces text and graphics on a physical medium.

1.      Quality type : Letter quality or draft quality.

2.      Speed : Characters  per second (CPS) or pages per minute (PPM),

3.      ‘impact or non impact :Impact printer is dot-matrix printer(striking ink ribbon).

Non-impact printers are ink-jet printers and laser printers(non striking mechanism).

4.      Graphics : Some printers can print only  text. Other printers can   print both text and graphics.

5.      Fonts : Some  printers, notably dot matrix printers, are limited to one or a  few fonts.

Laser  and ink-jet printers are capable of printing an almost unlimited variety of fonts

1.8.1 specifications of some   printers :

PRINTER	PRINTING SPEED	BUFFER SIZE
DOT MATRIX	30-300CPS	1K-64K
INK-JET	1-12PPM	1MB-4MB
LASER	4-24PPM	4MB-32MB

Line printer : This type of  printer contains a chain of characters or pins that  print an entire line at one time.

           Thermal printer : pushing heated  pins against heat-sensitive paper.

           Widely used in  calculators and fax machines.

1.9 KEYBOARD

            i)Key boards are designed to input text and characters.

          ii)An arrangement of rectangular buttons.

          iii)Characters printed on the keys.

          iv)Types of keys are alphabet,numerical,special and functional.

          v)Multimedia and internet keyboards are available.

1.10 MOUSE

            Controls the movement of cursor or pointer on a display screen.

1.      Mechanical : i)Has a rubber or metal ball on its underside that can roll in all directions. Ii)Mechanical sensors within the mouse detect the directions and move the cursor.

2.      Opto-mechanical: Uses optical sensors to detect  motion of the ball.

3.      Optical: i)Uses a laser to detect the mousers movement  

ii)They respond more quickly.

Mouse can be connected to the compute in one of the following ways :

1.      Serial mouse: They are connected directly to an RS-232C serial port or a PS/2 port.

2.      PS/2 mouse:  They are connected to a PS/2 port.

3.      USB mouse: They are connected through USB port.

4.      Cordless mouse: i) No physical connection.

ii)Instead they rely on infrared or radio waves to communicate with the computer.

1.11 MONITOR OR VIDEO DISPLAY UNIT (VDU)

            Monitors provide a visual display of data.

1.      Monochrome: i)Display two colors. One for the back ground and one for the foreground. ii)Colors can be black and white or Green and black.

2.      Colors: i) Display 1 million colors

Characteristics/Features of a monitor

1.       Refresh data: i)How many times per second the screen is refreshed.

ii) To avoid flickering, the refresh rate should be at least 72 Hz.

2.      Interlaced or non interlaced: Resolution Rate

3.      Convergence: The clarity and sharpness

1.12     RANDOM ACCESS MEMORY

             i)To store the data while using.

           ii)Volatile memory.

           iii)Constant current is required to retain the information.

1.12.1  Types of RAM

1. Static RAM:     i)Has multiple transistors for each memory cell.

                            ii)Need not be refreshed.

            2. Dynamic RAM: Need to be refreshed.

            3.  SDRAM:          i)Synchronous Dynamic Random Access memory.

        ii)Synchronized to the system clock.

        iii)Has the ready-data  when the CPU requests it.

        iv)Increases the efficiency by reducing CPU waiting time.

            4.DDR-RAM:         i)Double Data Rate SDRAM.

     ii)Data transfer rate is double

1.13 SECONDAAARY OR AUXILIARY STORAGE DEVICES:

1.13.1  Floppy disk drive (FDD): i)To record the data.

                                                 ii)Sizes are 8’’, 5.25”,   and 3.5”

                                                 iii)Can store approximately 1 million characters.

1.13.2 Compact Disk : i)An  optical disc  used  to store  digital data.

                                  ii)Types are CD-R and CD-RW.

                                  iii)Can store approximately 700 MB of data

DVD (digital versatile disc or digital video disc :

              Can store approximately 4.7 GB of  data

A Blu -Ray Disc(BD)

               i)A single layer blu-ray Disc can store 25 gigabytes(GB).

               ii) A dual layer blu-ray Disc can store 50 GB.

1.13.3 Hard Disk Drive (HDD) :

            i)A maximum storage 20 GB – 250 GB.

          ii) Rotational speed is 7200 rpm 

          iii)Types are,.

1.      Small Computer System Interface(SCSI) HDD : For high end users or servers.

2.      Integrated Disk Electronics (IDE)HDD :  Standard in today’s computer.

3.      SERIAL ATA (SATA) :  i)Have large capacity. ii)Have fast transfer rates.

4.      EXTERNAL HDD : Backup disk.

1.14  SMPS

          i)switched mode power supply.

         ii)to supply power to computer and its parts.

         iii)Converts Alternate current(AC) into Direct Current(DC)

1.15 POWER  CONSUMPTION OF PC

            The power consumption  of  pc  is around 180 watts excluding monitor.

Components	Power Consumption
Monitor	80-100 watts
Hard Disk Drive	80-100 watts
CPU	30 watts
CD-ROM	30 watts
Motherboard	20 watts
Video Graphics card	20 watts
RAM	10 watts
PCI card	5-10 watts
Floppy Drive	5 watts

1.16 ADVANCED FEATURES

1.16.1 Cache memory :

            i) A small fast memory, which is between the CPU  and the main memory.

            ii)CPU-Resident cache is called as LEVEL1 cache or primary cache.(256-512KB memory)

            iii)Motherboard-Resident cache is called as Level 2 cache.(512-1024KB memory)

           

1.16.2 ADVANCED I-O  INTERFACES

           

1.      USB(Universal serial Bus) : i)Plug and Play devices can be inserted without restarting the computer.

                                         ii)Allows multiple devices-up to 127- to run simultaneously on a computer

2.      I-O PORT : i)Non USB devices

                       ii)can  be connected through serial or parallel port.

3.      PCI interface : i)Peripheral component interconnect  interface is used for all kinds of expansion cards.

                        ii)All sorts of PCI expansion cards are available, including modems,  network cards, sound cards, and video cards.

4.      AGP port : Accelerated Graphic port  interface is used only for video cards.

5.      MIDI Port(Musical instruments Digital Interface) : To connect musical instruments to the system.

6.      Game port : To connect gaming devices to the system.

1.17 CONFIGURING SPECIFICATION OF A PC:

           

1.       Cost:             i)Selecting the components according to budget.

2.      Intended use: i)Selecting the components according to the purpose.

                        ii)Purposes can be office applications , internet surfing, gaming, audio or video editing, music composition etc…

3.      Lifespan:         i)Selecting the current components for the longer duration.

4.      Reputation:    i)Selecting the components according to reviews, newsgroups, and message boards.

5.      Operating system: i)Most of the present computers are with the OS WINDOWS.

                             ii)System components should support, when the purchase is a non Microsoft windows OS.

6.      Compatibility: Reviews can be gathered from newsgroups and message boards about the selected components.

Plug and Play Devices

i.     Plug and play USB devices: i)Devices like keyboards, modems, external hard disk, external CD drive, pen drive, scanners, printers and video devices can be attached easily.

                                       ii)Can be attached through USB ports without switching off or restarting the system.

ii.      Plug sand play cards: i)These cards can be inserted or removed while the system is on preserving data integrity.

                                         ii)The cards such as fax card. Modem card, sound card and AGP card can be  fit easily which are plug and play in nature.

iii.    Expanding the main memory: Main memory can be expanded by adding memory modules.

iv.    Adding HDD, FDD and CDROM drive :These drives can be added to computer through IDE connecters

v.      PC card:  i)Personal computer memory card industry  association Or PCMCIA card or PC card is a small device.

                ii)Designed specifically for notebook and laptop computers but available for desktops also.

              iii)PC cards are used to add memory and plug and play in nature.

          vi) UPS : i)Uninterruptible Power Supply. Can be used during power outage.

                          ii)Types are, Offline UPS(Standby Power Systems) and Online UPS systems

1.18 COMPUTERS MAINTENANCE :

                  i)Both software and hardware must be considered.

                 ii)Maintenance contract can be taken out either with the hardware supplies or with an independent third party.

               iii)Hard ware maintenance comprises preventive maintenance cover.

               iv)Software maintenance comprises correction enhancements and updates.

1.18.1 Typical cause of system failure

1.      Component Failure : i)Thermal stress(hot and cold adverse) can  break the bond from the pad on the chip  causing an input/ output error.

                                ii)Remedy is replacing  the chip.

2.      HEAT: i)Destroy the chips inside the computer.

           ii)Remedy is installing an adequate fan or auxiliary fan in the power supply

      3.Dust an other particles :i)Causes thermal insulation due to dust in internal components.

                                             ii)Blocks the spaces such as  the air intake area to the power supply or hard disk.

                                       iii)Remedy is blowing the dust off with a can of compressed air.

3.      Noise interference: i)Electrostatic discharge form the human body and improper connections are  noise creators.

                      ii) Remedy is antistatic spray on rugs, carpets and computer equipment .

                     iii)Installing an antistatic floor mat beneath the computer chair.

4.      Power line problems: i)Causes by overvoltage or under voltage.

                                      ii)Remedy is Backup power supply(UPS)

5.      Magnetic fields: i)Voltages   monitors and television receivers produce strong magnetic fields.                                                                                                                     ii)Remedy is keeping the diskettes, tapes and even the information cables away form power sources and magnets.

6.      Corrosion: i)Causes by metal connector pins or cables, interface  cards, and chip pins.

                 ii)  Rub the pins clean to prevent corrosion.

1.18.2 Computer periodic check up

1.      Update the virus definitions                        2.Perform a full virus scan

               3.Reboot when programs crash                       4.Do a complete back up

               5.Run a spyware and adware removal program 6) Update the programs

               7)Check for new drivers                                 8)Clean out pc case

1.19 computer viruses

                  Symptoms of a computer virus

                The Computer,

1.      Runs slower than usual.

2.      Stops responding.

3.      Disks or disk drives are inaccessible

4.      Display unusual errors messages

5.      Display distorted menus and dialog boxes.

1.19.3     Definition:

i)A computer program that is designed to replicate itself by copying itself into the other programs stored in an computer.(OR) a destructive program.

ii)Causes the program to operate incorrectly or corrupting computer’s memory.

1.19.4 Types of viruses

                  1.  File viruses : Affect Executable  files

2.      Boot viruses:  Affect Boot sector or files.

3.      Macro viruses: Affect MS-office files. (spreadsheets and database)

4.      Network Virus: Spreads through emails

Example for virus.  :    Bomb, worm, and Trojan horse

1.20 COMPUTER SECURITY: Computer security refers to protecting computer systems and the information they contain against unwanted access, damage, modification or destruction.

                  1. Physical access restrictions: i)Access to authorized people.

                                                              ii)Access can be granted through identity card, user name and                  password, voice print, retinal scans, fingerprints and so on.

                                                              iii)Many systems use a combination of more than one control.

2. Password: A code by which a user gains access to a computer system.

                  3.Firewall: i)A software that usually runs on a proxy server of an organization

                                      ii)Controls the flow  of incoming and outgoing messages.

                  4.Backup :Duplicate set of program or data files in case the originals become damaged.

 ************WE WILL MEET IN CHAPTER 10****************