INTRODUCTION TO ISASInformation search and analysis skill(ISAS) seminar: is to gather

information, analyze & present. • Does not involve conventional way of teaching.• Emphasis is shifted from teacher-oriented to student-

oriented methods.• Information are gathered from various sources.

Aims

a) To develop search skills

b) To impart skills on : reading, cross references, abstracting, summarizing & presenting conclusions.

Books Internet

Magazines

Sources

SYSTEM UNIT

• The system unit is a box-like unit. • Contains number of useful components.• Each components has its own discrete function.• All components work to accomplish main function of

computer.• Sometimes called

the chassis

COMPONENTS OF SYSTEM UNIT

Internal power supply Exhaust fan Speaker Motherboard Chipset Microprocessor Clock chip Memory-RAM & ROM Bus Ports Expansion slot

Internal Power Supply

Component of system unit. Converts AC input to DC output of 5-10 volt. Also called Switched Mode Power Supply(SMPS). Provides cable connectors to supply the required voltage to

the other internal components like : the floppy drives, the hard disk drive, the motherboard & external device such as the keyboard.

EXHAUST FAN

The SMPS has a small fan, called the exhaust fan. The exhaust fan rotates as long as the computer is switched

on. Functions to cool the SMPS.

SPEAKER

System unit has a audio speaker. It is connect to motherboard. Produces sound whenever instructed by software programs. Example: when the machine starts, a self-test program is

executed that uses beep to indicate that everything is working satisfactorily.

Also used by entertainment programs to produce sound effects.

MOTHERBOARD

It is a large board present in a system unit. Contain a number of tiny electronic circuits & other

components. All peripheral devices are connected to the motherboard. It is also called system board.

COMPONENTS OF MOTHERBOARD Chipset A group of integrated circuits, or chips, designed to work

together. Connects the motherboard components.

Controls the system & its capabilities.

All components communicate with the processor through chipset, also called “hub” of all data transfer.

Upgradeable only with a new motherboard.

Determines the speed of motherboard.

MicroprocessorA microprocessor incorporates most or all of the functions of a computer's central processing unit (CPU) on a single integrated circuit (IC, or microchip).

Entire design of PC is base on the microprocessor. Hence CPU is often called processor. It contains CU, ALU. These component work together to perform processing.

ProcessorControl

UnitArithmetic

Logic Unit (ALU)

InformationData

Information

Memory OutputDevices

InformationInputDevices

Data

Information

DataInformatio

n

StorageDevices

Operation of CPU comprises of a Machine Cycle.

Processor

Control Unit

Memory

ALU

Step 1. Fetch Obtain program instruction or data item from memory

Step 2. Decode Translate instruction into commands

Step 3. Execute Carry out command

Step 4. Store Write result to memory

Other functions:Can move data from one memory location to another.Can make decisions & jump to new set of instructions.

Capacity of microprocessor is measured in terms of bits it can send or receive & process internally.

Some of the microprocessor introduced from time to time are:The Pentium (1993).The Pentium II (1997).The Pentium III(1999).The Pentium IV(2000), the fastest of among all four.

Pentium® family Itanium® or Xeon

Clock chipIt provides the timing signal.

Signal is provided in the form of electronic pulses.

The chip generates a regular beat & the operations of the computer are timed to this beat.

Unit: MHz(Mega Hertz) & MIPS(Million Instructions Per Seconds).

It is like baton held in an orchestra by the conductor.

Memory Two types:RAM (Random Access Memory)Memory used by computer to store & data while working on the system.It functions as scratch pad.

Characteristic:Data can be read/modified.Contents are lost when computer is switched of. Hence, it is volatile.Capacity depends on chip installed.

Types:Double Data Rate (DDR), Rambus Dynamic RAM(RDRAM),Synchronous Dynamic RAM(SDRAM) & Dynamic Ram(DRAM).

RAM CHIP

ROM (Read Only Memory)

It contains permanently recorded instructions, vital for starting up a computer.

One set of instruction found in ROM is called the ROM-BIOS(Read Only Memory Basic Input-Output Services).

It is non-volatile. ROM CHIP

BusIt is a set of wire.

Used to communicate between microprocessor & memory chip & other chip.

Data bus: bus with 8 wires carrying data.

Address bus: bus carrying address.

BUS

Ports These are inlets & outlets of microprocessor.

Port connects external devices to system unit.

Typesi. Serial portsii. Parallel portsiii. USB portsiv. Audio portsv. Infrared ports

Serial ports Parallel ports

Transmits one bit of data at a time.Connects slow-speed devices, such as mouse.

Transmits more than one bit data at a time.Uses devices like printer.

EXPANSION SLOTS

A set of sockets in the motherboard.

Help to attach extra input/output devices.

With Plug and Play, the computer automatically configures cardsand other devices.

CONCLUSION

System unit is the HEART of the computer.

WITHOUT SYSTEM UNIT

=

COMPUTER EMPTY BOX+

SYSTEM UNIT EMPTY BOX

=

SATISFACTORILY WORKING COMPUTER

REFERENCES

Book FOUNDATION SEMESTER VOL I (NIIT) Internet www.wikipedia.com www.cs.gsu.edu/~csclxh/csc1010/Outline04.doc www.slideshare.net/.../chapter-4-the-components-of-the-system-u

nit www.coolnerds.com www.webtechpoint.com www.nanomc.com

HEARTFELT THANKS

Ms POULOMI DAS(Lecturer)

Ms JOYSREE ROY & Ms BHARATI RABIDAS(Team members)