Sect1 Types&Components of Comp System

8/9/2019 Sect1 Types&Components of Comp System

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IGCSE 0417IGCSE 0417INFORMATION AND

COMMUNICATION TECHNOLOGY

SECTION 1SECTION 1

TYPES & COMPONENTS OF

COMPUTER SYSTEM


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Candidates should be able to :Candidates should be able to :

Define hardwarehardware, giving examples Define softwaresoftware, giving examples

Describe the differencedifference between

hardware & software

Identify the main componentsmain components of a

general-purpose computer

Identify operating systemoperating system(GUI,

command line interface)

Identify different types of computertypes of computer

Describe recent developmentsrecent developments in ICT


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TYPES & COMPONENTS OF COMPUTERTYPES & COMPONENTS OF COMPUTER

SYSTEMSYSTEM

HARDWARE

SOFTWAREDIFFERENCE

H/W & S/W

MAIN

COMPONENTS

OPERATING

SYSTEMTYPES OF

COMPUTER

RECENT

DEVELOPMENTS

SECTION1


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Components of A Computer SystemComponents of A Computer System

Computer

System

Hardware

Software

Data

Networks


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1) HARDWARE1) HARDWARE

y The physical partsphysical parts (plastic, metal, etc) of

the computer

y Including itemsitems insideinside the computer such

as graphic card, processor, memory and

hard disk

y Also includes devices connecteddevices connected to the

computer (monitor, keyboard, mouse,printer)


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Examples ofExamples ofhardwarehardware


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2) SOFTWARE2) SOFTWARE

y Consists ofinstructionsinstructions, codecode and

programsprograms that enable the computer to

perform specific tasks


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Categories of

SOFTWARE

System Application

Operating

System

Utility

Programs

Translator

Programs PackagesProgramming

Languages


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OPERATING SYSTEMOPERATING SYSTEM

y A program that controls & operate the

computer system

y Main functions :Controls hardware to get maximum use

Handles common jobs (copy files, save data,

etc)

Works as interface between a user and thecomputer hardware

OS Interface


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APPLICATION SOFTWAREAPPLICATION SOFTWARE

y Packages that perform many different

related tasks

y General-purpose software

y Example :

Word Processing packages

Spreadsheets packages

Database Management packages

Graphic packages

Communication packages


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y Translator Programs

Used to convert high-level languageinstructions into machine code

y Programming Languages A set of step-by-step instructions given to a

computer in a computer understandable

language

Example :C language, Visual Basic, JAVA

y Utility Programs

Perform tasks that are often needed &

common to all applications

Example : Backup utility, Defragmenter,

Scandisk


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3) What are the difference of3) What are the difference of

hardware & software?hardware & software?

Lets discuss


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4) MAIN COMPONENTS OF4) MAIN COMPONENTS OF

A COMPUTERA COMPUTER

* CPU(Central Processing Unit)

* Main / Internal Memory (ROM,RAM)

* Input Devices* Output Devices

* Secondary / Backing Storage


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Central Processing Unit (CPU)Central Processing Unit (CPU)

y Also called a processor or

microprocessor

y The brainbrain of the computer

Search, sort, calculate & make decision

y A very complex chip attached to the

motherboardmotherboard in the system unit

IntelIntel PentiumDPentiumD (exterior)(exterior)

CPUExamplesCPUExamplesy Intel Core family i7, i5, i3(Windows PCs)

y Quad-Core Intel Xeon

Nehalem (Apple Macintoshes)

y Intel Itanium2 (servers)

Main Components of A Computer #1


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y Central circuitboard of the

computer

y All components

& peripherals

are plugged into

it

y

Job :To relayinformation

between

components &

peripherals


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* Consists of : Motherboard

Storage unit (including

drives) Power supply unit

Expansion cards


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Central Processing Unit (CPU)Central Processing Unit (CPU) cont..cont..

-- Basic operation of a computerBasic operation of a computer

(In CPU)

Eg: Keyboard

Eg: Hard Disk

Eg: Monitor


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Central Processing Unit (CPU)Central Processing Unit (CPU) cont..cont..

y Measured in megahertz (MHz) togigahertz (GHz)

y

1MHz CPU can carry out 1 millioninstructions per second;1GHz = 1 billion

y Threemain pa

rtsof CPU :

Arithmetic and Logic Unit (ALU)Arithmetic and Logic Unit (ALU)

Control Unit (CU)Control Unit (CU)

Data RegistersData Registers


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CPU :Control UnitCPU :Control Unit

y Controls & monitors the systems

hardware to ensure that commands given

to the application software are used

y Controls the input & output of data so

that the signals go to the right place at

the right time

y Controls the flow of data within the CPU


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CPU : Arithmetic Logic UnitCPU : Arithmetic Logic Unit

y Where all the calculations & decisions take

place

y Consists of two parts :

Arithmetic partArithmetic part performs calculations

e.g., add, subtract, multiply, divide, square root, cosine,

etc. Logic partLogic part deals with logic & comparisons

e.g., compare two numbers to see which is greater,

check whether a true-false statement is true, etc.


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CPU : Data RegistersCPU : Data Registers

y Hold data that is

on its way into,

or out of, the

ALU

y Once data has

been processed,

it is stored in themain memory

(RAM)


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Main / Internal MemoryMain / Internal Memory

y Name given to the group of chips inside

the system unit

y Computer could directly access the data

held in the memory

y Fastest access compared to other storage

y Two main types :

1.1. RandomAccess Memory (RAM)RandomAccess Memory (RAM)

2.2. Read Only Memory (ROM)Read Only Memory (ROM)



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Random Access Memory (RAM)Random Access Memory (RAM)

y Used for temporary storage of

data & instructions For processing

yy VolatileVolatile Data is lost when power is turned off

y Much faster than storage devices

(eg: hard disk)y Re-writable


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Functions ofRandom Access MemoryFunctions ofRandom Access Memory

y Temporary store for programsprograms (which are

currently running) and datadata (that is currently

being used)

y Store data that is being transferred to & from

peripheralsperipherals (eg: printer)

y Store outputoutput data (ready to be sent to output

unit)


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Read Only Memory (ROM)Read Only Memory (ROM)

y To store permanent data/programs

Created at the manufacturing stage

y Contents cannot be changed

yy NonNon--volatilevolatiley Non re-writable (can only be read)

y Contains essential instructions to :

Enable the computer to check the

hardware

Operate the hard disk to load the OS

stored there


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Application ofRead Only MemoryApplication ofRead Only Memory

y To store frequently used programs that are

essential to normal running of computerx Which give basic hardware configurations

y To store bootstrap programsx That tells the computer how to load the OS

from disk to RAM

y POST(Power on self-test)x Checks the hardware when PC is switched on


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Input DevicesInput Devices

y Used to input or capture data into a

computer system

y Peripheral devices that accept data &

transfer it in a digital form to the processor



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Output DevicesOutput Devices

y Used to display or transfer data from the

computer

y Provide results after processing

y Hard copy (printout), on screen (soft copy),

audio or electronic message (e-mail)



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Secondary / Backing StorageSecondary / Backing Storage

y

To store data for later use and in vast quantitiesx Can be retrieved when needed

y Three types of storage device :

1.1. OpticalOptical

Uses a precise laser light beam (eg:CDs & DVDs)

2.2. MagneticMagnetic

Uses a magnetic medium (eg: hard disks & magnetic

tape)3.3. Solid stateSolid state

Uses electronic circuits that retain the values without

any power source (eg:USB memory sticks & camera

cards)


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Secondary / Backing Storage cont..Secondary / Backing Storage cont..

y Devices for storing permanent, non-volatile data

include:

x Hard disk, CD, DVD, USB memory stick,

Magnetic tap

e

y Writable devices are available to record data to

CD and DVD discs


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5) Operating System Interfaces5) Operating System Interfacesy R

e-cap definition ofOSOS

yy User interfaceUser interface provides the means of

communication between users and information

system

xShould be easy to use & understand

x Cursors, prompts (visual/audible), icons, menus, etc

y Categories of user interface:

Command Line InterfaceCommand Line Interface

Graphical User Interface (GUI)Graphical User Interface (GUI)


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Command Line InterfaceCommand Line Interfacey Instructions/commands are typed in order to

get something done

y Used in early computer systems

y Not easy to use

y User has to remember all the commands

x Commands vary with different software

x Provide fast access to functions of the system

y Incorrect command will get error messagey Uses a prompt where the user types in a

command

Eg: C:\ (for hard disk) or A:\ (for floppy disk)


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Features ofCommand Line InterfaceFeatures ofCommand Line Interface

y A fast interface for expert users who use a

limited set of features frequently

y Specific and powerful instructions which can

be given directly


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Example ofCommand Line Interface

C:\> dir/w

Volume in drive C: has no label

Volume serial number is 1DF4-1D18

Directory of C:\

[ACDSEE32]

[MY DOCU~1] [RICAZ] [LETTERS]

[WINZIP]

CAMBRIDGE.DOC

1 file (s) 23,345 bytes14 dir (s) 236, 234, 345 bytes

free

C:\>show directories

Bad command or file name


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Advantages ofAdvantages ofCommand Line Interface

Suitable for experts but not casual users because:y Significant training is needed to be able to use it effectively

y Text commands must be known (not provided)

y Commands must be typed correctly & follow the required syntax

y There is only limited help available

To view command line interface in Windows XP

y Start > Programs > Accessories > Command Prompt

To view command line interface in Windows 98

y Start > Programs > MS-DOS Prompt


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Graphical User Interface (GUI)Graphical User Interface (GUI)

y Most popular because more user-friendly

y Consisting ofwwindows, iicons,mmenus & ppointers

(WIMPWIMP)

y

Have windows that enable a user to easily view,control & manipulate multiple things at once

y Features :

WindowsWindows that can be moved & resized

IconsIcons that represent the action to take

MenusMenus that group functions together

PointersPointers that can be used for selecting


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Advantages ofGUIAdvantages ofGUISuitable for most users because it is:

yy FriendlyFriendly - Can be used without reading the whole manual first

yy AttractiveAttractive - Colour & simple presentation improve legibility & directthe eye to key words

yy IntuitiveIntuitive - No need to learn how to use the icons or memorisefunctions before you can explore the interface

Content-sensitive:Only presents functions that can be performed on

a chosen object

yy ConsistentConsistent

Often the same icons/menus can be found in different applications.The

icons have the same function & menus have the same structure

yy CustomisableCustomisable Several features (font size, icons, menus) can be personalised

yy SupportiveSupportive

Help is easily available & can be shown automatically, eg: screen tip

(place mouse over an icon)


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6)Types ofComputer6)Types ofComputerComputers are grouped according to :

y Size

y Processing power

y Design

y

Cost

Types of computer:y Personal Computer / Desktop

y Mainframe

y Laptop

y Palmtop

y Personal Digital Assistant


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MicrocomputersMicrocomputers

y Single user system

y Most commonly used (at home, in school,

businesses)

y Small, cheap, relatively slow & limited

memory

y Can be further divided into :

a)a) Personal Computer / DesktopPersonal Computer / Desktop

b)b) LaptopLaptop


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Personal Computer / DesktopPersonal Computer / Desktop

y Features of a PC usually include: Monitor, keyboard, mouse, case containing

motherboard with CPU,RAM & hard disk,

CD, DVD or combined drive

y Can work alone as a standalone

computer or connected into a network

like a LAN

Eg: IBMNetvista, Apple Mackintosh, Dell

Optiplex, ect

y Fits on a desk and runs on power from an

electrical wall outlet


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Personal Computer / DesktopPersonal Computer / Desktop

Useful for lots of different types of tasks:y Running office applications

y For CAD such as designing kitchens

y Editing videos

y Creating and playing music

y Accessing the Internet for research, work

& entertainment


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LaptopLaptop

ComputersComputers y Also known as notebooks

y Light, portable, battery-

operated, suitable fortravelling

y Low power, miniaturisedcomponents & thin film

transistor (TFT) screen


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Laptop ComputersLaptop Computers

y Can also be placed into adocking station which has

connections to a printer,

network & power supply


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y For ultra-light& thin laptops,

DVD/CD-

ROM drives

are connected

to the

computer only

when needed


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MainframeMainframe Large, very powerful, multi-user

system (hundreds ofsimultaneous user)

Can execute billions of

instructions per second & can

process large amounts of datasimultaneously

Occupy a large air-conditioned

room & have vast memories

Peripherals are mounted in large

cabinet type frames

Eg: IBM3090, ICL series 39


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Uses ofMainframesUses ofMainframes

y Used by large companies for data processing, by

scientist for complex mathematical calculations and

as network servers on the Internet

y Example :

Utility companiesUtility companies e.g. gas and electricity suppliers to calculatee.g. gas and electricity suppliers to calculate

customer billscustomer bills

BanksBanks -- for managing thousands of customers accounts each dayfor managing thousands of customers accounts each day

Insurance companiesInsurance companies -- for keeping track of policies and claimsfor keeping track of policies and claims

AirlinesAirlines -- for dealing with bookings, tickets, cancellations etcfor dealing with bookings, tickets, cancellations etc

PolicePolice -- for storing and processing all of the data collected eachfor storing and processing all of the data collected each

day about crimesday about crimes


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PalmtopPalmtop

y Small enough to fit in ones palm

y Very similar to a PDA in their use,

except it has a built-in keyboard

y Although some palmtops are like

PDAs in that they accept

handwritten or touch screen

input, they generally differ in thatthe palmtop has more memory, a

keyboard and a greater variety of

available programs


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AssignmentAssignment

y Do a research entitled Recent Development InRecent Development In

ICTICT with a partner

y Choose only ONE development and elaborate on

that (maximum 2 pages)

y Do not print directly from the Internet, pleaseedit and format your assignment using a word

processor

y

State your source (name & author of books, fullwebsite address, etc)

y Any identical assignments from different groups

will be penalised (aka RE-DO!!)

Documents

Sect1 Types&Components of Comp System