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ITConcepts of information technologyConcepts of information technology

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Types of ComputersTypes of Computers Mainframe ComputersPC ( Personal Computer )Networked ComputerLaptop PDA ( Personal Digital Assistant )

Mainframe computerMainframe computer DescriptionAre big , powerful , expensive computers used by most large

organization Capacity : very power full computers SpeedVery Fast in processing data Costs : very expensive UsersLarge companies including banks...

( (PCPC ) ) Personal computer Personal computer DescriptionIBM invented the pc since 1981 Capacity : large hard disk SpeedFast normally measured in GHz Costs : Getting cheaper by day UsersHome users , Doctors , Education …..

Networked ComputerNetworked Computer DescriptionAllow you to connect two or more than one computer together Capacity : large hard disk SpeedFast normally measured in GHz Costs : A pc need inexpensive card to connect to network UsersHome users , Doctors , Education , any one…..

LaptopLaptop DescriptionSmall , Portable , Can run on batteries as well as main power Capacity :Large hard disk, often less powerful than PC which is equivalent in price SpeedFast normally measured in GHz – Speed specification are less than PC

which is equivalent in price Costs : Exceeds when compared with PC UsersBusiness users , People on the move , Educational user

PDA ( Personal Digital Assistant )PDA ( Personal Digital Assistant ) DescriptionUse a special pen rather than keyboard, can store and retrieve

information Capacity : Much smaller than PC SpeedMuch slower than PC Costs : Exceeds when compared to PC Users : Mostly Business Users

HardwareHardware

Computer Computer ComponentsComponents

System UnitSystem UnitThe name given to Main PC box

It Houses items like ….• Mother Board • CPU• RAM • CD• Floppy Disk

System (Mother ) BoardSystem (Mother ) Board All items of the system unit attached to Mother board ,

either directly or via cable

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

IT is one of the most important components within Computer

It is the brain within your Computer It performs most of the calculation within the

computer It determines How fast you Computer will run It is measured by GHz 2 GHz Pentium is much faster than 1GHz Pentium

MemoryMemory

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

•It’s where the operating system is loaded when you switch on your computer

•It’s where your application are copied to when you start application (such as word processing )

•Volatile and changeable

•The more RAM you Have installed in you Computer is better

•It is measured by MB•These days you will commonly find over 512 MB of Ram installed

ROM - BIOSROM - BIOS ( Read only Memory – Basic input out put system ) ( Read only Memory – Basic input out put system )

It is special chip held on your computers’ mother board

It contains Software which makes your computer work with your operating system

It is Non volatile, unchangeable

Serial PortSerial Port

It is socket located at the back of your computer which enable you to connect items to the computer , such as Modem

Parallel PortParallel PortIt is socket located

at the back of your computer which enable you to connect items to the computer , such as Modem

USB (Universal Serial Bus )USB (Universal Serial Bus ) It is Relatively new

item within the PC You will see one or

more USB Sockets at the back of Your computer

It enables you to Plug in devices such as Printer, Scanner, Digital camera .

Input And Output Device

Input DeviceInput Device.… .…

Key boardMouse Tracks ball Touch padLight penJoy stick

ScannerWeb Cam Digital Camera

Input device allow you to input Data to the computer

Key BoardKey Board

Key board is the commonest way of entering data to the computer

MouseMouse The mouse came into

common use on PC with the introduction of Microsoft operating system (Windows) .

Before this (DOS) operating system had been controlled via the keyboard

Tracker ballTracker ball

A tracker ball is an alternative to the mouse.

A tracker ball is favorite by graphic designers.

Touch padTouch pad

Touch pad can be used by graphic artists

Light penLight pen

A light pen is used to allow users to point to areas on screen and its often used to select menu

Joy stickJoy stick

Used in games

ScannerScanner

A scanner allows you to scan printed material and convert it into a file format which may be used within PC

Web CamWeb Cam

Ever since it was invented , the web has become increasingly interactive .

It allows you to communicate in two ways not just text communication but also sound and video

Digital CameraDigital Camera

A digital camera can be used in the same way of traditional camera but instead of storing images on rolls of films , the images are storing in memory housed within the camera ,this images can easily be transferred to your computer

Output DeviceOutput Device.… .…

Computer monitorFlat screen monitorComputer presentation projection devicePrintersspeakers

Output devices allow you to output information From the computer

Computer monitorComputer monitor

The VDU ( Visual Display Unit ) is the computer screen used to output information.

Flat screen monitorFlat screen monitor Flat screen

computer monitor have become available , these take less size on the desk and use less energy than the traditional

Computer presentation Computer presentation projection deviceprojection device

It can be attached to your computer and it is useful to display presentations to group of people.

PrintersPrinters

Laser PrinterColor laser printerInkjet printersDot matrix printersPlotter

SpeakersSpeakers

Output / Input DeviceOutput / Input Device.… .…

Touch screen

Some devices are both input / output devices

Storage DeviceStorage Device

Hard desk ( Internal – External )Zip DriverDisketteCD deskDVD driverJaz DisksBack up tape

Hard diskHard disk Internal Hard Disks

Speed: – Very fast! – The speed of a hard disk is often measured by “RPM" speed,

The smaller this number the slower the hard disk. Capacity: – Enormous! Often in excess of 10 Gigabytes. A Gigabyte is

equivalent to 1024 Megabytes. Cost: Getting cheaper by the day

External Hard Disks

Speed: – Normally slower than internal disks, but more expensive,

offer the same performance as internal hard disks. Capacity:

– Same as internal disks. Cost:

– More expensive than internal disks.

Hard DisksHard Disks

DVD DrivesDVD Drives

Speed: – Much faster than CD-ROM drives

but not as fast as hard disks. Capacity:

– Up to 30 G bytes. Cost:

– Slightly higher than CD-ROM drives.

CD-ROM CD-ROM (Compact Disc)(Compact Disc)

Speed: – Much slower than hard

disks. Capacity:

– Around 650 Mbytes.

Zip DisksZip Disks

Speed: – Slower than hard disks but ideal for backup.

Capacity: – 100 or 250 Megabytes.

Jaz DisksJaz DisksSpeed:

– Slower than hard disks but ideal for backup.

Capacity: – Around 2 Gigabytes

(2048 Megabytes).

Diskettes (Floppy Disks)Diskettes (Floppy Disks)

It can be write protected to prevent data from changes or infection of viruses.

Speed: – Very slow!

Capacity: – Normally 1.44 Mbytes.

Cost: – Very cheap.

Back up TapeBack up Tape

Used to archiving the files that are not needed

Storage measurementStorage measurement Tera byte = 1024 Giga byte Giga byte = 1024 Mega byteMega byte = 1024 Kilo byteKilo byte =1024 Byte Byte = 8 Bit

SoftwareSoftware

Types of Software

Operating SystemApplication Program

FormatFormat Unformatted disk need operating system data written to them

before they can store files. Pre formatted disk can be used immediately to store

data. Full formatting completely erase the previous contents

of a disk. You can purchase preformatted disk. You can reformat a used floppy disk.

Operating SystemOperating SystemThe operating system is a special type of

programs which is loaded automatically when you start your computer

There are number of different types of operating systemDOSWindowsUnix and LinuxMac/OS

DOSDOSIBM invented Pc Since 1981 And used

DOS Operating system.This operating system was very basic.You had to be computer expert just to

understand how to use computerIt was not user – friendly

WindowsWindows Microsoft introduced windows which is more

powerful than DOS and which is commonly used on PC today.

There are numbers of different types of windows

The main advantage of windows that it has a Graphical User Interface ( GUI )

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

It is part of operating system which display windows and drop down menus

The system using windows, icons to operate a computer It enables you to drive your computer by using mouse

Advantage

All programs look similar and when switches from a program supplied by one manufacturer to different program supplied by another manufacturer , you will find the transition very easy

By GUI its easier to learn and use Application Program

Unix & LinuxUnix & Linux

Are other examples of Operating Systems which may be run on PCs

Other Types of computers , Such as Manufactured by Apple

have a completely different operating System called

Mac/OS .

Application SoftwareApplication Software

An application program is the type of program which you use when the operating system has been loaded.

Can run more than one at the same time. Can be used to edit data type

Example …. Word Processor

Create letters, Faxes, Memos Spread Sheet ( Excel )

Make financial projects

With Charts Database ( Access )

Sort large amount of information Presentation ( Power point )Crate overhead projection or slides

•Desktop publish

Producing a newspaper with

complex page layout

•Accounts payroll ( Sage )

(Make financial projects )

large Organizations

Things to avoidThings to avoid Dust Drinking and eating over the key board Heat Moisture Don’t move the system while it switched on Follow the correct steps to shutdown your computer Don’t place object in the top of monitor Don’t place floppy disk near monitor . Monitor produce a

strong electromagnetic

System CycleSystem Cycle Most project work in cycle First step ( System analysis): Analyze the need of computer user. Second Step ( Design )Draw up the plans on how it can be implemented on a real. Third Step ( Programming )Convert the design to actual plan. Final Step ( Testing )Testing the software.