Functions of the main components of a system unit

No. Components Functions

1

Input/Output port (I/O port)

- A port is the point at which a peripheral attaches to a system unit so that the peripheral can send data to or receive information from the computer. - An external device, such as a keyboard, monitor, printer, mouse and microphone is often attached by a cable to a port on the system unit. - The back of the system unit contains so many ports. Some newer personal computers also have ports on the front of the system unit. - Ports have different types of connectors. A connector joins a cable to a peripheral. One end of a cable attaches to the connector on the system unit and the other end of the cable attaches to a connector on the peripheral.

2 Power button

To start on computer

3 Reset button

Kick of soft boot, instructing the computer to go through the process of shutting down, which would clear memory and reset devices to their initialized state. It simply removes power immediately.

4 Motherboard Main circuit board of the system unit, which has some electronic components attached to it and others built into it.

5 Power Supply

Convert standard electrical power into the form that computer can use. If a power supply is not providing the necessary power, the computer will not function properly.

6 DVD-ROM drive

A device that reads DVD-ROM, also can read audio CDs, CDROMSs, CD-Rs and CD-RWs.

7 CD-ROM drive

A device that reads audio CDs, CD-ROMs, CD-Rs and CD-RWs.

8

DVD/CD-RW

drive

It is a combination drive that reads DVD and CD media, it also writes to CD-RW media. This drive also allows watching a DVD or burn a CD.

9 Zip drive A high-capacity disk drive that reads from and writes on a Zip disk.

10 Floppy drive A device that reads from and writes on a floppy disk

11 Hard disk drive

Type of storage device that contains one or more inflexible, circular platters that store data, instructions and information. Also called a hard disk.

DEFINITION & TYPES OF PERIPHERAL

Peripheral Device

External hardware devices attached to the computer are called peripheral devices

There are three types of peripheral devices :

• Input devices

• Output devices

• Storage devices

Input Devices

Input devices are any electronic device that are connected to a computer and

produces

input signals.

Output Devices

Output is the result of data processing activity when it is presented externally to the

system. The output from a computer can be printed or displayed form .

An output device is hardware that is capable of delivering or showing information to

one or more users. An output device shows, prints and presents the results of a

computer’s work.

Storage Devices

Information and documents are stored in a computer storage so that it can be

retrieved

whenever they are needed later on.

Computer storage is the holding of data in an electromagnetic form for access by a

computer processor.

Units for Data Measurement

• Bit

• Byte

• Kilobyte (KB)

• Megabyte (MB)

• Gigabyte (GB)

COMPUTER SOFTWARE

Definition Of Software

Software is also called a computer program. It consists of a series of

instructions that tells the hardware of a computer what to do or how to do it. For

example, some instructions direct the computer to allow you to input data from a

keyboard and store it in the memory. Other instructions cause data stored in memory

to be used in calculations.

Usage Of Software

Software is used so that you can interact with the program through its user interface.

This user interface controls how you enter data, instructions and how information is

displayed on the screen.

Types Of Software - There are two types of software

1. System Software

System Software is used to control and manage computer devices and operations. It

consists of:-

o Operating System

�� A set of programs that coordinates all the activities among the computer

hardware devices

o Utility Programme

�� A type of system software that allows a user to perform maintenance type tasks

2. Application Software

Application software is all programs that perform specific tasks for users, which

include Word processing, spreadsheet, database, presentation, e-Mail and Web

browser Software. Examples of application software are Microsoft Word, Microsoft

Excel, Outlook Express and Internet Explorer.

SYSTEM SOFTWARE

System software consists of programmed that control the operations of the computer

and its devices. System software serves as the interface between the users, the

application software and the computer hardware. There are two types of system

software:

a. Operating System

b. Utility Programmed

a. Operating System

• An operating system is the program that is loaded into the computer and

Coordinates all the activities among computer hardware devices.

• It controls the hardware in the computer, peripherals, manages memory and files.

• It enables the user to communicate with the computer and other software

• Some examples of operating system are Microsoft Windows, Macintosh OS X,

Linux, UNIX and also DOS

b. Utility Programmed

• Utility programmed allows user to perform maintenance-type tasks.

• It has been integrated into most major operating systems such as format, check

and defragment disks

• Other examples of utility programmed are antivirus and file compression

programmed