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A computer system refers to the entire computer and all the devices and component related to the computer (environment).

computer system and introduction computer system

Definition of a computer:

A computer is an electronic device capable of receiving data in the form of input, stores this data, process these data and sending out the result (information) in the form of output.


A computer system is practically divided into three parts;


These are the components related to the computer environment which can neither been seen nor touch. It generally refers to programs installed on the computer that tells the computer how to interact with the users.

Examples of software includes those that can carry out text product, video editing, graphics design or web browsing.

Computer software is further divided into 3 divisions

i)                   System software.

System software refers to the governor program of the computer. They are divided into operating system and compiler. They coordinate and controls hardware and operations in the computer and it devices.

Example of system software includes; MS DOS, WINDOWS (e.g. XP, VISTA, SEVEN, 98, ETC), LINUX, UNIX, Mac O.S, Device drivers, Programming languages, utility programs etc.

Operating system: They are defined as system software capable of controlling and managing soft and hardware operations including memory and disk storage.

The most common operating systems are; Windows (the most popular world known), Mac O.S, Apple Mac OS X. they operate on GUI (some time called gooey). The advantage of GUI is that it provides the ability to carry out multitasking (i.e., working on many windows at once). It also provides the ability to use graphical icons and text to execute task or to run programs rather than typing instructions as in the MS DOS (the first operating system).

Without the operating system, the computer is useless. Some measure functions of the operating system comprise;

–       Running applications: Calling package such as Microsoft Word so that the user can interact with them directly.

–       Running programming languages: This is a situation where the user can create a new program using a program editor.

–       File Management: Creating, moving, copying, pasting, deleting, merging files on disk or other storage.

–       Device management: This is when the operating system instructs the computer on the use of different peripheral devices such as, printer, display, keyboard, etc.

We have two types of operating system i.e. the server operating system use for a computer instructing or sharing data with other computers on the network and the client operating system that can only accommodate a single user at a time hence designed for personal use.

Utility programs: These are programs that perform task involving computer disk management system and use of hard ware resources disk drives and printers. Their function covers disk formatting (dividing the disk into sectors so as to use it to store information) and disk decrementing (rearranging files on a disk in an orderly manner). They include;

–       Memory management software for handling locations in the RAM where programs put their current data.

–       Disk checker to scan the content of a hard disk to identify portions or files that are corrupt or not correctly saved and delete them.

–       Backup program to copy all information stored on a disk and restore them in case of disk failure or accidental deletion.

–       Data compression program to reduce a data so that it requires less storage space.

–       Disk defragmenter to identify files whose content are broken across several locations and bring them to one so as to increase efficiencies.

Device drivers: A device driver is software that allows the computer controls a peripheral device. It is this driver the translate responses from the computer to the device and from the device back to the computer.

Computer programming languages: They are sometime called compilers use by programmers to write programs by translating the instructions into electrical signals.

Compilers are programmes installed on a computer to convert data from a high level language to a language that is understandable by the computer.

Compilers are usually use for programming. Examples includes; JAVA, C++, C, PASCAL, COBOL, Visual Basic, etc.

ii)                Application software

These are programs or software installed on a computer to carry out particular functions. These programs can be installed on a computer only after the operating system has been installed. Example of application software includes;

Word processing software,

Spreadsheet software,

Data Base management software,

Presentation software,

Computer Aided Design

Desktop publishing software,

Accounting software,

Paint and image editing software,

Video and audio editing software,

Multimedia authoring software,

Web page authoring software.

Application software is made up of Productivity software and Connectivity software.

Productivity software: it is designed to be use by business or organization, it help users to work more effectively. E.g. spreadsheet, word processing etc.

Connectivity software: Connect a computer to a local area network or the internet and provides tools that you can use to take advantage of the information and communication they offer.

An antivirus is use to protect a computer system from virus attack.

A virus is programmes designed by software engineers and publish to the internet. These programmes are downloaded automatically by computer while browsing the internet. These programmes when present in a computer, cause the computer to function negatively (malfunction).

The effect is usually slowness of the computer, freezing of the computer or malfunctioning of other programmes which includes unnecessary lost of data or information.


This refers to the computer components which can be seen and touch. They are made up of electrical circuit and mechanical parts. Hardware devices can function as input, processing and output devices. Hardware components provide the working space for software’s.

Storage devices are also examples of hardware components. Example of hardware components include; mouse, keyboard, printer, hard disk drive, etc.


This refers to the persons working on the computer. This idea of people ware has been introduced here because the computer hardware and software components can not work on their own, a human being is needed to instruct the computer on what to do at a particular time.


LCD         : Liquid Crystal Display

USB          :Universal Serial Bus

MAN         :Metropolitant Area Network

LAN          : Local Area Network

WAN         : Wide Area Network

RAM       : Random Access Memory

ROM           : Read Only Memory

HDD           Hard Disk Drive

DVD           : Digital Versatile Disc

CD              : Compact Disc

VCD           : Video Compact Disc

SDRAM       Synchronous Dynamic Random Access Memory

IP               : Internet Protocol

VGA          : Video Graphics Accelerator

RW            : Rewritable

MSDOS     : Microsoft Disk Operating System

ALU          : Arithemetic Logical Unit

CPU          : Central Processing Unit

SU             : System Unit

CRT          : Cathode Ray Tube

ISP           : Internet Service Provider

GUI          : Graphical User Interface

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