Introduction to Computers Studies

computer basics



This introductory topic is intended to set the scene and help the student understand in details the basics of the computer system.

In this module, we will cover the following sub-topics

  • Basic Computers terms
  • Uses of the computer (role of the computer in our society)
  • Further Classification of Computers
  • Types of Computers.
  • Basic Elements (Functions) Of a Computer
  • Computers generations
  • Parts of computer

1.1 Basic Computers terms

  1. Computer; is a device that works under control of stored programs to automatically accepts, Stores and process data to produce information that is the result of that processing.
  2. Data; Data is the name given to the basic fact, e.g. the number of the items sold by a business, the name of the customer, a line of text, or the mathematical formulae.
  3. Information; when data is converted into a more useful or intelligible form then it is said to be processed into information.


1.2 Uses of the computer (role of the computer in our society)

  1. Education and research; Computers are widely used in education as teaching aids and research institutions. In aviation, computers are used to train pilots. Scientists use computers to analyze experimental data. Engineers and architects use computers to design, test and re-design.
  2. Health Care; Medical records on patients are today stored and retrieved from a computer for patients management purpose. Computers also today allow for access to otherwise inaccessible or prohibitively. Expensive foreign expertise or labor and make it possible for hospitals in one country to use consultants or even surgeons in another thereby reducing traveling for patients, businesspeople and professionals.

  3. Industry and Commerce; Almost every industry or service providers use computers in day-to-day operations. It’s known impossible to manage a large organization without the help of the computer. Apart from the track of orders and bills, computers play a strategic role in business by defining new products and services, maintaining


Competitive edge and providing new opportunities for management control. Leading companies are using computing technologies as a competitive tool to develop new products and services, forge new relationships with the suppliers, and edge out competitors.


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  1. Offices; in modern offices, computers are now routinely used for general office automation including text production, accounting services, clients information, desk-top publishing, stock control, point-of-sale terminals.
  2. Process Control; Computers are widely being used in the production environment to control chemical and mechanical processes. These are specialized applications, and each computer system has to be constructed to do a specific job.
  3. Communication industry; in the telecommunication industry, every telephone exchange today relies on computers to switch incoming and outgoing calls. Railway corporations rely on computers to coordinate the movement of their wagons and goods. In the airline industry, computers are heavily used in air traffic control and surveillance of air space using radar equipment as well as for reservation purposes.

  4. Police & Defence; Computers are nowadays used to fight crime. Police keep the database of fingerprints which are automatically analyzed by computers. In defense, computers are used in electronic news gathering, efficient communication, detection, and tracking of targets, radar systems, warning systems, and military laser and guided missile systems


1.3 Basic Elements of a Computer

  1. Input; It is necessary to present data in a way that provide easy conversation into its electronic pulse-based form. This is achieved by keying in data using a keyboard that changes it into machine sensible form.
  2. Storage; Data and instructions enter the main storage, and are held until needed to be worked on.
  3. Control; the processor controls the operation of the computer. It fetches instructions from main storage, interprets them and issues the necessary signals to the components making up the system.
  4. Processing; Instructions are obeyed, and the necessary arithmetic operations are carried out on the data.
  5. Output; Results are taken from the main storage and fed on an output device. This may be a printer which changes the information in a printed form called Hard copy.

Advantages of Using Computers

  1. Computers are in manipulating figures
  2. Have large storage capacities
  3. Occupies a small area in the office (working area)


Disadvantages of using Computers

  1. Computers are expensive to purchase
  2. One must be trained so as to use the computer
  3. Leads to unemployment
  4. Laziness in working out simple activities e.g. simple calculations
  5. Requires power to operate

1.4 Types of Computers.

  1. Personal Computer (PC); It’s designed to be used by an individual at work or in the home mainly for business purpose.
  2. Desktop Computer; Its any computer designed for use on a desk in an office enviroment.PC is a type of desktop computer.
  3. A Work station; is another kind of desktop computer. Although large more powerful PCs are sometimes called workstations the term is normally used to imply the presence of advanced features not provided by all PCs.
  4. Lap-Top; is a pc sufficiently small and light for its user to comfortably use it on his lap.A typical lap-top operates on mains electricity or rechargeable battery and is small to fit in a briefcase. Lap-tops normally have in-built disk drives and flat screen.
  5. Embedded Computer; is one that is within some other devices or system but is not assessed directly. e.g there are embedded computers working within petrol pumps, watches, cameras, video recorders and many types of domestic and industrial types of equipment.


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1.5 Further Classification of Computers

  1. Mainframes; Large general purpose computers with extensive processing, storage, and input/output capabilities.
  2. Mini computers; physically smaller computers compared with the mainframe. They are used for special purposes or small scale general purpose work
  3. Microcomputers; These represent a further step in miniaturization in which the various integrated circuits and elements of a computer are replaced by a single integrated circuit called “chip”.


1.6 Computer Generations

The first electronic computers were produced in the 1940s. Since then, a series of radical breakthroughs in electronics has occurred.

  1. First Generation; this was early computers using electronic valves. (the 1940s)
  2. Second Generation; More reliable computers using transistors that replaced the first generation computers (the 1950s)
  3. Third Generation; More powerful, reliable computers using simple integrated circuits (ICs) (1960 & early 1970)
  4. Fourth Generation; The computers in use today and which contains more sophisticated microelectronic devices such as complex integrated circuits which are classified as “Large scale integration”.
  5. Fifth Generation; There is predication that computers will be developed which will be able to mimic human senses, manual skills, and intelligence.

1.7 Parts of the computer

Hardwares; This is the physical components of the computer. They are mainly classified according to their functions i.e. input devices and output devices.

  1. Input Devices

These are devices that help the computer operator to input data in the computer. They include

  1. The Mouse; It is used to issue commands to the computer by activating certain spots on the screen. As the mouse moves on the screen, the cursor moves about the screen. The button is pressed when the desired position is reached. The motion of the mouse is sensed by a rolling ball, which is mounted on the underside of the mouse and is in contact with the desktop.
  2. Scanners; Are usually used to capture existing documents in an electronic form for further processing or incorporation to other documents. Text and graphics can be scanned, and images can be manipulated by changing colors, the sharpness, and contrast, etc.
  3. Point Of Sale Terminals; Computerrised wholesales or supermarkets, serve the customer through a point of sale terminal. The item code, quantity, and the price of goods purchased by the customer are entered into the POS terminal directly by the operator. The terminal produces customer receipt.

  4. Bar code reader; each item in the store is labeled with a universal product code identifying the item. Most supermarkets today use this system, and the codes can be seen on every item purchased.
  5. Light Pens; A light pen consists of a stylus connected by a cable to the terminal. The position of the stylus is noted, and a dot appears on the screen when the stylus is brought into contact to the screen.
  6. Credit card. Accredit card has a strip of magnetic tape fixed on it, containing coded information which is usually the owner’s code. The card is inserted into a slot where magnetic data may be picked. Details of the transactions are then recorded against the credit card number, and the owner’s account is credited with the transactions.

  7. Optical Character Readers; These readers are popularly used to process turnaround documents produced as output and are reused as input by the an electricity bill is printed with all the information required for the re-input on the rear off section
  8. Optical Mark Reader (OMR); Light is shone onto the paper and the reflected light is detected. The presence of a mark is detected due to lesser light being reflected from the mark. Optical Mark Reader is a device that can detect the presence or absence of a mark on a paper. Mostly used to read Questionnaires which has multiple choices whereby one is selected.
  9. The Keyboard; It’s the common input device for microcomputer systems

The keyboard consists of the:

  • The function keys (F1, F2 ….F12) are used to perform specific functions by various application packages.
  • Cursor positioning and exit keys (e.g. Page-up, page -down, left, right, up, down, home, end, insert etc) are used to navigate and edit your work.
  • Numeric key pad (0…9) is used mainly for fast entry of numeric data.
  • The alphanumeric key used for normal operations.Special operation keys. (E.g. caps lock, shift, Alt, Control etc). Are used in combination with the other keys or on their own to perform a specific task. eg Shift and another letter will give a letter on the upper case.


  1. Output Devices

These are devices that enable the user to get the output from the computer.

The Monitor; It is a screen where the typed data appears. It’s also called Visual Display Unit (VDU)

  1. Printers; this is used to print records on the paper.
  2. Plotters; mainly used to print large architecture or engineering drawings.
  3. Speakers; Produces sound from the computer.
  4. Software; is a general term used to describe all the various programs that maybe used on a computer system.This program converts a general-purpose computer system into one capable of performing a multitude of specific functions.
Types of Softwares

There are two types of computer software;

  1. Application software
  2. System software
  3. Aplication Software (Packages); these are designed to meet a need for a particular application such as stock control or payroll management. They handle the need of the end user. They fall into two main categories;

a) Special purpose packages which are written to meet the specific need of an organization that cannot be satisfied by other sources of software.

b) General-purpose packages which may be used for a wide variety of purposes such as Wordprocessors, spreadsheets, database management systems, presentation packages, Graphics Packages, Computer Aided Design, Statistical analysis, etc.

  • Word Processors; Word processing describes the activity of writing with the aid of a computer. e.g., production of personal or business documentation such as letters, reports and memorandum, legal document, articles, books and even addressing of envelopes.


Features of a word processor
Word Processor Facilities
  1. a) Word wrap; as the text is typed, word moves automatically to the start of a new line, if there is no enough space at the right-hand margin.
  2. b) Scrolling; allow viewing of various parts of a document using scroll bars or navigation keys.
  3. c) Editing; User can delete unwanted text from the document.
  4. d) Spell checker; this facility identifies misspelled word that does not appear in its dictionary (stored on disk)
  5. e) Thesaurus; Allow the meaning of the words to be checked and suggests alternative
  6. f) Grammar checker; this identifies obvious errors and points out any grammatical constructions that it considers should be checked.
  7. g) Search and find; allows the user to search a document or a selected part of it for the occurrence of a particular character, word or sentence.
  8. h) Undo option; It’s used to reverse a mistake.
  9. i) Copying; to avoid repetition of re-typing the block of a text, to be used in another part of the document, the original can be copied.
  10. j) Cutting and pasting; Text can be transferred from one part of the document to another using this facility.
  11. k) Character formatting

Letters can be written in various formats and styles. E.g.

This is bold

This is italic

This is underline

This is strike trough

This is outline

  1. l) Mail merge; a facility that allows printing of multiple copies of the standard letter.

The most popular word-processor in use today is Ms-Word.

  1. Spread Sheets; This is an application (packages) used for manipulating figures. It consists of rows and columns. Mostly used spreadsheet package is Ms-Excel.


A sample of the spreadsheet

Database management system; Computer can help you store much more information in a much smaller space.T he application software that enables you to store information in a computer is called the Database Management System. It allows you to create lists of your information, analyze them, add new information, delete old info, etc. Mostly used packages are Dbase, FoxPro, Access, etc.


A sample of a Database


  • Presentation Packages; they are used to create outputs for presentation, which could be a sales presentation, management report, etc. They allow you to draw charts, graphs and other pictorial can also add text, scanned images, etc.

The most popular presentation packages include PowerPoint, CorelDRAW, etc

  • Graphics Packages; Desktop publishing is generally used in preparing newspaper layout, brochures, pamphlets, letterheads, books, and of graphics packages include; PageMaker & Ventura.

  • Computer Aided Design; mainly used in engineering design work and architectural drawings. The most popular of this software include Auto-Cad, Archi-cad, Artlantis, etc.
  • Internet Software. (E-Mail); Electronic-mail is a quick and cheap way of communication. All e-mail s/ware must have the basic capability of writing messages, sending and receiving e-mails and also features such as address book, mailing list etc.comonly used e-mail packages include internet explorer, Netscape mail, etc.
  • Statistical analysis; Numeric data is usually analyzed using numerical and statistical methods. Specials/wares have designed to perform this task. Once the data have been entered, the total, mean, mode, median, standard deviation can be easily computed. The most popular package for analyzing data is the Statistical and presentation software system (SPSS)


  1. System Software; this is programs that manage the performance of the computer itself. They are mainly supplied (installed) by computer manufacturers. They consist of operating systems, Assemblers, Compilers and system utilities.

Operating Systems Software; an operating system is a collection of programs that controls the operation of the computer hardware in the performance of routines such as the display of information on the screen or the movement of data between the internal memory and the processor.

Functions of the operating system

The operating system is a resource manager, as discussed below.

  • Memory Management; O/P keeps track of what parts of memory are in use and by whom and what parts are free.
  • Processor Management; A multi-user or multi-tasking computer system can be accessed by several users or application simultaneously.CPU can execute one program at a given time; therefore, access to the CPU must be controlled and monitored carefully.
  • Input/Output Device Management; Operating System monitors the use of each I/O device and signal any faulty detected and controls the allocation of functions to devices being used by the programs.
  • File Management; the O/P system keeps track of information, its allocation, use, status, etc. This collection is called a file system. It provides (O/P) the protection for data files and programs against any unauthorized access.

Types of the Operating Systems

There two main types of the operating system.

  1. a) Single stream; the system can handle one job at a time. eg Ms-Dos
  2. b) Multi-Tasking; this type of operating system allows a single user to process a number of tasks concurrently and transfer date between them. E.g Windows.


1.8 Revision question

  1. a) What’s a computer?

b) State and explain 4 roles of a computer in our society

c) Explain the following functions of a computer

  1. Input
  2. Output
  3. Processing
  4. Storage

d) Giving examples explain the following;

  1. Hardware
  2. Software
  3. Input devices
  4. Output devices

1.9 Summary

At this point, you have learned what the computer is, different parts of the computer, eg keyboard, mouse, monitor etc and various advantages and disadvantages the computers have in today’s generation. Different types of softwares eg application and system softwares have also been well explained so as to make you understand the way the computers work.