Development of Computers

Development of Computers The earliest known device to record computations was the abacus. It dates back to ancient times and was invented by the Chinese. Ten beads were strung onto wires attached to a frame. Addition and subtraction were read from the final positions of the beads. It was considered the first manual tool used in calculating answers to problems that provided information and in a primitive way storing the results. Abacus Mechanical Clock During the Middle Ages the first closed system in terms of calculating information was invented by use of a mechanical clock. The parts of the clock calculated the time of day. The time was displayed through the position of two hands on its face. The inventor pre-programmed the clock instructions through the manner in which the pull of the weights and the swing of the pendulum with the movement of the gears established the position of the hands on the clock face. Mathematics John Napier (Scotsman mid 1600s) discovered logarith

Definition of a computer

Definition of a computer

Lesson Objectives:

at the end of this lesson, the learner should be able to describe:
  1. definition of a computer 
  2. parts of a computer
  3. peripheral devices
  4. functions of a computer
  5. characteristics/features of a computer
  6. advantages of a computer
  7. purpose of a computer
  8. basic terms used in computers

In simple terms a computer is a machine that processes data into information

A computer can also be described as an electronic device that saves, transmits and processes data into information using electrical signals.
The physical parts of a computer include:

  1. Mouse, 
  2. Keyboard, 
  3. system unit and 
  4. screen.

Which part of a computer is missing in the image above?

Common terminologies used in computer

functions of a computer
Computer functions


data simply refers to raw alphanumeric values which have no much meaning to the user.
//raw here stands for unprocessed


information is a sequence of numbers and characters which can be interpreted as having meaning. Information can also be described as processed data

A computer Program

a computer program is a sequence of instructions written to perform a specified task with a computer.

Input stage

this stage involves entering data into the computer using input devices i.e. keyboard


this stage involves manipulating of data using processing devices i.e. the CPU

Output stage

this stage involves the processing outcome that will be displayed by output devices i.e. the screen

Parts of a computer

System Unit –this part consists of the CPU and the Motherboard. It also houses drives (used to read/write disks) and cards (used to support peripheral devices).
//many students confuse between the CPU and the system Unit. either way a CPU is a processing gadget housed inside the system unit and the system unit is a combination of electronic gadget attached together in a box like cage these devices include: Drives, Mother Board (System Board), Cards i.e VGA, CPU, Ports e.t.c
The CPU works with the help of the mother board and other devices like the Hard disk drive and the random access memory to process and store information. Attached on the motherboard are devices like Resistors, Capacitors, inductors, integrated circuits, transducers and so much more.

Peripheral Devices

these are devices connected to the system unit via communication media i.e. interface cables and wireless means. The cables are attached to the system unit using special sockets called ports, while wireless peripheral devices use light rays (optical means)and magnetic spectrum to connect to the system unit i.e. infrared rays.

Examples of peripheral devices

Keyboard- this peripheral device looks like a typewriter. It is used to enter data into the computer in form of characters, symbols and instructions. Therefore, the keyboard is an input device.
Monitor- the monitor is also called screen or visual display unit (VDU). This output device enables the user to see what is happening in the system unit.
Mouse- this is a pointing device that enable the user to enter commands in a computer. To input a command, the user moves the mouse which also moves the pointer on the screen. The pointer is then clicked on icons and controls to issue commands.
Printer- this is an output device which converts soft copy (intangible data) into hard copy (tangible data).
Modem- the word modem is derived from modulation (converting a digital signal to analogue) and demodulation (converting an analogue signal into digital). This device connects the computer user to the Internet. It can be used as either an input or output device.

Functions of a computer:

functions of a computer are mistakenly taken to be the purpose of a computer. Whenever we talk of functions, we normally mean the activities involved in the operations of a computer. There are three main activities involved.
The three main activities involved in the operation of a computer include:
  1. Input;
    this is the ability of a computer to accept a task through input devices such as a keyboard.
  2. Processing;
    processing is an activity that addresses the conversion of data into information.
  3. Output.
    this is an activity which ensures the computer displays the results of a processing activity.
other scholars include 'storage' as another activity, however storage can also be categorized in the activity of processing. leaving us with three fundamental functions of a computer as described above.

Purpose of a computer

The purpose of a computer implies the objectives of a computer. To answer this effectively, we must first recognize a computer as a machine. Rather than being a machine it is very effective, accurate, automated and reliable. 
Therefore, the main purpose of a computer is 'to accomplish a task with the computer user'.

Characteristics of a computer

Characteristics here simply means behavior of a computer or attributes of a computer. These are features of a computer that ascribe to its uniqueness as compared to other objects of similar aspects.
These characteristics include:
  1. accuracy
    computers are ultra-accurate as compared to other machines and people
  2. diligence
    computers can work for many hours without complaining nor alter ability to make or not make errors
  3. storage
    computers have the ability to store lots of information
  4. versatility
    computers have the ability to multi-task (process many activities at the same time)
  5. speed
    computers process information very fast
  6. memory
    computers have the attributes of recalling/remembering previous events and they recall very fast
  7. programmable
    computers can function if and only if they are programmable.
  8. electrically powered
    another attribute for all computers is that they cannot function without being powered by electrical signals either through mains supply or batteries.

Advantages of computers

Computers have more advantages than disadvantages. They include:
  1. make work easier (all machines make work easier)
  2. they are accurate
  3. they are efficient
  4. they are reliable
  5. they can work in hazardous places
  6. they store a lot of  information
  7. they increase productivity
  8. they are automated
  9. saves time
  10. they entertain
  11. they can be reprogrammed to fit user needs
  12. consumes less power
  13. cheap to acquire (such as micro-computers)
  14. fast processing speeds
  15. makes communication easier, faster and efficient

Related Videos

Related questions on topic:

  1. define a computer
  2. what are peripheral devices?
    1. state any five peripheral devices
  3. state any three functions of a computer
  4. state the four main parts of a computer
  5. define the following terms:
    1. information
    2. data
    3. computer program

Next topic: Development of Computers


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