Classification of Computers – JSS1 Computer Hardware & GSM Repair Lesson Note (Second Term)

Classification of computers is the grouping of computers by how they work, how big they are and what they are used for.

Behavioural objectives

1. State the three ways of classifying computers.
2. Name and describe analogue, digital and hybrid computers, with one example each.
3. Name and describe micro, mini, mainframe and super computers, with their uses.
4. Explain the difference between general-purpose and special-purpose computers.
5. Explain why we need different types of computers.

How are computers classified?

Computers are classified in three main ways: by data handling, by size and by purpose.

• By data handling: the kind of data the computer processes (analogue, digital or hybrid).
• By size: how big, fast and powerful the computer is (micro, mini, mainframe or super).
• By purpose: the range of jobs the computer was built to do (general or special).

What are the types of computers by data handling?

There are three types of computers by data handling: analogue, digital and hybrid.

Analogue computers

• Meaning: they measure things that change constantly, such as speed, temperature or pressure.
• Output: they show results on a needle or a scale, not as exact numbers.
• Examples: a car speedometer with a needle, and a traditional thermometer.

Digital computers

• Meaning: they process data as digits, 0 and 1.
• Features: they are very exact and are the most common type in use.
• Uses: typing, calculations, games and browsing.
• Examples: laptop, smartphone and calculator.

Hybrid computers

• Meaning: they combine the features of analogue and digital computers.
• Features: they have the speed of analogue and the accuracy of digital.
• Where used: special places such as hospitals and big factories.
• Example: the hospital machine that monitors a patient’s heartbeat (ECG).

What are the types of computers by size?

There are four types of computers by size: micro, mini, mainframe and super computers.

Micro-computers

• Meaning: the smallest and most common computers, made for one user at a time.
• Examples: laptops, tablets and desktop PCs.

Mini-computers

• Meaning: medium-sized computers, more powerful than micro-computers.
• Uses: small companies use them to connect many people together.

Mainframe computers

• Meaning: very large and powerful computers that serve thousands of users at the same time.
• Uses: banks keep records of customers’ money, and airlines book flights.

Super-computers

• Meaning: the fastest and most expensive computers in the world.
• Uses: very hard jobs such as weather forecasting and space research.

What are the types of computers by purpose?

There are two types of computers by purpose: general-purpose and special-purpose computers.

• General-purpose computers: they do many different jobs, such as typing, games and calculations. Examples are laptops and desktop PCs.
• Special-purpose computers: they are built to do one job only. Examples are the computer in an ATM, a washing machine or an ECG machine.

Why do we have so many types of computers?

We have many types because different jobs need computers of different size, speed and power.

• Micro-computers: they are portable and easy to use for daily life.
• Mainframes and super-computers: some jobs, such as tracking every bank account in Nigeria, are too big for a normal laptop.
• Wrong size: carrying a super-computer in your school bag to work out 2 + 2 would be impossible.
• Most common: most computers around you today are digital micro-computers.

Evaluation

1. Name the three ways of classifying computers.
2. Which type of computer would a scientist use to study a rocket launch?
3. Is your mobile phone a digital or an analogue computer? Give a reason.
4. Name one place where you might find a hybrid computer.
5. State one difference between a general-purpose and a special-purpose computer.

Assignment

Draw a table with three columns: type of computer, size and one use. Fill in micro, mini, mainframe and super computers in your notebook.