Classification of computers by size

Computers can be generally categorized into four, namely:

1. Super computers
2. Mainframe computers
3. Mini computers
4. Micro computers

SUPER COMPUTER

These are the largest, fastest and most expensive computers. The cost is several millions of dollars and the speed is between 600 million to 900 million instructions per second (MIP).

Another name for super computer is MONSTER. Scientists in weather forecasting, exploration make use of super computers. It can also be used for complex calculations e.g CRAY, X-MP etc.

MAINFRAME COMPUTERS

A mainframe computer is a large computer in terms of price, size of internal memory and speed. It has a variety of peripheral devices such as printers, plotters etc more than those found with small computers, except small computers with large amount of external storage.

Mainframe computers usually need a specialized environment to operate, with dust, temperature and humidity carefully controlled. They are used in large establishments e.g banks, airports etc. Examples of Mainframe computers are IBM 360/370,NCR-V 8800.

CONCLUSION

We learnt that computers are categorized into four which are: super computer, mainframe computer, minicomputer and microcomputer

EVALUATION

1. What is another name for super computer?
2. Mention TWO examples of mainframe computer.

MINI COMPUTERS

Mini computers were developed in the 1970s for specialized tasks (i.e they are special purpose computers). They are smaller and less powerful and less expensive than mainframes.

Mini computers, as they are called, are easier to install and operate e.g PDP  II, VAX 750/6000, NCR 9300, DEC, HP 3000 etc.

MICRO COMPUTERS

A microcomputer is a computer whose central processing unit (CPU) is based on a microprocessor.

Micro computers are at present the most popular of computers. They are very small. The capability is generally not as many and not as complex as mini computers or Mainframe computers.  They are easy to use. Another name for microcomputer is Personal Computer (PC).

REASONS WHY MICRO COMPUTERS ARE WIDELY USED

1. They are cheap.
2. They have small sizes.
3. They do not require special environment for their operations.
4. They can be used anywhere.

CONCLUSION

Microcomputers are the most popular and most widely used among the categories of computers. Another name for a microcomputer is Personal Computer (PC).

GENERAL EVALUATION

1. Mention four classifications of computers by size.
2. Differentiate between mini and microcomputers.
3. Give two examples of minicomputer.
4. Mainframe computers are used for …….

READING ASSIGNMENT

HiiT @ Schools for Senior Secondary Education Data Processing, pg14-15

WEEKEND ASSIGNMENT

1. The most popularly used categories of computers is ……

A.  microcomputer  B.  minicomputer   C.  super computer

2. Another name for microcomputer is……

A.   home computer   B.personal computer   C.  analogue computer.

3. HP 3000 is an example of……..computers.  A.  super   B.   mainframe   C.  mini.
4. Mini computers were developed in the …….A.  1970s   B.   1980s   C.   1990s.
5. Mainframe computers can be used in the …..A.   bank B. church C. market D. none

THEORY

1. a)  List any two examples of mini computers.

b) What is another name for microcomputers?

       2.    List any two reasons why micro computers are widely used.