JSS 2 WEEEK THREE FIRST TERM 2023 LESSON NOTE

 

Jss2

TOPIC: CLASIFICATION OF COMPUTERS BY TYPES AND SIZE

OBJECTIVE

At the end of this topic you should be able to:

1.       1.       List and explain the classification of computer by types

        2. List and explain the classification of computer by size

Introduction

Computer systems can be classified into their types namely:

        I.            Analog

     II.            Digital and

   III.            Hybrid

Analog Computers:

These computers have continuous valve. Example of analog computers include; fuel pump in filling station; volume control on TV set (since it allows one adjust the volume continuously in one sooth action), thermometer, speedometers in cars etc. the set of computers are represented in from of smooth curves and graphs from which information can be read, through the accuracy of the instrument depend on the reader. Analog computers operate by accepting data as quantity varying over length of time.

Digital computer:

They are used in industrial operations. The word “digital’’ means whole numbers (discrete) e.g. channel selector on the TV set is a digital device because it restricts one to discreate set of channels e.g. You can have 25, 2, 37 etc. but not channel 23-35 or 2.141 etc. Digital computers are more common computers. They operate with a set of instructions e.g. IBM 360/370 various IBM PC compatibility etc. Digital computers are more accurate than analog computers.

Hybrid computers

It combines some of the properties of both analog and digital computers. E.g. setting (i.e. their output can be in form of continuous or non-continuous valve or combination of both.

A vivid example of such combination can be seen in the setting of the TV.

1st – selection of a channel (channel)

2nd – Tune the channel until it receives the station you want clearly (analog)

3rd – storing the station on the channel (digital)

CLASSIFICATION OF COMPUTER BY SIZE

Hybrid computers are not too common, they operate in programmed from. Another example is robot used in industrial environment.

        I.            Mini computers

     II.            Micro computers

   III.            Mainframe computers

Mini computer

These set of computers were initially designed for scientific and special purpose but the usage has been extended to the business markets. These computers have the ability to perform many tasks at the same time. i.e. simultaneously. Examples are PDP II, VAX 6000, HEWLETT PACKARD 3000 etc.

Micro computers

Micro computers are the smallest and rugged general-purpose computers and most popular. It is single task oriented unlike the mini-computer that is many tasks oriented. It is very easy to operate and maintain. Examples are Apple Macintosh, IBM PC. Micro computers are of different shapes i.e. desktop, laptop etc.

Mainframe computer

Mainframe computers are large in terms of size of internal memory and speed of processing. They are used in specialized environments where dust, temperature and humidity are carefully controlled. It has large amount of external storage. The size of internal memory is usually more than 32 gigabytes of storage. They are mostly used in large establishments, banks, universities and research centers for processing large data.




Assessment

list 5 hybrid devices and state how they operate

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