WHAT IS COMPUTER???

computer is an electronic device operating under the control of instructions stored in its own memory that accepts data
, process the data , produce results and stores the results for future use.


CATEGORY OF COMPUTERS


WHAT IS?

1}SUPERCOMPUTER
A supercomputer is the fastest , most powerful , most expensive computer and used for very complex , sophisticated job such as nuclear energy research , weather forecasting , petroleum exploration , online banking , automotive design.



PHYSICAL SIZE 
Full room of equipment 

SPEED
Capable of processing many trillions of instructions in a second.

STORAGE
Can store more than 20,000 times the data and information  of an average desktop computer.

2}MAINFRAME
A mainframe is a large , expensive , powerful computer that can handle hundreds or thousands of connected users simultaneously [multi-user]
Mainframe often used in businesses that manage large amounts of data,for example ,insurance companies use mainframes to process information about millions of policyholders




PHYSICAL SIZE 
Partial room to a full room of equipment.

SPEED
Capable of processing millions of instructions in a second 

STORAGE
Can store tremendous amounts of data , instructions and information, enterprises are able to bill millions of customers , prepare payroll for a thousands of employees , and manage millions of items in inventory.

3}PERSONAL COMPUTER
Is a computer that can perform all its input , processing , output and storage activities by itself and is intended to be used by one person person at a time.



2 types of PC
>Desktop.
>Laptops


PHYSICAL SIZE
Fits on a desk,lap


SPEED
Various , depending on the memory and processors


STORAGE
Various , depending on the size of a hand drive