According to signal used by computers computers are two types:-
1] Analog Computer:-
An analog computer is that which uses analog signal as input, It uses an infinite number of voltage or current values. Characteristics of a analog computer are:-
– It operates by measuring.
– It require physical analog values.
– It functions on continuous varying quantities.
– The output is usually represented in the form of graph.
– The accuracy of output is poor.
– It has limited memory space.
– The speed of analog computer is low.
– It has limited application.
2] Digital Computer:-
Digital computers are those which operate on discrete quantities. Computers uses binary code 0 and 1s to represent the information. All information added to the computer as an input are converted to 0 and 1.
According to usage, computers are two types
1] General Purpose Computer:-
Mini computers work same as micro-computers and mainframe computers, only the size of computer is small. They are as powerful as micro-computer which are designed to place in a small place and can be carried easily anywhere. They can be useful for processing data in the field of business and industry. They support high level languages such as C, C++, Java etc.
Characteristics:
– It is general purpose machine which is smaller than mainframe computer.
– Its storage capacity is about 2 megawords.
– Its word length are 12, 16, 24 & 32 bits.
– Its rate of acceptance and transfer of data is maximum of 4 millions bytes/second.
– It support high level languages.
3] Mainframe Computer
A very large size computer capable of supporting hundred of users at a time and which has large storage capacity with faster processing capacity is mainframe computer. Mainframe computers are sophisticated machines designed for manipulating millions of instructions by hundreds of users at same time. They are specially used in Europe and America by hospitals, insurance companies, banks where numbers of users are served.
Characteristics:-
– It is the largest computer in general purpose computer.
– It can support hundreds of users at same time.
– It is more powerful in computing than server computers.
– It has large storage capacity than other computers.
– It is used for multi-tasking, multi-user purposes.
4] Micro-Computers
Micro computers are small size and general purpose computers, which are used in business, education, entertainment, medical and industrial purposes. Since a micro-processor (processor) is used in it. Micro-computer is named after it. It is used for multi-tasking, multi-user but for limited resources. It accept high level languages.
Characteristics:
– It is small size computer which has low storage capacity.
– Its processing speed is limited.
– It can process text, graphics, video etc.
– It support high level language.
– It can support word length of 16, 32, 64 bits.