Classifications of computer:

1. According to type of data processed
2. Based on purpose of use
3. According to size and efficiency

According to type of data processed:

Computers of this class can be divided into three categories......

 (i) Analog computer   (ii) Digital computer  (iii) Hybrid computer

classification-of-computer

Analog computer

Analogous signal (analogous mean equivalent) say any signals or waves that are always changing. So we can say any wave of analog if it changes continuously over the time.

That is to say, an analog computer is a computer which is used to measures continuous changing physical quantity and represents in numbers or any sign that is very understandable for human.

speedometer

Examples: voltage, temperature, pressure, height, light intensity, speedometer etc.

Digital computer

A digital computer is a electronics device which is take some data inputs(numbers, alphabet, symbol etc.) and read as binary form '0' or '1' only, after the processing resulted out  in discrete form.

It is different from analog which is discontinuous and analog is continuous like temperature.

tablet

Examples: Desktop, laptop, smartwatch, tablet etc.

Hybrid computer

Hybrid computers are computer compatible with both analog and digital type methods. Hybrid computer uses digital membranes to store intermediate results and uses analog device for mathematical calculation, counting etc. This type of computer can convert the signal analog to digital and digital to analog. Its speed is between analog and digital.

hybrid-computer

Examples: Hybrid computer used in hospital intensive care unit.
Portable computer like modern laptop can be detach keyboard and used as a tablet is a example of hybrid computer.

Based on purpose of use:

Computers of this class can be divided into two categories......

         (i) General purpose of computer

         (ii) Special purpose of computer

General purpose of computer

General purpose computer is able to solve mathematical and logical problems. This type of computer stores various types of programs and data for different purposes. We are normally use this type of computer. Ex. Personal computer.

Special purpose of computer

Special purpose computer design in such a way that they can perform special tasks. A set of instructions in this type of computer is inserted permanently.

Ex. Railway and airlines reservation system.

According to size and efficiency:

Computers of this class can be divided into four categories......

(i) Micro computer (ii) Mini computer (iii) Mainframe computer
(iv) Super computer

Micro computer

Micro computer size is the smallest, the lowest price, the storage capacity is relatively low and uses of peripheral devices less advantage. This type of computer used 8 to 32 bit microprocessor chip. To run this types of computer required less energy.

Ex. PC

Mini computer

Mini computer keeps its CPU, memory and storage unit on a row or rack. This a multi user computer system like mainframe. It is a medium size computer but bigger than micro computer. There is no need for special environment like mainframe. Storage Capacity is more than a micro computer. This types of computer used up to 32 bit microprocessor chip and it's processing speed 500 KIPS (Kilo Instruction Per Second). 

Ex. PDP-8, VAX 7500 etc.

Mainframe computer

The ability to store information on this type computer system is very high, can work on huge volume of data, and capable of solving complex scientific and mathematical problems, these types of computers are called mainframe computers. This is big size and so expensive computer system. This type of computer used 32 to 128 bit microprocessor chip and it's processing speed is so high about 100 MIPS (Million Instruction Per Second). It is a multi user computer system. This type of computer used in data processing center, engineering field and also used for scientific research.

mainframe-computer

Ex. IBM 4381, VAX 8000 etc.

Super computer

Super computer is a largest, high powerful and too much expensive computer system. Have maximum data storage capacity. This type of computer used 64 bit microprocessor chip and it's processing speed too high like mainframe 100 MIPS (Million Instruction Per Second). Super computer can used more than 150 user at a same time, so it is a multi user computer system. This type of computer used in space research center, robotics lab, big power hub center, bio-technology etc.

super-computer

Ex. PARAM, Cray etc.



Hope this helps!

Thanks!