Types of computers

Computers can be classified on the basis of size, work, brand and model. So, we can classify computers in following ways:

On the basis of size:

i) Super computers

ii) mainframe computers

iii) Mini computers

iv) micro computers

Super computers:- Super computers are most powerful and most expensive computer and the processing speed is at least 10 times greater than other computers. They have large storage capacities as memory devices. It is big machine. inside the super computer, there are

several smaller computers each of which can work a difficult parts os a work. The super computers are mostly used in weather forecasting , nuclear science research centers, medicine, for creating computer graphics, etc. It can calculare about 400 million numbers per second. Some examples of super computer are:-CRAY,

NEC SUPER SXII, CYBER 205, CDC- STAR100,etc.

Mainframe computers:- The mainframe computers are also big in size and more powerful and high storage capacity. the mainframe computers have more than 100 terminals points. it is general purpose computing system. some examples of mainframe computers are:-IBM 1401, ICL 2950/10.

a) The major characteristics of mainframe computers are:-

b) Used more than 100 terminals.

c) Central processor/central administration.

d) Used in big organization, industrial forms, or government for large scale data processing.

Mini computers:- The mini computers are similar to mainframe computers but they are comparatively smaller, less expensive, less powerful, less storage capacities as memory. These computers are like a small mainframe computers. some examples of these computers are Prime 9755, Van 39,etc. it could perform its operation at 4 million

bytes per second.

the major characteristics of mini computers :-

a) Medium in size(10 sq. feet) and cased for general purpose.

c) Support more than 50 terminals.

c)Used in medium sized organization and corporation for their database adminstration.

Micro computers:- The micro computers are smallest general purpose computers. These computers are called micro because microprocessor is used and they are very small in size. It is called PC(personnel computer) as they are mostly used at a time or at home computers because os its popularity at homes. these computers are used in different fields like colleges,

schools, banks, hospitals, offices, entertainment or others. The different types of computers of this category are laptop computers, palmtop computer, notebook computer. The size of computer reducing day by day. some examples are:- IBM pentium PC, Apple/MAcintosk, DELL, Compaq, etc.

The major characteristics of these computers:-

a) Smallest in size among all types of computers.

b) Cost and power consumption is reduced.

c) Used for general purpose.

d) A single user computer.

e) Used in different field as banks, offices, colleges, etc.

On the basis od work(application)

the computers are classified into three categories on the basis of work. they are:-

i) Analog computer

ii) Digital computer

iii) Hybrid computer

Analog computer:- The computers which work with natural phenomena or physical values like frequency, earthquake, volcano, current flow, water flow, pressure, temperature, etc. are known as Analog computers. They are used for scientific purposes but not used for commercial or general purposes. the main advantages of these computers are that the calculation take place in parallel processing and these are faster. eg:- "plesly", analog devices, like speedometer, thermometer, sesmograph,etc.

The main characteristics of analog computers:-

a) Based on continues data.

b) Measuring only physical or natural phenomena.

c) Used for scientific purpose.

d) Generally, ir has no storage capacity because it works real time process.

e) The accuracy of analog computers is very poor compared to digital computers.

f) Output of analog signals are not known by general person because analog signals are in form of wave lines, curved lines or bar graph.

Digital computers:- The computers which work upon the discontinious data is known as digital computer.They convert the data into digits(binary digit-'1' & '0').They count the data rather than measuring process. eg:- IBMPC, Apple macintosh computer, DELL, etc.

the type of digital computers are used for commercial and general purpose.

their are two types of digital computers:-

a) special purpose computer

b) general purpose computer

General purpose computer:- These computers are mainly used in general purposed. They are mostly used in different fields like schools, colleges, banks , offices, home, entertainment, etc.

Special purpose computers:- These computers are designed for special purpose. They are mainly used in weather forecasting,molitary weapons systen,airlines reservation, processing system, banks cheque processing system.

The main features of digital computers are as follows:

a) Based upon the discrete data that is not continious data with time.

b) Counting process is used rather than measuring process.

c) Used for commercially and general purpose.

d) The accuracy of digital computer is very high compared to analog computer.

e) It is multiporpose and multiprogrammable computer. so, it's cost is high.

f) The digital computer has large storage capacity because it is used to store the data internally for use and reprogramming.

g) Digital signal of electrical pulses.

Hybrid computer:- Hybrid means the combination of two types of computer. So it is combination of analog computer and digital computer. It can perform the data or information as discrete data and continious data. it has capacity to control the analog data into digital data and vice versa. hybrid computers are mostly used in hospitals(intensive care unit)[ICU]. computers are also used in jet planes. Hybrid computers are also used for weather forecasting.

The main features of these computers are:-

a) Combination of analog and digital computer.

b) Accepts both types of data i.e. comrinious as wekk as discrete data.

c) Capacity to convert analog data into digital data and digital data into analog data.

d) Mostly used in hospital ICU, jet planes, etc.

On the basis of brands:

Computers are mainly classified into two grous on the basis if brand.they are:

I) IBM computers

a) IBM PC

b) IBM compatible

ii) Apple/ Macintosh computer

IBM Computer:- IBM company was established by Dr. herman Hollerith in 1932 A.D. is a world's largest manufacturing company till today. In the beginning IBM maufactured 'mainframe computers', then 'mini' computers and now micro computers. It uses processors, multimedia devices and some hardware ports which is developed by other companies like 'Intel' and uses the principle of its own. so, computer which is developed by IBM company is called IBM computer.

Types of IBM computer

There are two types of IBM computer, they are:

i) IBM PC & ii) IBM Compatible

The computer developed by IBM company itself is called IBM PC. The computer which is manufactured by using the ports of some other company and the principle of IBM PC is called as IBM compatible is also termed as duplicate of IBM PC which is totally similar to IBM PC.

Apple/ Macintosh computer:- The computer which is manufactured by Apple/Macintosh company with its own specific architecture is called Apple/Macintosh computer. The Apple company was established in 1970A.D. The Apple company is totally different from IBM computer with respect to hardware parts as well as software also. Software made for IBM computer can't fit for Apple comuter and vice versa. The hard disk & floppt disk formatted by one can't be recognised by other computers.

On the basis of model

The computer can be classified into three categories on the basis of its model. They are:-

i) XT computer(extra/ extended technology)

ii) AI computer(Advanced technology)

iii) PS/2 computer(personal system-2)

XT computer:- XT computer are the old technology based computer with slower spped more than 4.77 MHz. This type of computer can only support the tent based operating system on software but can't support the GUI(Graphical User interface). software like windows,Linux, Unix, etc. This type of computers had processors like 8080, 8086, 8088 with 4-bit dara word length. the complex mathematics and data word length. The computer mathematics and long processing couldn't be done by this computer. the I/O devices were also not flexible, interactive and faster.

AT Computers:- AT computers are advanced technology based computers. they have faster processing speed more than2GHz and can support the coth operating system or software either GUI bassed or text based. these types of computers have processors like 80286, 80386, 80486, Pentium 1, Pentium 2, Pentium 3, Pentium 4,etc. Any type of computer problem can be done with long processing time. The I/O devices are more flexible, interactive and faster than XT computers. The co-processor can be used to kelp the main memory to perform the calculations.

PS/2 computer:- PS/2 computers are not totally differnt model but are modified computer of AT computers. These computers wer built after 1990.PS/2 computers contain laptop computer, palmyop computer, notebook computer. The rechargable and battery operated with very fast I/O devices. OS/2 software was used at beginning but now a days windows is used. It works like almost all AT type of computer.