What are the Various Classifications of Computer
COMPUTERS are classified according to the data they process. Generally computers are classified into FOUR categories namely
1. Analog Computers
2. Digital Computers
3. Hybrid Computers
4. General Purpose Computers
Analog Computers – Analog computers are those computers which are used to measure continues type of data. These computers are primarily used where there is need for regular measurement. The best example of an Analog computer is the Speedometer that is present in our scooter, which is used to measure the speed.
Digital Computers – Digital computers are those computers which represent data in terms of discrete numbers. These computers are used where calculations are to be done. These computers can perform calculative as well as logical functions. These computers are primarily used for data manipulation and storage.
Hybrid Computers – Hybrid computers combine the features of both Analog and Digital computers. These computers perform both the functions of a Analog and a Digital computer. These computers are primarily used in space programmes, hospitals and military services. As in hospitals heartbeat is measured by the analog computer and the signals are fed into digital computer which convert them into digital data signals and then displayed on the monitor.
General Purpose Computers – These are those computers which are designed to solve a wide variety problems. Most of the digital computers are General Purpose Computers. General Purpose Computers are further classified according to their size and capability namely
1. Mainframe Computers
2. Mini Computers
3. Micro Computers
4. Personal Computers
Mainframe Computer – Mainframe computers are the logical decendents of the early computers. As the technology advanced their speed and their cost performance ratio improved. These computers are used where large amount of data is to manipulated and stored. Such machines are used in Large computer centers, Banks, Insureance companies and large organisations.
Mini Computers – These computers are smaller in size than the Mainframe computers. These machines were designed to operate in unprotected environments and to offer high reliamility. The main advantage of Mini computer is their low cost and high reliability. Their processing speed is greater than the Main frame computers . These machines are used in shops, homes and small business establishments.
Micro Computers – Micro computers came into existence with the breakthrough of microprocessor chip. The heart of a Micro computer is the microprocessor chip that controls all the input and output functions. Micro computers were very much fast in their performance. Their speed and reliability was more than Main frame computers. These types of computers were very much popular in the Mid Eighties, even now these computers are in use.
Personal Computers – Personal computer is a general purpose Micro computer system that executes program instructions to perform a wide variety of functions. It is designed to be operated by one user possesing very little, if any, programming language. But it also serves the needs of a non-programmer. By Personal we mean that we can run a variety of softwares for our own gains and equally important is whether the machine is dedicated to an individual, thus becoming that individuals ‘Personal Computers’. Personal Computers come in different configurations depending upon their speed, storage and microprocessor. IBM introduced a complete Personal Computer on Tuesday, Aug 11 1981, since that time, IBM has sold more than 10 million PC’s. The different models of PC’s are
PC/XT – PC/XT stands for Personal Computer with Extended Technology. The basic configuration of these computers is
-640 K RAM
-10-12 Mhz speed
-Floppy drive present
-20-40 Mb hard disk
PC/AT 286 – PC/AT stands for Personal Computer with Advanced Technology. The basic configuration of these computers is
-1 Mb RAM
-25-33 Mhz speed
– Floppy drive present
-40-120 Mb hard disk
PC/AT 386 – The basic configuration of these computers is
-1-4 Mb RAM
-33-40 Mhz speed
-Floppy drive present
-120-360 Mb hard disk
PC/AT 486 – The basic configuration of these computers is
-4-8 Mb RAM
-40-66 Mhz speed
-Floppy drive present
-Upto 540 Mb hard disk