On the basis of Working Principle

CLASSIFICATION OF COMPUTER ON THE BASIS OF WORKING PRINCIPLE

Computers are being very popular in the present days. In less than 100 years, computers have revolutionized much of human society. Modern computers have helped people in many ways, such as in communication, creating works, distribution of works, and so on. There are a number of computers that have fulfilled the necessities of the people.

On the basis of the application and working principle, the computers are classified as:

• Analog computer
• Digital computer 
• Hybrid computer

Analog Computer

The computer which operates on continuous data, usually of a physical nature such as length, voltage or current, etc. is known as the analog computer. An analog machine is usually a special purpose device that is dedicated to a single task. Analog computers are based on the analog signals that are continuous in nature.

Analog computers are widely used in scientific and industrial applications. It is used in hospitals to measure the size of the stone in kidney and mental disease diagnostics. It works by measuring rather than counting.

Analog computers are also called special purpose computers as they are usually used for scientific work rather than personal purpose. It is powerful in solving differential equations.

In comparison with digital computers, it has less storage capacity and their performance is less accurate. It is specially designed to perform continuously in physical forces like computing the temperature, pressure, and others. It represents physical quantities in the form of continuous waves.

Presley, thermometer, speedometer, barometer, lactometer, etc. are the example of an analog computer. Thermometer, barometer, speedometer, and ammeter are examples of analog devices.

Characteristics of Analog Computer

• The speed of an analog computer is fast but have no state.
• These computers work with physical values such as temperature, pressure etc.
• These computers are based on continuous data.
• These computers are not reliable and are difficult to use and operate.
• These computers are the base for digital computers.
• These computers have small memory.
• Normally, an analog computer cannot be reprogrammed.

Digital Computer

The computer which works on discrete data or discontinuous data is known as a digital computer. It works on a binary system where 0 represent off and 1 represents on. It is based on digital signals i.e discrete signals.

The basic principle of these computers is either present or absence of an electric pulse in the signals. It is a multipurpose and programmable computer. It is fast processing, more accurate and has a large memory capacity. It is usually a general purpose computer. Some examples of a digital computer are IBM PC, Apple/Macintosh computer, etc.

Characteristics of Digital Computer are:

• A digital computer operates by calculation.
• It is a multipurpose computer and can be reprogrammed.
• It has a large storage capacity than an analog computer.
• The results are accurate and high.
• It stores the data in the form of a bit.
• The processing speed is very fast.
• These machines are automatic.
• These computers are versatile in the sense that they can carry out the different type of jobs at a time without any interference.
• A computer works at the same speed, same accuracy, and with the same efficiency at all time.

Difference between Digital Computers and Analog Computers are:

Hybrid Computer

A computer, which is a combination of the best feature used in both analog and digital computers is called a hybrid computer. It helps the user to process discrete and continuous data. The hybrid computer can convert the analog signal into digital signals and digital signal into the analog signal. Hybrid computers are used mainly in specialized applications where both kinds of data need to be processed. Therefore, they help the user to process both continuous and discrete data.

They have the speed of digital computers and the accuracy of the analog computer. They can perform the task of both analog and the digital computer. They are usually used for special problems, as it is a special purpose computer in which input data are derived and measurement are converted into digits and processed by a computer.

Hybrid computers are used in the following fields:

• During rocket launching process, where the analog devices measure the speed of the rocket, temperature, pressure of the atmosphere, then, these measurements are converted into digital signals and supplied to the digital devices to analyze the data for taking appropriate steps on launching.

• In hospitals, analog components measure the temperature and blood pressure of a patient, then, these measurements are converted into a digital signal and fed to the digital devices that monitor the patient's vital information.

• In weather forecasting, analog devices measure wind speed, humidity, temperature, wind direction and fed to the digital devices that compare with the past information to predict the climate changes.

• In an automated industry, analog component measure temperature, pressure, speed and provide it to the digital component that takes proper action.

Characteristics of Hybrid Computer

• It is the combination of qualities of analog as well as a digital computer.
• It can process both continuous and discrete data.
• It is a special purpose computer.
• It can convert one type of data into another.
• It is mostly used in radar communication, rocket launching, weather forecasting and in other fields.
• It usually costs high compared to the analog and digital computer.
• Hybrid Machines are generally used in scientific applications or in controlling industrial processes.

(Dilli, 2015)

Bibliography

Dilli, S. P., Singh, k. E., Khadka, D., Bhatta, K. D., Baral, N., Saud, R. S., . . . Dangi, R. (2015). Fundamental of Computer Science. Kathmandu: KEC publication and Distribution.

Singh,Bikash Kumar et.al.Computer Science-XI,Aathari Publication Pvt.Ltd,ktm