Types of Computer

The computer is defined in many different words; a few definitions are listed below.

a)     Computer is a machine that accepts input data, processes it and gives output.

b)    A computer is a device capable of accepting data, applying described processing to data and supplying results of these processes.

c)     Computer is an automatic electronic calculating device which can process given data in the pro-defined manner and produce desired results.

d)    An electronic computational device having internal storage, a stored program of instructions and capability for modification of the set of instructions at any time, is known as computer.

e)     Computer is an automatic electronic device. It can receive data from many input devices. Computer processes this inputted data with the help of a stored program at high speed and accuracy. After the desired processing of data, results may be received of differed output devices.

COMPUTER VERSUS CALCULATORS

A computer is an electronic device which helps to solve problems and data. This definition may also be applied for simple calculators, but there are three major differences between computer and calculator as described below.

INTERNAL STORAGE (MEMORY):

The computers have internal storage called memory, for storing programs and data. Now a day some calculators also have memory, but this memory is very small as compared to computer’s memory and that is not much capable as computer’s memory.

PRE-DEFINED INSTRUCTIONS (PROGRAM):

Even though, calculators have some pre-defined formula, but they do not contain any type of program. In computer a set of instructions (program) can be stored in memory.

ALPHABETIC DATA:

A computer has an ability to operate alphabetic data which may have a number of special characters. In other hand calculators can only operate on numeric data.

ADVANTAGES OF COMPUTER

SPEED:

The most important advantages of computer over human being are the speed, with which it performs instructions. An older computer is capable of performing several thousand instructions per second.

ACCURACY:

The results of computer are much accurate than manual work.

DILIGENCE:

Another advantage of computer is to perform repetitive jobs diligently. It means that computer is never bored with repetitive jobs.

RUN FOR LONG PERIOD:

A computer can operate without failure for long period of  time, while a human has to be exhausted after a certain period of time.

VARIETY OF TASKS:

The computer is capable of performing a wide variety of tasks. Thus a computer could be useful at same time to people from all together different fields.

AUTOMATIC OPERATION:

Computer can perform any number of operations in automatic mode. The sequence of these operations is stored in memory as a program.

DECISION MAKING CAPABILITY:

It is true that, the computer can not think, but a computer can take simple decision. Such as 50 is greater then 30 or not.

LIMITATIONS OF COMPUTER

INFLEXIBLE:

The computer are not flexible. For example to a human being “addition of two number”, or “totaling of two number” means one and same thing. But computer in not so smart, it understands only the symbol “+” and nothing else.

NEED DETAILS:

The computer needs very detailed instructions. It means that each step must be instructed to perform, even it is very little and ignorable for human being.

EXPENSIVE EQUIPMENT AND MAINTENANCE:

The computer and their devices are much expensive than the equipment required for manual work. In the same way maintenance of these equipment is very costly.

MORE STAFF:

It is required to appoint computer personal to operate computers. It increases the expenses of organization.

LOSS OF DATA:

In particular circumstances, stored data may be completely lost. It could be impossible recover. Therefore backup copies of latest data must be maintained.

CLASSIFICATION OF COMPUTERS BY SIZE

1.     Microcomputers

2.     Minicomputers

3.     Macro or Mainframe computers

4.     Super computers

5.     Laptop computers

MICRO COMPUTER:

Micro computer are very small machines, lower in price, easy to operate and as they are cheaper there is not much difficulty in maintenance. Micro computers, although provide a lot of facilities available in macros and minis, but can not compete them. However these computers are used in small business applications and for home computing.

MINI COMPUTER:

The mini computers are very popular in time-sharing requirements. In time sharing environment many users can utilize a single computer at the same time by attaching terminals to it. These computers are also found in laboratories for all types of scientific and engineering work.

MACRO COMPUTER:

The large size computers including all peripherals and attached equipment are termed as “macro” computers or “mainframe” computers. A mainframe computer might support thousands of users, such as a worldwide airline reservation system.

SUPER COMPUTERS:

Very big computers used for complex scientific calculations are called super computers. These are the most costly computers. Super computers are used in nuclear physics research, experimental oil fields, weather forecasting, satellite controlling, space shuttle launching, etc.

LAPTOP COMPUTER:

The smallest computers in size have been developed. These types of small computers look like an office brief case and are called “Laptop” computer. The laptops are also termed as “Portable computers”. Due to the small size and light weight, they become popular among the computer users.   

TYPES OF COMPUTERS ACCORDING TO FUNCTIONS 

1.     ANALOG COMPUTER

2.     DIGITAL COMPUTER

3.     HYBRID COMPUTER

ANALOG COMPUTER:

Analog computers are measuring devices. They are used to measure only the continuously variable quantities such as temperature, pressure, distance, velocity etc. Analog computer device the data from some form of measurement. Analog processor is used in petrol pump, thermometer, speedometer, blood pressure measuring apparatus, voltmeter and ammeter are the example of analog computers. They are used in scientific applications.

DIGITAL COMPUTER:

Computers operate on representation of real numbers or other characters coded numerically are termed are digital computers. The digital computer has memory and solve problems by counting precisely, adding, subtracting, multiplying, dividing and comparing. The ability of digital computers is to handle alphabetic and numeric data with precision and speed. It makes them best suited for business applications.

HYBRID COMPUTER:

Hybrid computers have characteristics of both analog and digital computers. These computers are equipped with special conversion devices. They have speed of analog computer, while accuracy of digital computers.

                                         

                                                           

DIFFERENCE BETWEEN ANALOG COMPUTER AND DIGITAL COMPUTER