What is Computer System?

Where we are talking about computer system? A computer is an electronic device that can be programmed to accept data (input), process it and generate result (output). A computer along with additional hardware and software together is known as a computer system.

Understanding a Computer System

  1. What is a Computer System?
  2. Characteristics of Computer
  3. Generation of Computers
  4. Types of Computers
  5. Basic Ideas and Terms

What is Computer System?

A computer can simply be defined as a machine that is used to generate some kind of information from the data that is fed into the computer.

The computer consist of a set of hardware which when coupled with a program, can be turned into a tool for some specific purpose. The hardware refers to various components such as the input and output devices, memory, storage, processor etc.

A computer system is set of central processing unit (CPU), memory, input/output devices and storage devices. All these components function together as a single unit to deliver the desired output.

Characteristic of Computer

Speed: Computer makes calculation very fast rate. The present computer can do (30 million calculation in one second) without any mistake.

Storage Capacity: A computer, system can store great amount of information in the order of Giga byte and call back any data out of its stores memory in a few Nanosecond.

Accuracy: Computer works on the basis of electric pulses, where there is no chance of making mistake. Mostly errors are due to wrong feeding by the users.

Versatility: Computer can perform each job effectively without being tired.

Generation of Computers

Computer production started in the 1940s when the first electronic computer was created. Since then, the improvements and enhancement in the field of electronics had considerable influence on the design of computers thus leading to what is known today as Generation of computers.

  • First Generation

Dr. john Vincent Atnasoff and Clifford Berry created the first electronic computer. The ABC used vacuum tubes for storage and arithmetic and logical functions. This work was noticed by John W. Mauchly, who in 1940-41 teamed up with J. Presper Eckert Jr, and organized the construction of the ENIAC(Electronic Numerical Integrator and Calculator). The first general-purpose computer was ENIAC to be put fully in operation.

Using vacuum tubes the ENIAC could perform 300 multiplication per second. However, the fact that it weighed 30 tons and occupied the space of three bedroom house was the major disadvantage of this computer.

This idea was incorporated into a new computer called the EDVAC(Electronic Discrete Variable Automatic Computer). Later in time, the UNIVAC(Universal Automatic Computer) come into existence.

  • Second Generation

The main disadvantage of the first generation computers was the fact that the vacuum tubes, owing to their short life, had to be replaced frequently and they generated a lot of heat. these computers took up a jot of space and programming them was a tedious task because programs had to be written in machine language.

The computer in this generation used solid state components such as the Transistor developed by the Bell Laboratories some computers of this generation are LEO mark lll, ATLAS and the IBM 7000 series.

  • Third Generation

The second-generation computers were to do either scientific or non-scientific applications but not both. Thus in 1964, IBM announced the IBM 360 family of mainframes, where each processor had a set of large built-in instructions,

The computers in this generation used the technology of integrated Circuits (IC). Since the ICs were small in size, there was a further reduction in size of these computers.

  • Fourth Generation

As the technology advanced, the size of the ICs reduced and more and more components could be packed into smaller chips. They were called Large Scale Integration (LSI) and Very Large Scale Integration (VLSI) chip. Since the computers in this generation used these chips, their size was greatly reduced at when operated the speed increased and they cost decreased. The computers of today are said to be of the fourth generation.

  • Fifth Generation

It is predicated that by early 21st century. computers will be able to behave like human making interaction more human like. They would be able to think and act on their own. This situation is very well depicted in the movie Terminator ll where the computers acts on their own based on their own judgment.

Types of Computers-

Depending upon the internal structure, feature and applicability, Computer can be categorized based on their size and design.

Micro Computer

Modern computer can vary in size ranging from the one that fills the entire room to a size that is small enough to fill the nail of your thumb with room to spare, storage, cost and the ability to handle number of peripheral devices. The difference in size also varies the number of users that can work on the system simultaneously. At the lowest end of the size scale is the microcomputer. They are small devices that can be used to perform dedicated tasks like scanning the code of a can of juice. The more familiar computer is a kind of a microcomputer.

Mini Computer

The mini computer are also small general purpose computer having the capability to server a number of users simultaneously. They generally more powerful and expensive than the microcomputers. In size, they range from desktops to a size of a small file cabinet.

Mainframe computer

The mainframe computer are much bigger in size and offer very high processing speed and storage capacity.

Super computer

Finally the supercomputer that are the fastest and most expensive system in the world they are typically used for complex scientific operations like weather forecasting, statistical analysis etc.

Basic Ideas and Terms

  • Data

Data is a name given to the fact that are supplied to the computer. It is then processed to obtain the desired output. In simply terms, data can be defined as the raw from of information.

As an example, in the operation to add two number A and B the values A, B and the add operator (+) is data.

  • Program

We know that the computer is a digital devices. It is thus capable to understand the digital signals. These signals are generated based on certain instruction that the user feeds into the computer.

A simple example of a program to add two number is as given below;

Input A

Input B

Add A to B

Assign value to C

In the steps given above, Input asks the user to value of A and B. The computer then adds the value of A to the value of B and assigns the results to C. These four instructions are collectively called a program.


Information can be termed as a more useful and intelligible from of data. A program operates on the data in a specified format and transforms it into iinformation.

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