With the advancement of the technology, computer has become a convenient tool for everyone. Once, man used to process data using a pen, pencil or other devices. But today the computer has become man’s data processor and it is an indispensable tool for him. So let’s analyze the fundamentals of a computer system in depth.

What is a computer ?

A computer is an electronic device which accepts or collects data, processes them according to the given instructions and produces the desired output. In addition, we can call the computer as an ‘ Information System’.

Features of a computer

The characteristics of computers that have made them so powerful and universally useful are given below. Let’s discuss them briefly.

Speed

 

A computer takes only a few seconds to perform calculations. It executes more than one million instructions per second.

Accuracy

A computer provides correct output when it receives correct instructions and data.

Efficiency

A computer never gets tired. In other words, it can work round the clock with the same level of accuracy.

Versatility

We can use a computer to perform many tasks simultaneously. This is one of the special features of a computer.

Storing and Retrieving

A computer stores large number of data and information in a relatively small unit and we can retrieve them easily and quickly when needed.

Classification of computers

As described above a computer can perform various tasks. Hence you may understand that a computer may not always take the same physical form. Therefore it can be classify into different types.

Computer classification
According to physical size	Super computers	Have higher computing power. They are large in size, expensive and rare. Used for scientific and engineering functions and to solve complex mathematical problems These computers are used in institutes like NASA, large scale businesses and for military purposes.
	Mainframe computers	These have relatively less physical size, computing power and are less expensive than the super computers. In mainframe computers, a number of users connect to one computer using a number of terminals sharing, saving and retrieving data. These are used in large scale businesses and in some large commercial institutions.
	Mini computers	These are lower in physical size, less powerful and less expensive than mainframe computers. Also called common purpose computers. A few users connect to the central computer and through a few terminals share data and information. Used in medium scale institutions such as banks.
	Micro computers	This is a small computer meant for personal use. Consists of a small memory capacity, smaller in size, less speedy and is less expensive. This consumes little electricity. Laptop, hand held, smart phones are some examples for this category.
According to technology	Analog computers	These computers use analog signals such as environmental parameters (speed, pressure, and temperature). We can take as examples speedometers, road lamps with sensors and meteorological machines.
	Digital computers	These computers use digital signals. The machines used by us in day-to-day life are called digital computers.
	Hybrid computers	This is a combination of analog and digital computers. The ECG machine used in hospitals to check the function of the heart is an example for hybrid computers.

Function of a Computer System

As we discussed above the main function of a computer system is to input data, process and store data, and to produce information when needed.

Data and instructions fed to the computer via an input device first go to the Primary Memory. Then those are sent to the CPU for processing. Afterwards the processed data stored in the Primary Memory as information is sent to the output device. The data and information which are to be stored are sent to the Secondary Storage Device. Then the stored information can be sent to an output device through Primary Memory.

Control Unit sends the control signals to all the devices attached to the computer system. Computer memory contains data and instructions. When a computer program works, it sends the relevant data and instructions to CPU.

Basic components of a Computer System

Computer System consists of four major components called;

1. Hardware
2. Software
3. Firmware
4. Live ware

Hardware

Any physical component of a computer system with a definite shape is called a hardware. We can categorize it into;

• Input devices
• Output devices
• Processing devices
• Networking devices
• Memory devices

 Software

Software is a set of commands given to the machine to perform some activity using a computer. It is classified into two types

1. System software
2. Application software

Firmware

The booting instructions stored in the ROM (Read Only Memory) are called firmware.

Liveware

We use this term to denote people using (attached to) computers​.

Evolution of the computer system

Even though at present, there are automated computer systems, the computer too has undergone a similar evolution process as human beings. And today, it has reached the advanced stage.

The computer was born in the attempt to make an adding machine. Abacus was invented around 5000 years ago in order to add numbers.

In due course many new inventions were made. The followings are few of them:

• In 1642, Blaise Pascal invented a machine called Adding Machine. This was the world’s first ever mathematical machine. In other words, it could add and subtract two numbers.
•  In 1674, Gottfried Wilhelm Von Leibnitz improved the machine invented by Pascal. So the device was able to perform multiplication and division too.
•  A French Scientist named Joseph Jacquard invented a mechanical loom using Punch Card System.
•  Charles Babbage started to make his Analytical Engine using the Punch Card System concept. This machine was based on the concepts input, process, output and store. Since this concept helped in the development of the computer, Charles Babbage is called the “Father of the computer”.
•   Madam Ada Augusta Lovelace is considered as the first programmer since she tried to write programs for the Analytical Engine.
•   In the year 1944, a man named Howard Aiken invented the machine called Automatic Sequence Control Calculator at the Harvard University with the assistance of his companions and IBM Company. As a result this machine was named MARK 1.

Computer generations

All the versions of early computers were mechanical in nature. From the time when these machines became automated, we categorize them into various ‘Generations’ as below:

• First Generation (1940-1956)

Vacuum tubes were used as the main technology. For example:  IBM 701.

• Second Generation (1956-1963)

These ones use transistors as the fundamental building block. For example, computers developed in this age are IBM 1620, IBM 7094 etc.

• Third Generation (1964-1975)

These machines used Integrated Circuits (ICs) in place of transistors. A single IC contains many transistors, resistors, and capacitors along with the associated circuitry.

• Fourth Generation (1975-1989)

In this era VLSI (Very Large Scale Integrated) circuits were used. VLSI circuits having more transistors and other circuit elements with their associated circuits on a single chip made it possible to have microcomputers. IBM PC, Apple II are some examples.

• Fifth Generation (1989 to present )

The ULSI (Ultra Large Scale Integration) technology is used in this era resulting in the production of microprocessor chips having millions transistors and other electronic components. Some examples are Desktop, Laptop, Notebook, Ultra book.