Generation of Computers from 1st to 5th and their Features

Generation of computers is a classification of computers into different groups according to their manufacturing date and the memory device and other hardware and software technology used in them. So, the generation of computers is described as a stage of technological development or innovation. It provides a framework for the growth and development of more powerful and more useful computer systems.

When computer generation goes higher that is from 1st to 2nd, 2nd to 3rd, and so on, then we find that the processing or operating speed, processing capability, and storage capacity are increasing but size, processing capability, and storage capacity are increasing but size, energy consumption, heat generation, cost, and complexity are decreasing gradually.

There are Five Generations of Computers:

First Generation Computer (1940 - 1956)

First-generation computers were operated by thousands of vacuum tubes or thermionic valves and magnetic storage devices were used to store data and instruction. Most data and instructions were entered onto the PCs by means of punch cards or paper tape. Output was in the same form human operations had to set switches before a program could run.

First Generation computer (UNIVAC)
UNIVAC Computer

Features of First Generation Computers:
  1. These PCs were dependent on vacuum tube innovation.
  2. The vacuum tubes required great amounts of energy and generation mush heat, therefore air-conditioning was essential.
  3. The computers of first-generation were very large in size and required a lot of space.
  4. These were non-portable and very slow processing or operating time was in a millisecond.
  5. Binary or Machine language, in the form of 0s and 1s was used for programming and hence was very difficult to program and use.
  6. These machines were unreliable and lack of versatility and speed.
  7. Punched cards were used as an input device.
  8. The operating case, as well as the cost of computers, was very high.
  9. Each machine component had to be assembled manually. Hence, the commercial appeal of these computers was poor.

Examples of first-generation computers were IBM (International Business Machine) 700 series, ENIAC (Electronic Numerical Integrator and Calculator),EDVAC (Electronic Discrete Variable Automatic Computer). UNIVAC (UNIVersal Automatic Computer) etc.

Vacuum Tubes

A vacuum tube is an empty glass chamber containing a positive terminal and a negative between which is conducted in a full or incomplete vacuum. A network between these terminals controls the stream of power or electricity.

The Vacuum tubes ( thermionic valves) were predominantly used in electronic devices such as televisions, radios, and computers. It is still in use in some electronic devices.
The main drawback of tubes is that they require bulky power supplies and high voltages which can cause an electric shock hazard.

Vacuum Tubes
Vacuum Tube

Second Generation Computer (1956 - 1963)

The invention of the transistor greatly changes the computer's development. The transistor replaced the large, cumbersome vacuum tube-based first-generation computers. As a result, the size of the machine has been lessening ever since. Magnetic cores were used as primary memory and magnetic disks, tapes were used as a secondary storage device.

Assembly language, in the form of alphanumeric that is mnemonics, was used for the program. As a result, programming became less cumbersome. An early high-level programming language such as FORTRAN (Formula Translator), AlGOL (Algorithmic Language), and COBOL (Common Business-Oriented Language) also came into existence in this period.

Features of Second Generation Computers:
  1. These computers were based on transistors' technology.
  2. They were smaller, faster, more reliable, accurate, and more energy-efficient as compared to the first-generation computers.
  3. They were portable and generated less amount of heat as compared to the first-generation computers.
  4. These computers still required air conditioning.
  5. Processing or operating speed was increased to microseconds from milliseconds.
  6. In the form of alphanumeric that is mnemonics, assembly language was used to program, and hence programming became more time efficient and less cumbersome.
  7. Manually assembly or individual components into a functioning unit was still required.

Examples of the second generation of computers are IBM 1401, IBM 7090, PDP 8, etc.


The transistor is derived from the two words "transfer" and "register". It is a device made of three-terminal semiconductor materials that amplify the electric signal or open or close the electronic circuit.
They were a lot smaller than vacuum tubes and drain significantly less power. Electronic circuits could be made more complicated, with a larger number of transistors switching quicker than tubes. Transistors were invented by three scientists. They are John Bardeen, William Shockley, and Walter Brattain in 1947 and won the novel prize in 1956 for it.

Transistor (Second generation computer)

Third Generation Computer (1964 - Early 1970s)

Despite the fact that transistors were more developed than vacuum tubes they still generated more heat which damaged the computer's internal parts. Scientists later figured out how to fit much more parts on a single chip, considered a semiconductor that is an integrated circuit. Therefore, PCs turned out to be ever smaller as more components were compressed onto the chip. Another third-generation development involves the utilization of an operating system that permitted machines to run various projects at once with a central program that observed and coordinated the computer's memory.

Features of Third Generation Computers:
  1. The integrated circuit is the principal component of these computers.
  2. They were smaller in size, more reliable, accurate than the previous generation of computers.
  3. Power consumption and heat generation were less than the previous generation of computers.
  4. Computers became portable for the first time because of personal or desktop computers.
  5. Semiconductor memory was used as primary memory.
  6. The keyboard and monitor were used as input and output devices respectively for the first time.
  7. The magnetic disk was used as secondary memory.
  8. The operating system for automatic processing and multiprogramming introduced.
  9. Processing or operating speed was increased to nanoseconds from microseconds.
  10. Manual assembling of individual components was not required. Hence, commercial production became easier and cheaper.

Examples of third-generation computers are NCR 395, B6500, etc.

Integrated Circuits (ICs)

An integrated circuit is a tiny electronic circuit made up of millions of transistors, resistors, and capacitors which are combined into the single-chip of semiconducting material. ICs range in complexity from simple logic modules and amplifiers to finalize microcomputers containing a great many components.

Integrated circuits have become the significant components of almost all electronic gadgets. These circuits are more developed, consume less power, have high processing speeds compared to the vacuum tubes and transistors.

Integrated Circuit (IC) (Third generation computer)
Integrated Circuit (IC)

Fourth Generation Computer ( Early 1970s - Till Date)

Fourth Generation PCs are the advanced these days most recent PCs. The size of the processor decreased with the development of integrated circuits. Very Large Scale Integration (VLSI) and Ultra Large Scale Integration (ULSI) ensured that millions of components could be fit into a small chip. It minimized the size and cost of the computers simultaneously increasing power, productivity, and reliability.

Computers of Fourth-generation use VLSI (Very-large-scale integration ) chips for processing, storing data, and controlling chips, they use microprocessors as CPU.

Fourth Generation Computer (Desktop Computer)
Desktop Computer

Features of Fourth Generation Computers:
  1. These computers were based on microprocessors.
  2. The computers are powerful, compact, affordable, portable, and totally reliable.
  3. These computers are the cheapest and smallest among all the other generation computers.
  4. Use of magnetic disk and optical disk with huge capacity for the secondary storage device.
  5. Processing speed increased very fast up to picoseconds.
  6. Multi-programming, multi-processing, multimedia, and distributed computing are possible.
  7. Because of the microprocessor, microcomputers such as Pcs, laptops, and Notebook computers were invented.
  8. Fourth-generation language and application software for microcomputers became popular.
  9. Graphical user interface and further refinement in input and output devices introduced.
  10. Interconnection of computers leads to better communication and resource sharing.

Examples of fourth-generation computers are Apple II, Altair 8800, CRAY-1,etc.


A microprocessor is an electronic circuit that performs the tasks of a computer's CPU. It is sometimes called a logic chip. It is the "engine" that goes into the motion when you turn your computer on. A microchip is intended to perform arithmetic and logic tasks that utilize small number-holding areas called registers. When the computer is turned on, the microprocessor gets instruction from a basic input/output system (BIOS) stored in computer memory. After that, the operating system software loads into computer memory to operate the CPU and perform different tasks.

The first commercial microprocessor was the intel 4004 which was made by Intel corporation in 1971. It was a 4-bit processor because it could process only bits at a time. It is considered one of the most important generations because many hardware and software technology achievements took place during this generation.

Microprocessor (CPU) Fourth generation computer)

Fifth Generation Computer (Present and Beyond)

The computers of his generation are still in the development stage, but scientists are trying since 1990. The computers of this generation will use Artificial Intelligence (AI) and bio-chips as memory devices so that they can think and decide like human beings. Bio-chips are made up of Biological organisms and protein fibers obtain from the living organism. So these computers will have the power of sense, logic, decision-making capability, and decision-making capability parallel processing. Developments in computer hardware and software design may produce computers far more power than those in current use.

Features of Fifth Generation Computers:
  1. These computers will be a fully parallel processing capacity.
  2. Computers will be intelligent and knowledge base because of AI.
  3. Computers will use superconductor memory like bio-chips and Gallium Arsenide as memory devices so that, the speed will be very high.
  4. Instead of HLL (high-level language), natural languages like English, Japanese, etc. will be used for operating computers, giving instructions, and programming to make computer programs and software.
  5. The application of AI in fifth-generation computers has also enabled an expert system.
  6. The input and output for these machines will be in the form of graphic images or speeches.
  7. They are used in the field of medicine, treatment planning, monitoring, and so on, on a very small scale.
  8. The language of the operating system will be PROLOG, LISP, etc.

Artificial Intelligence (AI)

Artificial Intelligence (AI) is the region of software engineering concentrating on making machines that can take part in practices that people consider intelligent. 50 years of development and research in AI programming have made humans capable to turn the fantasy of intelligent machines and gadgets into reality.

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