Generations of Computers

Generations of computers notify us about the evolution of computer technology over years. The terminology ‘Generations of Computer’ not only defines the evolution of hardware technology but also the evolution of software technology along with it. As hardware and software together make up the entire computer system.
Before getting into the generations of computers let us first start with the definition of the computer.

What is Computer?

We can define a computer as an electronic device that we use to process data and generate useful information. Apart from processing data computers are also useful in storing data. Somehow when all the computers around the world are connected to each other by some means then the formed network is referred to as the internet.

We use computers for sending mail, creating and storing documents and files, calculations, playing games, browsing the internet, running software, etc. Now let us move towards the generations of computers. We can classify generations of computers into five generations.

Generations of Computers

  1. First Generation
  2. Second Generation
  3. Third Generation
  4. Fourth Generation
  5. Fifth Generation

Before the evolution of modern computers, few mechanical calculators were used for computations. These mechanical calculators were invented to ease complex mathematical calculations. Let us discuss these:

Abacus (ca 2700 BC)

Abacus is usually meant for arithmetic calculations. It is made up of a wooden frame that is consist of several beads. Abacus does not have any mechanical function units. Abacus is still famous and it’s a very handy tool for performing calculations.


Pascals Calculator (1652)

The pascals calculator was used to add, subtract, multiply and divide using repetition.

Stepped Reckoner (1694)

This machine can calculate all four arithmetic calculations. The machine has a cursor to select the operands and also has memory to store the result.

Arithomometer (1820)

It was the first successful mechanical calculator. It was able to perform long and complex arithmetic operations.

Comptometer (1887) and Comptograph (1889)

It was the first mechanical calculator that came along with the keypad. This keyboard has 8 column that has 9 keys in each column. along with the number key, it has some special keys for currency and weight.

The Difference Engine (1822)

This calculator was able to hold seven operands at once, where each operand can be 31 digits. This machine was also capable of taking the results of the previous calculation as input

Analytical Engine (1834)

This calculator has two input streams and three output streams. It has a processing unit and memory that holds a set of programming instructions.

The Millionaire (1893)

It was the first mechanical calculator that was capable of directly multiplying numbers, unlike the earlier calculators that use to perform multiplication by repeated addition.

First Generation Computer (1940s -1950s)

The First generation computers evolved between 1940 – 1956. The main functional component of the first-generation computer was vacuum tubes. The vacuum tube is a glass tube that contains electrodes. These electrodes control the flow of electrons. The vacuum tube was used as switches, amplifiers, and display screens (cathode ray tube (CRT)).

These vacuum tubes were made of glass they were fragile, big in size and they also consume a lot of power. To produce a computer up to 100 vacuum tubes were used. Due to these reasons the produced computers were heavy and large in size. The first-generation computer was so huge that they use to take up an entire room.

First Generation Computer Vaccum Tubes

The input and output of the first-generation computer were paper tapes and punch cards. These computers were used for calculations, controlling, and storage. For storage, they used magnetic tapes and magnetic drums.

Example of First-Generation Computers

  • IBM 701
  • IBM 650

Second Generation Computer (1950s -1960s)

The second-generation computer evolved from 1950 to 1960. The main functional unit of the second-generation computer was transistors. Transistors were much smaller, lightweight and comparatively consume less power, and even generate less heat.

The transistors are the semiconductor devices used to regulate current, amplify, generate the electric signal, and switch. FORTRAN, ALGOL, and COBOL were used to program the second-generation computers. The second-generation computer was faster as compared to the first-generation computers.

Second Generation Computer Transistors

Input and output to second-generation computers were paper tapes and punch cards. The storage units were made of magnetic tapes and magnetic drums.

Examples of Second Generation Computer

  • PDP-8
  • IBM1400 series
  • IBM 7090 and 7094
  • UNIVAC 1107
  • CDC 3600

Third-Generation Computers (1960s- 1970s)

The third-generation computer evolved between the 1960s to 1970s. The main functional unit of the third-generation computer was integrated circuits (IC). The integrated circuit was silicon chips on which a variety of miniature transistors were placed.

Third Generation Computer Integrated Circuits

A single IC would have many transistors, registers, and capacitors implanted in it. This reduces the size of third-generation computers. The input and output units of these computers were the keyboard, monitor, printer, etc.
Here also the memory units were magnetic tape and magnetic tape. BASIC, COBOL, and Pascal were the programming language used to program the third-generation computer. They were faster than the first and second-generation computers, comparatively smaller in size, and consumed less power.

Examples of Third Generation Computers

  • IBM 370
  • IBM 360
  • UNIVAC 1108

Fourth Generation Computer (1970s – Uptill now)

The fourth-generation computer started evolving during the 1970s and is continuously evolving even now. The main functional unit of a fourth-generation computer is the microprocessor. Microprocessors are very large-scale integration (VLSI) circuits.

Approximately thousands of transistors are embedded in a single microprocessor. That’s why we refer to it as a large-scale integrated circuit. The input and output devices of fourth-generation computers are a keyboard, mouse, monitor, printer, etc. These computers were small in size, faster, and also consumed less power. They were much more user-friendly and thus become a customary devices.

Fourth Generation Computer Microprocessor

The memory units of fourth-generation computers are made of semiconductors, these units are RAM and ROM. Although the hard disk still used a magnetic disk. High-level languages such as C, C++, C#, and Java are used to program fourth-generation computers. The computer network or internet came into existence with the fourth generation of computers.

Examples of Fourth Generation Computers

  • STAR 1000
  • IBM PC

Fifth Generation Computer (Present and Future)

The fifth-generation computers are trying to produce computers with human-like decision-making capabilities. The technology it uses is artificial intelligence (AI). It uses techniques like fuzzy logic, neural network, and genetic algorithm.

Although AI has not been completely successful it’s going to be a reality soon. The fifth generation computers are trying to implement soft computing. The input and output units of fifth-generation computers are sensors, scanners, keyboards, printers, monitors, mouse, etc.

Examples of Fifth Generation Computer

  • Desktops
  • Laptops
  • Tablets
  • Smartphones

Thus these are the five generations of computers. We have studied almost all the features of computers of every generation.

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