Generations of Computer - The Evolution of Computers

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Generations of Computer - The Evolution of Computers

Sameeksha Medewar
Last updated on July 13, 2024

    Computers have come a long way. Today, they have become an inseparable companion of human beings, helping them perform diverse activities quickly and efficiently. Modern computers are pretty smart and compact in size. They are portable, consuming very less space.

    However, this was not the case with traditional computers. Earlier, they were used to perform calculations simply. In addition, they were huge in size that would fill an entire room. Technological advancements have made today’s systems more powerful and intelligent.

    Charles Babbage invented the first mechanical computer in the 19th century. Before the advent of mechanical computers, people used mechanical calculators. Some popular mechanical calculators include Abacus, Pascal’s Calculator, Stepped Reckoner, Pascal’s Calculator, Comptometer and Comptograph, The Difference Engine, Analytical Engine, and The Millionaire.

    If you are interested in gaining insights into the evolution of computer systems, continue reading this article.

    This article will discuss the different generations of computer systems and how they have evolved over the years.

    Basic Computer Terminology

    Before we discuss the generations of computer systems, let us first go through some basic terms related to computers.

    • Integrated Circuit (IC)

    Simply referred to as IC, an integrated circuit is a semiconductor chip consisting of thousands of resistors, transistors, diodes, and capacitors. It functions as an amplifier, timer, oscillator, logic gate, memory, and microcontroller or microprocessor.

    • Microprocessors

    A microprocessor is part of a computer architecture that accepts user input, performs arithmetic and logical operations, and displays the desired output. In other words, it is a programmable device on a chip that retrieves instructions from memory and executes them to provide results.

    • Central Processing Unit (CPU)

    CPU, or Central Processing Unit , is the brain of a computer. It is an ecosystem of complex circuitry responsible for running the operating system and all other installed applications. It functions similarly to a microprocessor and executes all the provided instructions.

    The major difference between a microprocessor and a CPU is that the former is a single integrated circuit (IC) containing arithmetic, logic, and control units. In contrast, a CPU is a complex hardware unit consisting of multiple components, such as cache memory, bus, interface unit, etc.

    • Magnetic Drum

    A magnetic drum is a storage device designed by Gustav Tauschek in 1932 in Austria. It was used as the main working memory in many traditional computers like modern computers use RAM as their main memory. It is a metal cylinder covered with magnetic iron-oxide material. The data is stored on its surface with the help of changing magnetic polarities.

    • Magnetic Core

    A magnetic core is an array of small rings of magnetized material. It is used to store information.

    • Memory

    As human brains have a memory to store information, computers have a memory to store data, programs, and instructions.

    • Vacuum Tube

    A vacuum tube is an electronic device that controls the flow of electrons in a vacuum. It serves as an amplifier, switch, or display screen.

    • Transistor

    A transistor is a tiny semiconductor that controls the flow of power and voltage, generates and amplifies electrical signals, and serves as a gate or switch for them. It is covered with three semiconductor layers, and each layer is capable of carrying the current.

    • Artificial Intelligence

    Artificial intelligence is a technological breakthrough of the 20th century, evolving at a greater pace even today. As the name suggests, artificial intelligence implies the simulation of human intelligence by computer systems and other electronic devices. It refers to the ability of electronic devices to learn, reason, and comprehend meaning.

    What are the Generations of Computer?

    The generations of computer systems imply technological advancements in the development of computer technology. Each generation of a computer marks a substantial advancement in hardware, architecture, and capabilities.

    Simply put, the term ‘generation’ refers to the development and breakthroughs in computer systems in terms of hardware and software.

    There are 5 generations of computer systems –

    Generations of Computer - Explore How Computers Evolved Over Time

    Let us now dive deeper into the evolution of computer systems.



    Evolving Hardware




    Vacuum tubes, magnetic drums, punch cards




    Transistors, magnetic cores, high-level languages

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



    Integrated circuits, operating systems

    IBM 360, IBM 370, PDP-11, NCR 395, B6500, UNIVAC 1108



    Microprocessors, personal computers

    IBM PC, STAR 1000, APPLE II, Apple Macintosh, Alter 8800



    AI, parallel computing, advanced interfaces

    Desktops, laptops, tablets, smartphones

    1. First Generation

    The first-generation computers used vacuum tubes as their core technology. They were extremely large in size and heavy.

    • They used a low-level programming language called machine language.
    • There was an absence of an operating system .
    • Primary uses were storage, calculation, and control.
    • These computers consumed a lot of electricity and space (nearly an entire room).
    • They generated a significant amount of heat. Hence, they required a large cooling system.
    • The storage capacity was very low.


    • Memory: Magnetic tapes and magnetic drums
    • Input/Output Devices: Paper tapes and punch cards
    • Speed: Extremely slow


    • ENIAC: Its full form is Electronic Numerical Integrator and Computer. J. Presper Eckert and John V. Mauchly developed ENIAC, a general-purpose computer with 18,000 vacuum tubes.
    • EDVAC: Von Neumann designed EDVAC (Electronic Discrete Variable Automatic Computer). It was one of the first stored-program computers, which stored data as instructions.
    • UNIVAC: Universal Automatic Computer (UNIVAC) is another computer developed by Eckert and Mauchly in 1952.

    2. Second Generation

    The second-generation computers replaced vacuum tubes with tiny components called transistors. They were much smaller than vacuum tubes. Hence, they made second-generation computers more compact and smaller in size than first-generation computers.

    • Second-generation computers leveraged assembly languages rather than machine language.
    • They also employed a few high-level languages, such as FORTRAN, ALGOL, and COBOL.
    • The use of transistors dissipated less heat and consumed less power.
    • The magnetic core technology helps these computers store instructions in memory.
    • Calculations were just a matter of microseconds.
    • These computers included an operating system.
    • They required time-to-time maintenance.
    • A cooling system was a must.


    • Memory: Magnetic core and magnetic tape/disk
    • Input/Output Devices: Paper tapes and punch cards
    • Speed: Faster than first-generation computers


    Some major examples of second-generation computers involve UNIVAC-1108, IBM-7070, IBM-1400 series, IBM-1600 series, IBM-7000 series, CDC-1604, and Honeywell-400.

    3. Third Generation

    Third-generation computers took a drastic shift from transistors to integrated circuits (ICs). An IC is a semiconductor chip with multiple transistors placed on it. The foremost features of this generation of computers were speed and reliability.

    • ICs typically include transistors, resistors, and capacitors on a single silicon chip.
    • Third-generation computers used high-level languages like COBOL, FORTRAN - II to IV, BASIC, ALGOL-68, and PASCAL PL/1.
    • There was an increase in memory or storage capacity.
    • ICs significantly reduced the size of computers.
    • These computers included more sophisticated operating systems.
    • They had high processing speed and improved overall performance.
    • They supported complex calculations and faster program execution.
    • Third-generation computers generated significantly less amount of heat and consumed less power.
    • They required a cooling system.


    • Memory: Large magnetic core and magnetic tape/disk
    • Input/Output Devices: Magnetic tape, monitor, keyboard, printer, etc.
    • Speed: Faster and more reliable than the computers of the previous generation


    Popular examples of third-generation computers include IBM 360, IBM 370, PDP-11, NCR 395, B6500, and UNIVAC 1108.

    4. Fourth Generation

    Microprocessors were the core technology of the fourth-generation computers. The primary advantage of this technology was that a microprocessor served as a single chip to perform arithmetic, logic, and control functions.

    A microprocessor, at that time, was based on Large Scale Integration and Very Large Scale Integration (VLSI). It was a combination of several integrated circuits (ICs).

    • Fourth-generation computers were very compact in size because of microprocessors.
    • They leveraged high-level programming languages , such as C, C++, etc.
    • Time-sharing, network-based, distributed, multiprocessing, and multiprogramming operating systems were used.
    • These computers have introduced the concept of personal computers (PCs) and computer networks.
    • They were highly energy-efficient, faster, and reliable.
    • The amount of heat generated was also reduced greatly, which was almost negligible.
    • There was no use of a cooling system. Instead, computers had a built-in cooling fan.


    • Memory: Semiconductor memory, such as RAM, ROM, etc.
    • Input/Output Devices: Keyboard, printer, optical scanner, mouse, pointing devices, etc.
    • Speed: Extremely faster than previous generations


    IBM-5100, STAR-1000, APPLE II, IBM-4341, PDP-11, DEC-10, CRAY-1, CRAY-X.MP, Apple Macintosh, and Alter-8800 are some examples of fourth-generation computers.

    5. Fifth Generation

    The latest and current generation of computers uses artificial intelligence as their core technology. In addition, they leverage ULSI (Ultra Large Scale Integration) technology, which transformed the development of microprocessors. With the help of ULSI, a microprocessor can combine millions of electronic devices.

    • Fifth-generation computers are known for their speed, reliability, and performance.
    • Their size is smaller than previous generation computers, while the areas of use have increased significantly.
    • They support high-level languages, such as C, C++, Java, .Net, etc.
    • They also understand and interpret human language.
    • These computers are highly smart and can handle multitasking efficiently.


    • Input/Output Devices: Trackpad, touchscreen, microphone, keyboard, monitor, scanner, printer, mouse, etc.
    • Speed: Extremely fast


    Desktops, laptops, Notebooks, Chromebook, tablets, etc., are examples of fifth-generation computers.


    Here ends our discussion on generations of computer systems. They have evolved from large, room-sized dimensions to hand-held devices like tablets and notebooks. Besides the size, computers have drastically transformed in terms of hardware and software. From vacuum tubes to artificial technology as the core technology, computers have made great strides.

    We hope this article has helped you gain a better understanding of the evolution of computer systems.

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