GENERATIONS OF COMPUTERS

The growth of the computer industry has been determined by developments in technology. Based on different stages of technological development, computers are classified into different generations.

Overview of Computer Generations

Generation	Period	Main Technology
First Generation	1942–1955	Vacuum Tubes
Second Generation	1955–1964	Transistors
Third Generation	1964–1975	Integrated Circuits (ICs)
Fourth Generation	1975–1980	VLSI Technology and Microprocessors
Fifth Generation	1980–Present	ULSI, AI and Advanced Technologies

FIRST GENERATION OF COMPUTERS (1942–1955)

The first generation of computers was based mainly on vacuum tube technology.

Hardware

The major hardware components used were:

• Vacuum Tubes
• Punch Cards

Features

• Supported machine language only.
• Had slow performance.
• Occupied a very large amount of space because of the use of vacuum tubes.
• Had poor storage capacity.
• Consumed a large amount of electricity.
• Generated a great deal of heat.
• Frequently malfunctioned due to overheating.
• Were non-portable.

Memory

The memory capacity was approximately 4,000 bits.

Data Input

Data was mainly entered through:

• Punched Cards
• Paper Tapes
• Hard-wired programs

Examples

• ENIAC – Electronic Numerical Integrator and Computer
• EDVAC – Electronic Discrete Variable Automatic Computer
• UNIVAC – Universal Automatic Computer
• IBM-701
• IBM-650

VACUUM TUBES

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LARGE SIZE + HIGH HEAT

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HIGH POWER CONSUMPTION

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LOW RELIABILITY

SECOND GENERATION OF COMPUTERS (1955–1964)

Several technological advancements over first-generation computers led to the development of second-generation computers.

Hardware

The major technologies used were:

• Transistors
• Magnetic Tapes

Features

• The first operating systems were developed.
• Batch Processing and Multiprogramming systems were introduced.
• Faster and smaller than first-generation computers.
• More reliable and energy-efficient than the previous generation.
• Used both:
  • Machine Language
  • Assembly Language

Memory

The memory capacity was approximately 32,000 bits.

Data Input

Data was mainly entered through:

• Punched Cards

Examples

• Honeywell 400
• CDC 1604
• CDC 3600
• IBM 7030
• IBM 1401
• IBM 1620

TRANSISTOR

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SMALLER + FASTER

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MORE RELIABLE AND  ENERGY EFFICIENT

THIRD GENERATION OF COMPUTERS (1964–1975)

The third generation of computers was developed with the introduction of Integrated Circuits (ICs).

Hardware

The major technologies used were:

• Integrated Circuits made from semiconductor materials.
• Large-capacity disks.
• Magnetic tapes.

Features

• Supported time-sharing operating systems.
• Faster, smaller, more reliable, and cheaper than previous generations.
• Easier to access and use.
• High-level programming languages were introduced and widely used.

Memory

The memory capacity was approximately 128,000 bits.

Data Input

Data was entered using:

• Keyboards
• Monitors

Examples

• IBM 360/370
• CDC 6600
• PDP-8
• PDP-11

INTEGRATED CIRCUITS

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SMALLER AND FASTER

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MORE RELIABLE

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HIGH-LEVEL LANGUAGES

FOURTH GENERATION OF COMPUTERS (1975–1980)

The fourth generation of computers was based on Very Large-Scale Integration (VLSI) technology and the development of microprocessors.

Hardware

The major technologies used were:

• Integrated Circuits using VLSI technology.
• Semiconductor memory.
• Magnetic tapes.
• Floppy disks.
• Microprocessors.

Features

• Supported multiprocessing and distributed operating systems.
• Supported object-oriented and high-level programming.
• Became smaller and easier to use.
• Hand-held computers began to evolve.
• Required little or no external cooling.
• Became more affordable.
• Networks and the Internet began to develop.
• Graphical User Interfaces (GUIs) and the mouse became important developments.

Memory

The memory capacity was approximately 100 million bits.

Data Input

Data was entered using:

• Improved hand-held devices.
• Keyboard.
• Mouse.

Examples

• Apple II
• VAX 9000
• CRAY-1 (Supercomputer)
• CRAY-X-MP (Supercomputer)

VLSI

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MICROPROCESSOR

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PERSONAL COMPUTER

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NETWORKS + GUI + MOUSE

FIFTH GENERATION OF COMPUTERS (1980–PRESENT)

The fifth generation represents modern and advanced computer technology. Significant developments in computer components and operations have made these computers more powerful, compact, reliable, and user-friendly.

Hardware and Technologies

The major technologies include:

• Integrated Circuits using ULSI technology.
• Nano technology.
• Large-capacity hard disks with RAID support.
• Powerful servers.
• Internet technology.
• Cluster computing.
• Parallel processing.

Features

• Powerful, affordable, reliable, and easy to use.
• Portable and faster due to the use of parallel processors and advanced integrated circuits.
• Introduction of Artificial Intelligence (AI).
• Development of Expert Systems.
• Rapid software development is possible.
• Capable of recognising images and graphics.
• Increasing use of voice recognition and other intelligent technologies.

Memory

Modern computers have extremely large storage and memory capacities. The capacity continues to increase with technological advancement.

Data Input

Data can be entered through:

• CD-ROM
• Optical Disks
• Touch-sensitive devices
• Voice-sensitive devices
• Keyboards and other modern input devices

Examples

• IBM Computers
• Pentium-based Computers
• PARAM Supercomputers

FIFTH GENERATION

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┌─────────────┼─────────────┐

│             │             │

AI        ROBOTICS       EXPERT

SYSTEMS

│             │             │

└─────────────┼─────────────┘

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INTELLIGENT COMPUTING

Memory Trick

V – T – I – V – U

• V – Vacuum Tubes
• T – Transistors
• I – Integrated Circuits
• V – VLSI
• U – ULSI

Remember:
“Very Tall Indians Visit Universities”
→ V – T – I – V – U

1. Which technology was used in the First Generation of computers?
(A) Transistors
(B) Vacuum tubes
(C) Integrated Circuits
(D) Microprocessors
Answer: (B) Vacuum tubes

2. ENIAC belongs to which generation of computers?
(A) First Generation
(B) Second Generation
(C) Third Generation
(D) Fourth Generation
Answer: (A) First Generation

3. UNIVAC is an example of which generation of computers?
(A) First Generation
(B) Second Generation
(C) Third Generation
(D) Fifth Generation
Answer: (A) First Generation

4. Which electronic component was used in Second Generation computers?
(A) Vacuum tubes
(B) Transistors
(C) Integrated Circuits
(D) Microprocessors
Answer: (B) Transistors

5. Which generation of computers used Integrated Circuits (ICs)?
(A) First Generation
(B) Second Generation
(C) Third Generation
(D) Fourth Generation
Answer: (C) Third Generation

6. Which generation of computers introduced the use of microprocessors?
(A) First Generation
(B) Second Generation
(C) Third Generation
(D) Fourth Generation
Answer: (D) Fourth Generation

7. The Fifth Generation of computers is mainly associated with:
(A) Vacuum tubes
(B) Transistors
(C) Artificial Intelligence
(D) Magnetic drums
Answer: (C) Artificial Intelligence

8. Which of the following is an example of a Second-Generation computer?
(A) ENIAC
(B) UNIVAC
(C) IBM 1401
(D) Apple II
Answer: (C) IBM 1401

9. Which of the following is an example of a Fourth-Generation computer?
(A) ENIAC
(B) IBM 1401
(C) Apple II
(D) UNIVAC
Answer: (C) Apple II

10. The first generation of computers mainly used:
(A) Machine language
(B) Assembly language
(C) High-level language
(D) Natural language processing
Answer: (A) Machine language

11. UNIVAC is an example of
 (A) first generation computer
 (B) second generation computer
 (C) third generation computer
 (D) fourth generation computer

Communication Officer 2024

12. Which generation of computers uses mnemonic codes?
 (A) First
 (B): Second
 (C) Third
 (D) Fourth

Liaison Officer (LO) 2025

Answer: (B) Second