Generations of Computers

The generation of computers refers to the classification of computers based on the core hardware technology, programming languages, and capabilities used during a particular period.

Computers are broadly divided into five generations.

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1️. First Generation Computers (1940–1956)

Technology: Vacuum Tubes

Description

First-generation computers used vacuum tubes as their main electronic component. These tubes acted as switches and amplifiers but consumed huge power and generated excessive heat.

Characteristics

• Very large in size (room-sized)
• High power consumption
• Generated excessive heat
• Frequent hardware failures
• Very slow processing speed
• Required air conditioning
• Not portable
• Very expensive

Programming Languages

• Machine Language
• Assembly Language

Input / Output Devices

• Input: Punch cards, paper tape
• Output: Printed sheets

Examples

• ENIAC
• EDVAC
• EDSAC
• UNIVAC-I
• IBM 701

Limitations

• High electricity consumption
• Poor reliability
• Difficult to program
• Limited memory and storage

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2️. Second Generation Computers (1956–1963)

Technology: Transistors

Description

Second-generation computers replaced vacuum tubes with transistors, making systems smaller, faster, and more reliable.

Characteristics

• Smaller size than the first generation
• Less heat generation
• Lower power consumption
• More reliable
• Faster processing
• Less maintenance required

Programming Languages

• High-Level Languages introduced
• FORTRAN
• COBOL
• Assembly Language

Input / Output Devices

• Input: Punch cards, magnetic tape
• Output: Printouts

Examples

• IBM 7094
• CDC 1604
• UNIVAC 1108
• Honeywell 400

Improvements over First Generation

• Reduced size and cost
• Improved speed and reliability
• Easier programming

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3️. Third Generation Computers (1964–1971)

Technology: Integrated Circuits (ICs)

Description

Third-generation computers used Integrated Circuits, which combined multiple transistors into a single chip.

Characteristics

• Much smaller size
• Lower power consumption
• High speed and accuracy
• Better reliability
• Introduction of operating systems
• Multiprogramming and time-sharing

Programming Languages

• BASIC
• COBOL
• FORTRAN
• Pascal

Input / Output Devices

• Keyboard
• Monitor
• Magnetic disks

Examples

• IBM System/360
• PDP-8
• PDP-11
• Honeywell 6000 series

Key Innovations

• Real-time processing
• Operating systems
• Multi-user support

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4️. Fourth Generation Computers (1971–Present)

Technology: Microprocessors (VLSI)

Description

Fourth-generation computers are based on microprocessors, where the entire CPU is placed on a single chip using VLSI (Very Large Scale Integration) technology.

Characteristics

• Very small and portable
• Very high processing speed
• Low cost
• High storage capacity
• Reliable and efficient
• User-friendly interfaces

Programming Languages

• C
• C++
• Java
• Python

Input / Output Devices

• Keyboard, mouse
• Monitor
• Touch screens

Examples

• IBM PC
• Apple Macintosh
• Desktop computers
• Laptops

Major Developments

• Personal computers (PCs)
• Graphical User Interfaces (GUI)
• Networking and the Internet

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5️. Fifth Generation Computers (Present & Future)

Technology: Artificial Intelligence (AI)

Description

Fifth-generation computers are designed to use Artificial Intelligence, enabling machines to think, learn, and make decisions like humans.

Characteristics

• Based on AI and machine learning
• Natural Language Processing
• High-speed parallel processing
• Self-learning capability
• Quantum computing concepts

Programming Languages

• Python
• Prolog
• LISP
• R

Applications

• Robotics
• Expert systems
• Speech recognition
• Autonomous vehicles
• Virtual assistants (Alexa, Siri)

Examples

• AI-based systems
• Supercomputers
• Quantum computers (experimental)

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Comparison Table

Generation	Technology	Size	Speed	Languages	Examples
1st	Vacuum Tubes	Very Large	Very Slow	Machine	ENIAC
2nd	Transistors	Smaller	Faster	FORTRAN	IBM 7094
3rd	ICs	Compact	High	BASIC	IBM 360
4th	Microprocessor	Very Small	Very High	C, Java	PC
5th	AI	Advanced	Ultra High	Python	AI Systems

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