Generations of Computers – JSS1 Computer Studies Lesson Note (First Term)

Computer generations are the stages in the development of computers, each marked by the main technology it used. There are five: the first generation used vacuum tubes, the second used transistors, the third used integrated circuits, the fourth used microchips, and the fifth is based on artificial intelligence.

Behavioural objectives

By the end of the lesson, students should be able to:

• name the five generations of computers;
• state the main technology used in each generation;
• list the main features of each generation;
• give examples of computers from each generation;
• explain what artificial intelligence is.

What are the five generations of computers?

1. First generation computer
2. Second generation computer
3. Third generation computer
4. Fourth generation computer
5. Fifth generation computer

What was the first generation of computers (1945 to 1955)?

The first generation of computers began with the Electronic Numerical Integrator and Computer (ENIAC). It was developed by John Presper Eckert and John W. Mauchly. These machines had vacuum tubes, resistors, punched cards or punched tape input and output devices, and RAM.

Examples of first-generation computers include ENIAC, EDSAC, UNIVAC 1, IBM 650 and IBM 608 (EDVAC: Electronic Discrete Variable Automatic Computer; UNIVAC: Universal Automatic Computer).

Features of the first generation

• Vacuum tube technology
• Unreliable
• Supported machine language only
• Very costly
• Generated a lot of heat
• Slow input and output devices
• Huge size
• Needed air conditioning (A.C.)
• Non-portable
• Consumed a lot of electricity

Some computers of the first generation

• ENIAC
• EDVAC
• UNIVAC
• IBM-701
• IBM-650

What was the second generation of computers (1956 to 1963)?

The second generation of computers used transistors, which replaced the vacuum tubes of the first generation. Assembly language replaced machine language. Computer memory became larger, and programs were stored inside the computer’s memory. High-level languages such as COBOL (Common Business-Oriented Language), ALGOL (Algorithmic Language) and FORTRAN (Formula Translator) were used.

Features of the second generation

1. They used transistor technology
2. Faster than first-generation computers
3. They generated a lesser amount of heat
4. They were smaller than first-generation computers
5. Instructions were written in high-level language
6. Instructions were coded in assembly language
7. They were less expensive to buy and power
8. They were faster and more reliable
9. They had limited internal memory
10. They used external storage

Some computers of the second generation

• IBM 1620
• IBM 7094
• CDC 1604
• CDC 3600
• UNIVAC 1108

What was the third generation of computers (1964 to 1971)?

The third generation of computers came with the integrated circuit (IC), invented in 1958 by Jack Kilby. Operating systems allowed machines to run different programs. This period also saw the introduction of small and inexpensive computers that individuals could afford.

Examples of third-generation computers are ICL 1900, IBM 360/370, Honeywell 200 series, CDC 6000 and UNIVAC 1100.

Features of the third generation

1. They used integrated circuit technology
2. More reliable
3. Smaller size
4. Generated less heat
5. Faster
6. Lesser maintenance
7. Still costly
8. A.C. needed
9. Consumed less electricity
10. Supported high-level language

Some computers of the third generation

• IBM-360 series
• Honeywell-6000 series
• PDP (Programmed Data Processor)
• IBM-370/168
• TDC-316

What was the fourth generation of computers (1980s to 1990)?

Fourth-generation computers are the modern-day computers. They saw the development of the very small chip, large-scale integrated circuits, ultra-large-scale integrated circuits (ULSI) and enhanced types of integrated circuits, also called microchips. They also have a microprocessor equipped with Read-Only Memory (ROM).

Examples of fourth-generation computers are Intel’s 8080, IBM 5100 PC, Commodore’s Amiga A10001, Pentium I, Pentium II, Pentium III, Pentium IV, Pentium M, Giga Pro and Celeron.

Features of the fourth generation

• VLSI technology used
• Very cheap
• Portable and reliable
• Use of PCs
• Very small size
• Pipeline processing
• No A.C. needed
• Concept of the Internet was introduced
• Great developments in the field of networks
• Computers became easily available

Some computers of the fourth generation

• DEC 10
• STAR 1000
• PDP 11
• CRAY-1 (supercomputer)
• CRAY-X-MP (supercomputer)

What is the fifth generation of computers (21st century and beyond)?

These are the computers of the future. They have high speed of operation, perform multiple tasks and have artificial intelligence. Artificial intelligence is a term for giving human behaviour and characteristics to man-made machines. The method by which computers imitate human intelligence is called the knowledge information processing system (KIPS).

Examples of fifth-generation computers are Wallet PC, virtual reality, Linux watch, wearable PC, Ballistic translator, PUMA, Cog, DANTE, WAMBOT-2 and HELPMATE.

Some computer types of the fifth generation

• Desktop
• Laptop
• Notebook
• Ultrabook
• Chromebook

Features of the fifth generation

1. They will come in various forms and shapes
2. They will have a high speed of operation
3. They can make decisions
4. They will have artificial intelligence
5. They will have a relatively small size

Evaluation

1. Name the five generations of computers.
2. Which technology replaced vacuum tubes in the second generation?
3. Who invented the integrated circuit, and in what year?
4. State four features of third-generation computers.
5. What is artificial intelligence?

Assignment

1. Draw a table showing the five generations of computers, the period of each generation and the main technology it used.
2. List three examples of computers from each of the first four generations.