History of Computer – SS1 Data Processing Lesson Note (First Term)

Computers are grouped into five generations according to the main technology used to build them.

Behavioural objectives

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

1. Name the early calculating devices that came before electronic computers.
2. Name the five generations of computers.
3. State the main technology used in each generation.
4. List the features of first-, second- and third-generation computers.
5. Describe fourth- and fifth-generation computers.

What is the history of the computer?

The history of the computer is the story of how counting tools developed into modern electronic machines.

• Computer: an electronic device that accepts data, processes it by following instructions, stores it and gives out information.
• Generation: a stage in computer development marked by a major change in the technology used to build the machine.

What were the early calculating devices?

Early calculating devices were mechanical tools that helped people count and calculate before electronic computers existed.

• Abacus: a frame with beads used to add, subtract, multiply and divide. It is one of the oldest counting tools.
• Pascaline: a mechanical adding machine built by Blaise Pascal in 1642.
• Analytical Engine: a design by Charles Babbage for a machine that could store data and follow instructions. He is called the father of the computer.
• Ada Lovelace: she wrote instructions for Babbage’s engine and is regarded as the first programmer.
• Punched-card machine: Herman Hollerith used punched cards to process census data in 1890.

What are the generations of computers?

There are five generations of computers: first, second, third, fourth and fifth.

What are first-generation computers?

First-generation computers were the earliest electronic computers, built with vacuum tubes.

• Beginning: electronic machines, distinct from mechanical computers, evolved about 1945.
• Examples: ENIAC, EDVAC and UNIVAC. UNIVAC is a good example of this generation.

Computers of this generation were characterised by the following:

1. They used vacuum tubes.
2. They were very large and expensive.
3. They were very bulky.
4. They had a low retentive memory.
5. They generated a lot of heat.
6. They were programmed in machine language.

What are second-generation computers?

Second-generation computers replaced vacuum tubes with discrete transistors.

• Capability: they were limited but more advanced than first-generation computers.
• Example: IBM 1401.

Features include:

1. They were more reliable than the first generation.
2. They could perform calculations faster.
3. They had a more efficient storage facility.
4. They generated less heat than first-generation computers.
5. They were smaller and used less power than first-generation computers.

What are third-generation computers?

Third-generation computers used Integrated Circuit (IC) technology and Small Scale Integration (SSI).

• Integrated circuit: many tiny electronic parts placed on one small chip.
• Software: more sophisticated capabilities, such as multi-programming, multi-processing and operating systems as resource managers.
• Example: IBM System/360.

The following can be noted in third-generation computers:

1. Faster input and output.
2. Increased storage capability.
3. Increased processing capability.
4. Ability to display pictures and musical sound.

What are fourth-generation computers?

Fourth-generation computers used Large Scale Integration (LSI) and Very Large Scale Integration (VLSI).

• Beginning: they appeared in about 1975.
• Performance: higher speed, larger storage capacity and better performance than the third generation.
• Microprocessor: a whole processor placed on a single chip, which made personal computers possible.
• Examples: desktop computers, laptops and other personal computers.

What are fifth-generation computers?

Fifth-generation computers are built around Artificial Intelligence (AI).

Computers of this category were built around the following aims:

• Supercomputers: computers that could operate in the range of 10 billion instructions per second.
• Human-like abilities: capacities like sight and hearing, and the capability to simulate human thought, for example robots.

How do the five generations compare?

The table below sets the five generations side by side.

Evaluation

1. Name one example of a first-generation computer.
2. State three characteristics of first-generation computers.
3. Which technology marked the third generation of computers?
4. Which generation of computers makes use of artificial intelligence?
5. What does VLSI mean?

Assignment

1. State what the first generation used as its circuitry, list four features of second-generation computers, and state two features of third-generation computers.