Computer System
Senior 1 · ICT
Computer System
Lesson 2 of 5
18 min
Let's begin
ENIAC, one of the first electronic computers, was finished in 1945. It weighed about 27 tonnes, filled a large room, used about 18,000 glass vacuum tubes and needed 150 kilowatts of electricity. The chip inside a modern phone fits on your fingertip and is hundreds of thousands of times more powerful. This lesson traces how that happened and names the main types of computers in use today.
People have used tools to help them calculate for thousands of years, such as the abacus. In the 1830s Charles Babbage designed the Analytical Engine, a mechanical computer that could be programmed with punched cards, and Ada Lovelace wrote about how it could be programmed. It was never finished, but its ideas are found in every computer today.
Each generation began when a new electronic part made computers smaller, faster, cheaper and more reliable. The dates are approximate.
| Generation | Main technology | Features | Example |
|---|---|---|---|
| First (1940s to mid-1950s) | Vacuum tubes (valves) | Huge, very hot, used a lot of electricity, broke down often. Programmed in machine code with switches, cables and punched cards. | ENIAC (1945), UNIVAC I (1951) |
| Second (late 1950s to mid-1960s) | Transistors (invented in 1947) | Smaller, faster, cheaper and more reliable. Early programming languages such as FORTRAN and COBOL. | IBM 1401 (1959) |
| Third (mid-1960s to early 1970s) | Integrated circuits (ICs): many transistors on one small silicon chip | Smaller again; keyboards and screens; operating systems let many programs run. | IBM System/360 (1964) |
| Fourth (1971 to today) | Microprocessors: a whole processor on one chip | Personal computers, laptops, smartphones; networks and the internet. | Intel 4004 chip (1971), today's PCs and phones |
| Fifth (today and the future) | Artificial intelligence and many processors working in parallel | Computers that understand speech, recognise images and learn from data. | Voice assistants, chatbots, self-driving car research |
| Type | Description | Used for |
|---|---|---|
| Supercomputer | The fastest and most powerful computers, with thousands of processors working together. Very expensive and fill large rooms. | Weather forecasting, climate research, space science, designing medicines. |
| Mainframe | Large, very reliable computers that serve hundreds or thousands of users at the same time. | Banks, national censuses, airlines, large companies processing huge numbers of transactions. |
| Minicomputer | Mid-sized, cheaper than a mainframe. Popular from the mid-1960s to the mid-1980s; similar machines today are called midrange servers. | A single department, factory control, a university laboratory. |
| Microcomputer | A computer built around a microprocessor, used by one person at a time. Also called a personal computer (PC). | Desktops, laptops, tablets and smartphones used at home, school and work. |
Tip
Generations: Very Tiny Items Make AI. Vacuum tubes, Transistors, Integrated circuits, Microprocessors, Artificial intelligence.
Family, from biggest to smallest: Super, Mainframe, Mini, Micro.
Name the main electronic part used in each of the first four generations.
Solution: First: vacuum tubes. Second: transistors. Third: integrated circuits. Fourth: microprocessors.
Give two problems of first-generation computers.
Solution: Any two: very large; produced a lot of heat; used a lot of electricity; vacuum tubes burned out often, so they broke down; hard to program.
What is the difference between an integrated circuit and a microprocessor?
Solution: An integrated circuit is any chip holding many transistors. A microprocessor is a special integrated circuit that holds a whole processor (CPU) on one chip.
Which type of computer would a national population census office use to process the records of every household, and why?
Solution: A mainframe, because it can store and process huge numbers of records reliably and let many staff work on them at the same time.
Remember
Sources and credits
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
