From counting to computing
A computer is a machine that takes in data, processes it by following instructions, stores it and produces results. Today, computers are in phones, cars, fridges and watches. But the first computers filled whole rooms.
Early calculating machines
| Date | Invention | Inventor |
|---|---|---|
| About 2500 BCE | Abacus | Mesopotamia; later China and elsewhere |
| 1642 | Pascaline, a mechanical adding machine | Blaise Pascal (France) |
| 1804 | Jacquard loom, controlled by punched cards | Joseph-Marie Jacquard (France) |
| 1830s | Analytical Engine design, a programmable mechanical computer | Charles Babbage (England) |
| 1843 | First published computer program (for the Analytical Engine) | Ada Lovelace (England) |
| 1890 | Punched-card tabulating machine for the U.S. census | Herman Hollerith |
Ada Lovelace realized that computers could do more than arithmetic; they could work with music, pictures and symbols. She’s often called the first computer programmer.
The first electronic computers
| Year | Computer | Notes |
|---|---|---|
| 1936 | Alan Turing’s "universal machine" idea | Theory behind all modern computers |
| 1943–1945 | Colossus (UK) | Helped break German codes in World War II |
| 1945 | ENIAC (USA) | Filled a large room, weighed about 27 tonnes, used about 18 000 vacuum tubes |
| 1951 | UNIVAC I | First commercially sold computer in the U.S. |
| 1952 | FERUT (University of Toronto) | One of the first computers in Canada |
These machines used vacuum tubes, glass tubes that worked as switches. They were huge, hot, used lots of power and often burned out.
Shrinking computers
| Invention | Year | Impact |
|---|---|---|
| Transistor | 1947 | Tiny switch replaced vacuum tubes; smaller, cheaper and reliable |
| Integrated circuit (chip) | 1958–1959 | Many transistors on one piece of silicon |
| Microprocessor | 1971 | Intel 4004 put a whole processor on one chip with about 2300 transistors |
| Personal computers | Late 1970s–1980s | Apple II, IBM PC and others brought computers into homes and schools |
| Laptops | 1980s–1990s | Portable computing |
| Smartphones | 2007 onward | Powerful computers in your pocket |
Today’s phone chips contain billions of transistors and are millions of times more powerful than ENIAC.
Moore’s law
In 1965, Gordon Moore predicted that the number of transistors on a chip would double about every two years. This trend held for decades, making computers faster and cheaper.
How computers work
Binary
Computers store everything as binary: just 0s and 1s, like switches being off or on. Each 0 or 1 is a bit. Eight bits make a byte. Letters, numbers, photos, music and videos are all stored as long strings of bits.
| Decimal | Binary |
|---|---|
| 1 | 1 |
| 2 | 10 |
| 5 | 101 |
| 10 | 1010 |
Hardware
Hardware is the physical parts.
| Part | Job |
|---|---|
| CPU (processor) | Carries out instructions; the computer’s "brain" |
| RAM (memory) | Holds data the computer is working on right now |
| Storage (SSD or hard drive) | Keeps files when power is off |
| Input devices | Keyboard, mouse, touchscreen, microphone |
| Output devices | Screen, speakers, printer |
Software
Software is the set of instructions.
- Operating systems (Windows, macOS, Android, iOS) run the computer.
- Apps and programs do specific tasks, like games, word processing or web browsing.
- Programmers write software in programming languages like Python, JavaScript and Scratch.
Computers today
Computers forecast weather, design buildings, control airplanes, help doctors diagnose disease and power the internet. Artificial intelligence uses computers to recognize images, translate languages and answer questions.
Canadian researchers like Geoffrey Hinton (University of Toronto) and Yoshua Bengio (Université de Montréal) helped pioneer the deep learning methods behind modern AI. Hinton shared the 2024 Nobel Prize in Physics for this work.
Common mistakes
- Thinking computers are smart on their own. They follow instructions written by people.
- Thinking computers are new. The ideas go back nearly 200 years.
- Mixing up memory (RAM) and storage.
Try it yourself
- Write your age in binary.
- Write step-by-step "instructions" for making a sandwich. Have a friend follow them exactly. What went wrong?
- Make a timeline of computers from the abacus to the smartphone.
Quick recap
- Computers process data by following instructions.
- Babbage designed and Lovelace programmed early computing ideas in the 1800s.
- Early electronic computers used vacuum tubes and filled rooms.
- Transistors and microprocessors made computers small and powerful.
- Computers use binary; hardware and software work together.