Lesson Notes — Computers Was Once a Job Title & Turing Machines / Turing Test

Course 1: Computer Literacy / Unit 2: PC Hardware & System Architecture / Lesson 4: Computers Was Once a Job Title & Turing Machines / Turing Test

Lesson overview

Before there were electronic computers, a computer was a person whose job was to do calculations by hand. Understanding that history helps you see what a modern computer really is: a machine that does computation, which means following steps to turn input into a result.

From human computers to machines

• Human computers: For centuries, teams of people worked out tables of numbers for navigation, astronomy, and later aircraft and space flight. Some of the best known were the women who calculated trajectories for NASA.
• Babbage’s engines: In the 1800s, Charles Babbage designed mechanical calculating machines, including the Analytical Engine, which was planned to use punch cards for instructions. Ada Lovelace wrote notes on it that included a method many call the first computer program.
• Vacuum tubes: Early electronic computers of the 1940s used glass vacuum tubes as switches. They were large, hot, and used a lot of power. Transistors later replaced them and made computers smaller and cheaper.
• Binary code: Computers represent everything using just two states, 1 and 0.

Alan Turing

• In 1936, Alan Turing described the Turing machine, an imaginary machine that reads and writes symbols on a tape by following simple rules. It showed that a machine following steps could carry out any computation that can be described that way.
• During World War II, Turing worked on decryption, breaking enemy secret codes, as part of the British effort at Bletchley Park.
• In 1950, he proposed what we now call the Turing test. In it, a person chats with an unseen partner, which might be a human or a machine. If the person cannot reliably tell which is which, the machine passes. It is an early idea in artificial intelligence.

Why this matters

The Turing test is still discussed when people talk about AI chatbots. Many experts argue that sounding human is not the same as understanding, which is a good question to bring to Unit 12.

Check your understanding

1. What did the word “computer” mean before the 1940s?
2. How did vacuum tubes and, later, transistors change the size of computers?
3. Do you think a chatbot that passes the Turing test is really thinking? Give a reason.

Use this lesson’s Key Terms page to build your glossary.