What is a Computer?¶

Learning Objectives:

• Understand that computers process data.
• Understand that a program is a sequence of instructions for a computer.
• Understand what a Turing machine is and how it is used in determining what we can and can not compute.
• Understand that computers can’t solve all problems.
• Understand what a programming language is.

A computer is a device that can perform actions on input (which is also called data). The actions are specified by a program, which is a sequence of instructions. A computer doesn’t really even have to be electronic. Did you know that there were female computers? The Harvard computers were hired to do astronomical calculations. Computer was a job title, like waiter or doctor.

Figure 1: The Harvard Computers of 1913

Computers today are electronic, but it’s possible to build a computer with light, or DNA, or even TinkerToys. All computers manipulate data based on instructions.