What is a Computer?

A computer is a machine that can be programmed to automatically process information or perform tasks.

The physical parts of the machine (including the parts inside, the case itself, and the devices attached to it) are together referred to as hardware.

The changeable instructions that a computer needs to actually do anything useful are referred to as software, programs, or code.

At its heart, a computer is able to do only one thing: It is able to count to 1. In fact, everything a computer does all boils down to a long string of 1's and zero's, because at it's heart, those are the only numbers a computer can understand. This numbering system that consists only of the numbers 1 and zero is called binary.

In order to do anything more complicated than count to one, a computer needs programming, or code, which consists of instructions that tell the computer how to do various things.

Some code is contained on microchips built into the computer. This code contains very basic instructions that the computer needs to even know that it is a computer and how to address the various devices it contains. The most basic code a computer needs is built right into the processor chip, which is the heart of the computer.

Other code is installed on a computer's hard drive by the manufacturer or user. This code is called software. Software is not a permanent, physical part of the machine. It can be changed as needed, or new software added, to make the computer more useful.

The physical box, tower, half-ball, or other oddly-shaped case on which is mounted the power button that you press to turn on the computer, is properly called the Central Processing Unit, or CPU. But the same term is also used for the processor chip inside, which is a little confusing. So many people just refer to the Central Processing Unit as, for example, the "tower."

All the devices that are attached to the Central Processing Unit (like monitors, printers, scanners, and so forth) are called peripherals.