Central Processing Unit

What is it?

The CPU ( Central Processing Unit ) is the part of a computer that is commonly referred to as the 'brain' of a computer. The CPU is also known as the processor or microprocessor. The CPU is responsible for executing a sequence of stored instructions called a program. It is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output operations specified by the instructions.

What it does

The CPU (Central Processing Unit) – which is also called microprocessor or processor – is in charge of processing data. How it will process data will depend on the program. The program can be a spreadsheet, a word processor or a game: for the CPU it makes no difference, since it doesn’t understand what the program is actually doing. It just follows the orders (called commands or instructions) contained inside the program. These orders could be to add two numbers or to send a piece of data to the video card, for example.

When you double click on an icon to run a program, here is what happens:

1. The program, which is stored inside the hard disk drive, is transferred to the RAM memory. A program is a series of instructions to the CPU.
2. The CPU, using a circuit called memory controller, loads the program data from the RAM memory.
3. The data, now inside the CPU, is processed.
4. What happens next will depend on the program. The CPU could continue to load and executing the program or could do something with the processed data, like displaying something on the screen.

What's Inside a CPU?


In the movie E.T. (1983), aliens build an interplanetary communicator device. Core of the toy "Speak & Spell" is used to communicate this is TMC 2081 from Texas Instruments and the Voice Synthesier first chips.