Components of a

Computer System

J. Stover, CSD-HS

A computer is an electronic device that is programmed to accept data (input), process it into useful information (output), and store it for future use (storage).

The processing function is under the control of a set of instructions (software); we will explore this later.

What is a Computer

The CPU is the brain of the computer. The CPU consists of electronic circuits that interpret and execute instructions; it communicates with the input, output, and storage devices.

The CPU, with the help of memory, executes instructions in the repetition of machine cycles.

CPU

A computer system has two basic parts◦ hardware ◦ software.

The equipment associated with a computer system is the hardware.

Computer hardware is responsible for performing four basic functions◦ Input◦ Processing◦ Output◦ Storage.

HARDWARE

Input devices◦ send data to the central processing unit◦ Send instructions to the central processing unit.

Output Central processing unit ◦ executes computer instructions. ◦ Memory holds data and programs temporarily.

4 Primary Components: Computer System

Processing Output devices ◦ make processed data available to the user.

Secondary Storage Secondary storage devices◦ store data and programs permanently.

In order to function properly, a computer system must have all four types of hardware: input, processing, output, and storage.

4 Primary Components: Computer System cont’

A machine cycle consists of four steps:◦ The control unit fetches an instruction and data

associated with it from memory. ◦ The control unit decodes the instruction. ◦ The arithmetic/logic unit executes the instruction. ◦ The arithmetic/logic unit stores the result in

memory.

Machine Cycle