CONCEPTS OF COMPUTER HARDWARE SYSTEM

Computer is an electronic devices that has the compability to accept data through an input devices, apply series of arithmetic and logical processes on the data and give out information through an output device at a very high speed. Today's computers are electronic and digital. Digital computers operate on data, numeric or otherwise, represented as digits, usually in the binary system.

A digital electronic computer system consists of the hardware and software.

Computer Hardware System

The hardware refers to the physical equipments and electronic devices that makes up a visible computer. An example is the computer printer. Hardware can be divided into two: Central Processing Unit (CPU) and the Peripherals.

1. The CPU is responsible for all processing     that the computer does and it consists of       Main Storage, Arithmetic and Logical Unit     (ALU)  and the Control Unit.

• Main Storage is used for storing data to be processed as well as the instructions for processing them.
• ALU is the unit for arithmetic and logical operations.
• Control unit ensures the smooth operations of the other hardware units i.e. it fetches, interprets instructions and issues commands to the units responsible for executing the instructions.

2. The Peripherals are responsible for feeding data into system and for collecting information from the system. The peripherals are in three categories: Input devices, Output devices and Auxiliary storage devices.

• An Input Device is used for supplying data and instructions to the computer.  Examples of input devices are mouse, keyboard, card readers,  scanner, etc.
• An Output devices is used for obtaining information (or result of processed data) from the computer. Examples are printer, visual display unit, etc.
• Auxiliary storage is used for storing information on a long term basis. Examples are Magnetic Disk(floppy, hard, compact), Magnetic tape, etc. Auxiliary storage are also called secondary storage or backing stores. There are two categories of auxiliary storages, these are serially accessible and directly(randomly) accessible. In a serially accessible auxiliary storage, data can only be stored or retrieved in a serial order while data can be accessed or stored randomly or serially on directly accessible auxiliary storage.