COMPUTER

3. TYPICAL COMPONENTS OF COMPUTER SYSTEM

Logical Organization of a Computer

The logical organization of a computer is based on its definition.

The computer hardware comprises of the following Units:

•       Input unit

•       The central processing unit (CPU) (Control unit and Arithmetic & logic unit)

•       Memory unit 

•       Output unit

Input Unit: means by which data is entered into the computer that includes all input device or means through which computer accepts data from users via the input devices. Examples include the keyboard, mouse, joystick, trackball and scanner.

KEYBOARD: We use a pencil or pen to write in a book. We use chalk or a marker to write on the board in class. We can‘t use any of these to write on a computer, so we use the keyboard to enter information and instructions to the computer.

KEYS OF KEYBOARD

Computer keyboards include keys that are designed to perform specific tasks. These keys enable the user to perform complex tasks easily when using the application. For example, many applications use a function key to access online help for the user.

Types of Computer Keyboard

There are four major types of Computer Keyboard used worldwide depending on their size and numbers of keys are QWERTY, AZERTY, DVORAK and QWERTZ

Keyboard keys consist of

•       Alphabetic keys

•       Numerical keys

•       Symbols

•       Functional keys

•       Extra keys

Alphabetic keys contain alphabets from A-Z & a-z

Numerical keys contain numbers 0-9

Symbols keys contain many symbols like!, @, #, $, % etc

Functional keys contain f1-f12, design for special purpose will discuss latter.

Extra keys contain Esc, Alt, Ctrl, Backspace, Enter etc