Ochieng’ Okoth COMPUTER SCIENCE CONCEPTS
COMPUTER HARDWARE
Hardware is the name given to all physical devices and components which make up a
computer system.
This includes the central processing unit (C.P.U) and the other peripheral units, therefore a
computer system is basically made of six components
This consist of:
1. Input devices
2. Control unit
3. Main memory C.P. U
4. Arithmetic and logic unit (A.L.U)
5. Output devices
6. Backing storage
Input devices
These are devices used to enter data or instructions into the computer. This is any machine
that feeds data in a computer, e.g keyboard, scanner, mouse, light pens, digitizers.
I. Keyboard
Its an input device consisting of a set of type writer like keys that enables you to enter data
into a computer.
The IBM enhanced keyboard have one on one keys arranged into six groups as follows: -
I. Alpha numeric keys
This part is similar to a type writer. The letters are arranged as in a type writer and the
arrangement is called QUERTY
It also has numbers (0-9) punctuation keys and other characters. e.g @ and a few additional
keys with special functions. e.g tab, caps lock, enter key, backspace, space bar.
II. Modifier keys
These are used to modify the input of other keys by pressing another key by holding down a
modifier key e.g Shift, Control and Alt keys.
III. Numeric keys
This is located at the right of the keyboard and looks like a calculator.
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COMPUTER HARDWARE
Hardware is the name given to all physical devices and components which make up a
computer system.
This includes the central processing unit (C.P.U) and the other peripheral units, therefore a
computer system is basically made of six components
This consist of:
1. Input devices
2. Control unit
3. Main memory C.P. U
4. Arithmetic and logic unit (A.L.U)
5. Output devices
6. Backing storage
Input devices
These are devices used to enter data or instructions into the computer. This is any machine
that feeds data in a computer, e.g keyboard, scanner, mouse, light pens, digitizers.
I. Keyboard
Its an input device consisting of a set of type writer like keys that enables you to enter data
into a computer.
The IBM enhanced keyboard have one on one keys arranged into six groups as follows: -
I. Alpha numeric keys
This part is similar to a type writer. The letters are arranged as in a type writer and the
arrangement is called QUERTY
It also has numbers (0-9) punctuation keys and other characters. e.g @ and a few additional
keys with special functions. e.g tab, caps lock, enter key, backspace, space bar.
II. Modifier keys
These are used to modify the input of other keys by pressing another key by holding down a
modifier key e.g Shift, Control and Alt keys.
III. Numeric keys
This is located at the right of the keyboard and looks like a calculator.
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