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Computer hardware refers to the physical parts of a computer, i.e., the tangible components of a computer e.g. mouse, monitor, keyboard, etc.
As in Fig 1.1, computer hardware is normally grouped according to the basic operations the computer performs; hence there are: -
o Input Devices
o Processing devices
o Output devices
o Storage devices
o Communication devices
Input Device: From Person to computer
Information processing is usually hidden from the user. He / she is able to see the input / output. Input devices include the following: -
This is used to type letters, numbers, and special characters. The computer responds to the input from the keyboard by displaying the typed characters on the screen at the position of the line (in some cases a rectangle) called a cursor. It looks almost the same as a typewriter.
Some keys – cursor (arrow) keys, the Delete key, the Enter key function keys (f-keys) and others, send special commands to the computer, and these may have different names or meanings on different computer systems.
Many computer users today use their keyboard mostly for entering text and numeric data. For traditional keyboard functions such as sending commands and positioning the cursor, they use a mouse.
The mouse is designed to move the pointer around the screen and point to specific characters or objects. As the mouse moves, the pointer on the screen mimics the mouse motion. The mouse has more than one buttons that can be used to send signals to the computer, conveying the messages such as;
o “Activate the selected tool”
o “Select all the text between these two points”
What you can do with the mouse
o Slide across your desktop – a pointer echoes the movement of the mouse
o Click – press the left mouse button while the mouse is stationary
o Double click – press the left mouse button twice within a second.
o Right click – press right mouse button while the mouse is stationary.
o Drag – move the mouse while holding the button down
Wand Readers and Optic character recognition (OCR)
When wand readers use light to read alphabetic and numeric characters written in a specially designed typeface found in many sales tags and credit cards slips. When these wand readers are used to recognize words and numbers, the computer is performing optical character recognition.
A scanner is a device that can make a digital representation of any printed image. Scanners convert photographs, drawings, charts, and other printed information into a form that can be stored and manipulated in a computer.