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What is hardware? Webster’s dictionary gives us the following definition of the hardware – the mechanical. Magnetic, electronic, and electrical devices composing a computer system.

Computer hardware can be divided into four categories –

  1. input hardware
  2. processing hardware
  3. storage hardware
  4. output hardware



The purpose of the input hardware is to collect data and convert it into a form suitable for computer processing. The most common input device is a keyboard. It looks very much like a typewriter. The mouse is a hand held device connected to the computer by small cable. As the mouse is rolled across the mouse pad, the cursor reaches the desired location, the user usually pushes a button on the mouse once or twice to signal a menu selection or a command to the computer.

The light pen uses a light sensitive photoelectric cell to signal screen position to the computer. Another type of input hardware is optic-electronic scanner that is used to input graphics as well as typeset characters. Microphone and digital camera can be also used to input data into the computer.




The purpose of processing hardware is to retrieve, interpret and direct the execution of software instructions provided to the computer. The most common components of processing hardware are the Central Processing Unit and main memory.

The Central Processing Unit (CPU) is the brain of the computer. It reads and interprets software instructions and coordinates the processing activities that must take place. The design of the CPU affects the processing power and the speed of the computer, as well as the amount of main memory it can use effectively. With a well-designed CPU in your computer, you can perform highly sophisticated tasks in a very short time.

Memory is the system of components of the computer in which information is stored. There are two types of computer memory – RAM and ROM.

RAM (random access memory) is the volatile computer memory, used for creating loading, and running programs and for manipulating and temporarily storing data.

ROM (read only memory) is nonvolatile, nonmodifiable computer memory, used to hold programmed instructions to the system.

The more memory you have in your computer, the more operations you can perform tjhat is the faster it works.




The purpose of storage hardware is to store computer instructions and data in a form that is relatively permanent. Storage hardware serves the same basic functions as do office filing systems except that it stores data as electromagnetic signals. The most common ways of storing data are HARD disk (HDD), floppy disk and CD-ROM.

Hard disk is a rigid disk coated with magnetic material, for storing programs and relatively large amounts of data.

Floppy disk (diskette) – thin, usually flexible plastic disk coated with magnetic material, for storing computer data and programs. There are two formats for floppy disks ‘ 5,25’’ and 3,5’’. 5,25’’ is not used in modern computer systems because of it relatively large size, flexibility and small capacity. 3,5’’ disks are formatted 1,44 megabytes and are widely used.

CD-ROM (compact disk read only memory) is a compact disk on which a large amount of digitized read-only data can be stored. CD-ROMs are very popular now because of the growing speed which CD-ROM drives can provide nowadays.


Date: 2015-01-12; view: 901

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