Monday, February 4, 2013

Basics of a Computer.

Part 1: via Amna Javed.

Hardware Components of Computer

Computer is an electronic device that takes input, process it and gives an output termed as an information.

Computer is such a device capable of performing logical operations, calculations and high speed computing at a rate of billions times faster than human beings. It is a collection of multiple devices working together as a single unit.

Peripheral devices:

Peripheral devices are just hardware items for your computer like a mouse, keyboard, printer, monitor, microphone, speakers, game controller, webcam, and other input/output devices on the outside of your computer.

Common peripheral devices are printers, scanners, disk drives, tape drives, microphones, speakers and cameras.

Input Devices:


Mouse is an input devices which performs certain action by pointing and clicking. It’s a pointing device which controls the movement of the pointer on the screen to make selection on the screen. The mechanism at the bottom of a mouse detects the movement of the mouse.

Keyboard is the most common input device which inputs instructions by pressing a particular key. A standard keyboard has 101 or 105 keys. Alphanumeric keys consists of alphabets, numbers, punctuations marks and symbols. Control keys are used alone or with a combination of other keys to perform certain actions dependinG on its use. The most frequently used control keys are CTRL,SHIFT,ALT, ESC etc. Function keys are used perform certain actions which varies from program to program. These keys are F1,F2 – F12. Navigation keys are used for moving around in documents or web pages and editing text. They include the arrow keys, HOME, END, PAGE UP, PAGE DOWN, DELETE and  INSERT. Numeric keypad consists numeric keys for the direct entry of numbers. 

Central Processing Unit:

Central processing unit is the brain of computer made of electronic circuits.CPU interprets instructions to the computer, performs all the logical and arithmetical calculations and delivers output to the output devices.


Computer memory consists of two memories: RAM and ROM. Random access memory (RAM)  is the main memory of computer. Operating system is loaded in RAM during the boot up process. It is a volatile memory i.e. the data stored in it is lost when the computer is turned off. Read only memory (ROM) is the permanent memory of the computer. It is programmed by the programmer. This memory can only be read cannot be edited or modified by the user. It is non-volatile memory i.e. the data stored on it is not lost even if the computer is turned off.

Output Devices:

Output devices are those devices which gives you the result or information after processing the input. Output is categorized into two types i.e. softcopy and hardcopy. Softcopy is the output that can only be seen but cannot be touched e.g. the output viewed on the monitor screen. Hardcopy is the output which can e seen as well as be touched e.g. the output printed by the printer on a paper.

Storage devices:

In a computer, storage is the place where data is held in an electromagnetic or optical form for access by a computer processor. The most commonly used storage devices are floppy disk, hard dis and CD-ROM drives. These devices are known as secondary storage devices.

Disk Storage Mechanism:

The disk’s storage locations are divided into pie-shaped sections called sectors
The sector is capable of holding 512 bytes of data.
A typical floppy stores data on both sides and has 80 tracks on each side with 18 sectors per track.

Hard Disk:

Another form of auxiliary storage is  a hard disk. A hard disk consists oof one or more rigid metal plates that allow data to be magnetically recorded on the surface of the platters. The hard disk platters spin at a high rate of speed, typically 5400 to 7200 revolutions per minute (RPM) Storage capacities of hard disks for a personal computer ranges from 10 GB to 120 GB.

Compact Disks:

A compact disc  (CD) is a small, portable, round medium made of molded polymer (close in size to the floppy disk for electronically recording, storing, and playing back audio, video, text, and other information in digital form. It uses a laser technology to read and write data. The capacity of a CD is 650 MB of data.

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