Computer

(1).What is a Computer: 

 

 

 

An electronic device that stores, retrieves,and processes data, and can be programmed with instructions. A computer is composed of hardware and software, and can exist in a variety of sizes and configurations.

 

(2).Hardware and Software:

 

Hardware: 

 

The term hardware refers to the physical components of your computer such as the system unit, mouse, keyboard, monitor etc.

 

Software:

 

The software is the instructions that makes the computer work. Software is held either on your computers hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is
loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required. 

 

(3).Types of Computers:

 

Mini and Mainframe Computers:

Very powerful, used by large organisations such an banks to  control the entire business operation. Very expensive!

 

 Personal Computers:

Cheap and easy to use. Often used as stand-alone computers or in a network. May be connected to large mainframe computers within big companies.

 

(4).Hardware Components:

 

Input Devices -- "How to tell it what to do“

- A keyboard and mouse are the standard way to interact with the computer. Other devices include joysticks and game pads used primarily for games.

Output Devices -- "How it shows you what it is doing"

- The monitor (the screen) is how the computer sends information back to you. A printer is also an output device. 

 

INPUT DEVICES:

 

• The Mouse:

Used to ‘drive’ Microsoft Windows .

 

• The Keyboard:

  
  
  The keyboard is still the commonest way of entering information into a computer.

   

• Tracker Balls:

   

      An alternative to the traditional mouse and often used by  graphic designers.

 

• 
  Scanners:

A scanner allows you to scan printed material and convert it into a file format that may be used within the PC.

• 
  Touch Pads:

   

 
A device that lays on the desktop and responds to pressure.

• 
  Light Pens:

   

     Used to allow users to point to areas on a screen.

• 
  Joysticks:

   

     Many games require a joystick for the proper playing of the game. 

 

  OUTPUT DEVICES:

• 
  VDU:

   

The computer screen is used for outputting information in an understandable format.

 

• 
  Printers:

   

There are many different types of printers.
In large organizations laser printers are most commonly used due to the fact that they can print very fast and give a very high quality output.

• Plotters:

   

A plotter is an output device similar to a printer, but normally allows you to print larger images.

• 
  Speakers:

   

Enhances the value of educational and presentation products.

• 
  Speech synthesisers:

   

Gives you the ability to not only to display text on a monitor but also to read the text to you .