Lesson 3:Computer Components

Introduction
Just like the Human body, the computer is made up of different components, all of which are very important for the overall effective functioning of its system. The word computer refers to a system composed of many components. A computer system has both hardware and software components. This lesson discusses these components and helps the learner to understand the role and contribution of each component to the effective working of the system.

Lesson Content
A computer is made up of the following components: the hardware and the soft ware.

Hardware
 * The hardware are the parts of computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry, keyboards, monitors, case and drives (floppy, hard, CD, DVD, optical, tape, etc...).
 * Other extra parts called peripheral components or devices include mouse, printers, modems, scanners, digital cameras and cards (sound, colour, video) etc... Together they are often referred to as a personal computers or PCs.
 * Central Processing Unit (CPU) - Though the term relates to a specific chip or the processor a CPU's performance is determined by the the rest of the computers circuitry and chips.
 * Keyboard - The keyboard is used to type information into the computer or input information.
 * Disk Drives - All disks need a drive to get information off - or read - and put information on the disk - or write. Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term 'disk' and 'drive' are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files - or software - and the drive is the mechanism that runs the disk.
 * Mouse - Most modern computers today are run using a mouse controlled pointer. Generally if the mouse has two buttons the left one is used to select objects and text and the right one is used to access menus. If the mouse has one button (Mac for instance) it controls all the activity and a mouse with a third buttons can be used by specific software programs.

One type of mouse has a round ball under the bottom of the mouse that rolls and turns two wheels which control the direction of the pointer on the screen. Another type of mouse uses an optical system to track the movement of the mouse. Most desktop computers use a monitor with a cathode tube and most notebooks use a liquid crystal display (LCD) monitor. To get the full benefit of today's software with full colour graphics and animation, computers need a color monitor with a display or graphics card.
 * Monitors - This Visual Display Unit (VDU) shows information on the screen when you type. This is called outputting information. When the computer needs more information it will display a message on the screen, usually through a dialog box. Monitors come in many types and sizes from the simple monochrome (one colour) screen to full colour screens.
 * Printers - The printer takes the information on your screen and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser.
 * Scanners- Scanners allow you to transfer pictures and photographs to your computer. A scanner 'scans' the image from the top to the bottom, one line at a time and transfers it to the computer as a series of bits or a bitmap. You can then take that image and use it in a paint program, send it out as a fax or print it.
 * Memory - Memory can be very confusing but is usually one of the easiest pieces of hardware to add to your computer. It is common to confuse chip memory with disk storage. An example of the difference between memory and storage would be the difference between a table where the actual work is done (memory) and and a filing cabinet where the finished product is stored (disk). To add a bit more confusion, the computer's hard disk can be used as temporary memory when the program needs more than the chips can provide.
 * Random Access Memory or RAM is the memory that the computer uses to temporarily store the information as it is being processed. The more information being processed the more RAM the computer needs.

Rachel ogbe 15:36, 26 February 2007 (CET)