Module 1: Using Computers, LANs, and Email for Academic Coursework

Components of a Computer

A computer is a complex machine that is put together from many components. When you look at a computer for the first time you most likely notice the major pieces of the machine: the monitor, the keyboard, the mouse, and the computer case (sometimes called the CPU or box).

The monitor contains the screen, which displays visual data. The screen is in a plastic case which also contains some controls to maintain the picture quality and a cable to connect to the computer case. There are several common types of monitor--the most common being the cathode ray tube (CRT) monitor and the liquid crystal display (LCD) monitor. The CRT monitor is normally found in desktop machines and the LCD in laptop or notebook machines. The most important feature of the monitor is its size, which is measured in inches diagonally across the screen. Monitors usually come in 9, 12. 15, 17 and 21, inch sizes. Also important in a monitor is the resolution. This is measured in dots per inch or pixels per inch. The higher the number of dots per inch, the better the screen resolution.

The keyboard is designed to allow the user to type data into the computer so that it can be manipulated and saved. There are a number of different keyboard types. The most common English keyboard is called "qwerty". The most common French keyboard is called "azerty". Some keyboards are built to be ergonomic. In other words, they are designed to reduce stress on the computer user's fingers and wrists.

The mouse is a tool that helps the user manipulate data contained in the computer and to tell the computer what to do through mouse commands (clicking on icons and menus). There are many kinds of computer mouse. Most come with two buttons but some have one (MacIntosh) and some contain more that two. Some computer mice come with scroll wheels to help with scrolling on a computer screen. The newer mice are now wireless and laser. This means that the do not need to be physically connected to the computer and that the mouse has no moving parts on the bottom.

The computer case contains the fundamental components of the computer. These include the motherboard, Read Only Memory (ROM), Random Access Memory (RAM), Central Processing Unit (CPU) and Drives. The motherboard is the data, power and transport system of the computer. Various circuit cards (e.g. Ethernet cards) and chips (e.g. RAM) plug into the motherboard and draw power from this board. The ROM is built into the motherboard and contains permanent instructions. These instructions enable the computer to "boot" and begin working when the power is turned on. The RAM is the short term memory of the computer. This memory is volatile in that, unlike the ROM and hard disk, when the power is turned off, the RAM memory is emptied. The CPU is the workhorse of the computer. It is the component that executes programs and commands and coordinates all of the components of the computer. The most common types of CPU are manufactured by Intel (called Pentium); IBM and Motorola, (called G4 and G5) and AMD (called Athelon). The drives--hard drive, floppy drive, CDRom drive and DVD drive are sometimes called secondary storage (the ROM and RAM is primary storage). These drives are designed to store data that can be read by the computer and normally be written back to the drive (saved). Some CD and DVD drives are read only.

Peripherals are components of a computer system that are usually optional. They add functionality to the computer system and plug into the computer with a cable. Examples of common peripherals are printers, scanners, joysticks and digital cameras. Peripherals are sometimes categorized as input and output devices. This refers to the direction the data is moving. If the device moves data into the computer it is an input device such as a mouse, microphone or scanner. If the device moves data out of the computer it is an output device such as a monitor, printer or speakers. Some components of a computer can be either built into the computer case and are called internals or be peripheral devices or external. Hard disk drives and modems are examples of components that can be either internal or external.