1.8 Representation of information:-

Floppy Disk Storage devices

1.9 Input, Output and input/output Devices

The concept of input and output is basic to computers. The primary job of a computer is to process information, and to do that you need a way to get information in and a way to get the processed information out. The devices that help you get information into the computer are called input devices. The devices that help you get the processed information out are called output devices.

Some common input devices are the:

There are many input devices that you can use to get information into your computer. The two most common are the keyboard and the mouse.

• Keyboard

• Mouse

• Microphone

• Scanner

• Storage Device (CD-ROM, floppy disk, hard disk)

Keyboard: - You use the keyboard to type information into your computer or access commands. There are many different styles of computer keyboards, but they all provide the same basic functionality. If you look at a keyboard, you will notice some of the basic key types as illustrated below.

Mouse: - You use a mouse to translate your hand movements into movements of an on-screen pointer. By controlling the pointer with the mouse, you are able to input information and instructions by selecting, rather than by typing. A mouse is most commonly used with graphical user interfaces, like the Windows operating system and the applications that work with it.

You can perform the following tasks using a mouse:

• Move around in a document

• Select and change information

• Choose items from a menu

• Start programs

• Change the size and position of windows on the screen

• Move text and pictures

A mouse on a PC usually has two or three buttons on it. By clicking the buttons on a mouse, you tell the computer to take a specific action. In most computer programs that utilize a mouse, the way you click the buttons sends different signals to the computer. For example, a single click on a mouse button may mean that you want to change the position of the cursor on the screen. On the other hand, a double-click (two quick clicks in succession) may mean that you want to start a program.

Some common output devices are the:

• Monitor

• Speakers

• Printers

If you want a printed copy of your information you can send it to a printer. If you want to play a sound file you will most likely hear those sounds through speakers.

The main output device on your PC Day 2 computer is the monitor. Monitors are also called screens or displays. There are many different types of monitors and the main differences between them are:

• Screen size

• Graphics and color display

• Image quality

Screen size  A monitor’s screen size is measured diagonally. Your PC Day 2 monitor is 15 inches.

Graphics & Color Display Most computer tasks these days involve the manipulation of text as well as graphics. To view the full range of colors that some graphics were intended to contain you’ll need a monitor that can display colors. A monitor that can display 256 colors will suffice for most graphic presentations, but the majority of monitors being manufactured, including your PC Day 2 monitor, can handle millions of colors. In order to display anything, monitors require a graphics adapter board. Graphics adapter boards are mostly responsible for the quality of the image being displayed.

Image Quality An image’s display quality largely depends on the graphics adapter board installed in your computer. The graphics adapter resides in your system unit and is the component that drives the monitor.