Input and Output - computer notes

Input System- An input device is a peripheral or piece of computer hardware equipment, which is used for providing data and controlling signals to an information processing system (Computer).


1. Keyboard: It is human interface device, which is represented as a layout of buttons. Each button or key could be used to input linguistic character to a computer for particular functions.
2. Pointing Devices (Mouse & Trackball): These are any human interface devices that allow users to input spatial data to a computer. Eg: mouse, trackball, Glidepad

3. Game Devices: The motion of cursor is controlled by joystick or arrow buttons (Game Pad)
4. Pen Input: It is especially used in Personal Digital Assistant (PDA). It is used for Data input, Pointing Device, and Command Gesture etc.
5. Touch Screen: The touchscreen enables the selection by just touching the screen.
6. Digitizers and Graphic Tablet: The Tablets have Special Command for the conversion of drawing and photos.
7. Page Scanner: It works like copy machine and captures whole image for converting to the digital image.
8. Hand Scanner: It can move across document or picture. It can capture only a section of a page or a large image.
9. Bar Codes: It is used at the retail shops to track inventory and calculate the sale at the checkout counter.
10. Optical Character: It uses letters or special characters that are especially shaped t be easy for the machines to read.

Output System- An Output System is computer hardware equipment, which is used to communicate the result of data processing system.

1. Printer: A printer prints the content on the monitor onto a paper. The speed of a printer could be measured in character per second (cps), line per minute (lpm), and page per minute (ppm). The quality of prints can be measured in DPI (Dot Per Inch).
There are two types of printer: Impact Printer
a) Dot Matrix Printer
b) Daisy Wheel
c) Chain & Band Printers

Non Impact Printer
a) Inkjet Printer
b) Thermal Printer
c) Laser Printers

2. Screen (Monitor): The Monitor is a screen on which words, numbering, and graphic could be seen. The device that displays computer output has various names comprising
a) Screen
b) Monitor
c) Visual Display Terminal
d) Cathode Ray Tube
e) Visual Display Unit
f) Liquid Crystal Display

a) Monochrome
b) Color
c) CRT
d) LCD
e) Plasma Screens



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