Computer Literacy Chapter 2

Terms Computer refers to a device that accepts input, processes data, stores data, and produces output Processor (CPU) Information Processing Cycle

Terms (contd.) Generally, what does a computer do? Turns data into information Data – collection of raw unprocessed fact, figures, and symbols (useless) Information – data that is organized, meaningful, and useful

Software The set of computer programs that enables the hardware to perform different tasks

The set of programs you use on a computer to help you carry out tasks Application Software The set of programs you use on a computer to help you carry out tasks

System Software The set of programs that enables your computer’s hardware devices and application software to work together.

Hardware The parts you actually touch. Examples: System unit the box that contains the central electronic components of the computer Peripheral Devices Those devices such as monitors and printers that are connected to the computer

Together the system unit and peripheral devices perform four main functions They enable the computer to: input data process data output data store data and information

Input Devices Examples: Enables you to enter data (text, images, and sounds) and instructions into the computer. Examples:

Are all keyboards the same? QWERTY Keyboard The name comes from the first six letters in the top-left row of the alphabetic keys Originally designed for typewriters and was meant to slow the typist to prevent jamming.

Dvorak keyboard Putt the most commonly used letters in the English language on “home keys,” or on the middle row of the keyboard. This design reduces the distance your fingers travel for most keystrokes, thereby increasing typing speed.

Virtual Laser Keyboard Projects the image of a keyboard on any surface, and sensors detect the motion of your fingers as you type on a desk Data is transmitted by a Bluetooth device

Optical Mouse: uses an LED light beam to track movement Laser Mouse: uses a laser light beam to track movement (achieves greater sensitivity)

Wireless Mouse: Trackball Mouse: Scanner:

Touchpad: Digital Pen: Webcam:

Output Devices Monitors CRT – Cathode Ray Tube LCD – Liquid Crystal Display

What factors affect the quality of an LCD monitor? Resolution: The clearness or sharpness of the image The higher the resolution, the sharper and clearer the image will be. Monitor resolution is listed as a number of pixels. A high-end monitor may have a maximum resolution of 1600 x 1200. Meaning it contains 1600 vertical columns with 1200 pixels in each column Viewing Angle: An LCD’s viewing angle, which is measured in degrees, tells how far you can move to the side of the monitor before the image quality degrades to unacceptable levels.

Contrast ratio: Brightness: Response Time: The measure of the difference in light intensity between the brightest white and the darkest black colors that the monitor can produce. Brightness: A measure of the greatest amount of light showing when the monitor is displaying pure white. Measured as candelas per square meter. Response Time: The measurement of the time it takes for a pixel to change color. The lower the response time, the smoother moving images will appear on the monitor.

Things to consider when choosing a printer: Printers Impact Printers: Have tiny hammer-like keys that strike the paper through an inked ribbon, thus making a mark on the paper. Non-Impact Printers: Spray ink or use laser beams to transfer marks onto the paper. Things to consider when choosing a printer: Speed Memory Resolution (dpi) Cost of the printer Color output Cost of consumables