the computer system (hardware) part 1

The Computer System

An Introduction

System a group of interrelated components working together toward a common goal by accepting inputs and providing outputs in an organized transformation process

http://www.nytimes.com/2008/01/13/business/13digi.html?ex=1200978000&en=0b6cc3ab4da6a22b&ei=5070&emc=eta1

System Examples:

Digestive System


Computer System consists of computers and computer-controlled devices that process data by executing programs.


Computer SystemDevices:


Computer SystemComponents:

HardwaresSoftwares


The Computer System

Hardware

Hardware the physical component of computer system

4 Types:Input DevicesOutput DevicesStorage DevicesProcessing and Control Devices


Input Devices used to enter data into a computer and to give commands to manipulate the data

physical equipment which read or translate data into electronic impulses, which can be understood by the computer


Input Devices1. Keyboard2. Mouse3. Trackball4. Touchpad5. Light Pen6. Joystick7. Touchscreen


Input Devices8. Voice Input9. Barcode Readers10. Pen Based System11. Scanners12. Optical Mark Recognition13. Optical Character Recognition


Input Devices14. Smart Cards15. Optical Cards 16. Video Input Device17. Electronic Camera18. Sensors19. Magnetic Ink Character Recognition


Keyboard the standard input device

2 Major Types:Qwerty KeyboardDvorak Keyboard


KeyboardQwerty Keyboard

- invented by Christopher Sholes in 1868


KeyboardDvorak Keyboard

- invented by Augustus Dvorak in 1936


Keyboard3 Partitions:

Functional KeysAlphanumeric KeysNumeric Key Pad


Mouse Device that is rolled about on a desktop to direct a pointer on the computer’s display screen

Mouse Pointer


Mouse2 Major Types:

MechanicalOptical


Mouse5 Mouse Actions:

ClickDouble ClickDrag and DropRight ClickPoint


Trackball a movable ball, on top of stationary device, that is rotated with the fingers or palm of the hand


Touch Pad a graphics tablet which consists of a flat drawing surface and a pointing tool that functions like a pencil

The tablet turns the pointer’s movements into digitized data that can be read by special computer programs


Touch Pad


Light Pen looks like an oversized writing pen

attached to an electronic cord and requires special software support.

Works by sensing the sudden small change in brightness of a point on the screen when the electron gun refreshes that spot.


Light Pen


Joystick is a pointing tool that consists of a

vertical handle like a gearshift lever mounted on a base with one or two buttons


Touch Screens a video display screen that has been

synthesized to receive input from the touch of a finger


Voice/Audio Input convert a person’s voice into digital

signals


Barcode Readers are photoelectric scanners that read

the vertical stripes that comprise the bar-code


Pen Based System use a pen-like stylus to enter

handwriting and marks into a computer


Scanner convert text, photographs, and

black-and-white or color graphics into computer-readable form


Optical Mark Recognition uses a device that reads pencil

marks and converts them into computer-usable form


Optical Character Recognition

uses a device that reads special preprinted characters and converts them into machine-readable form


Smart Cards

looks like a credit card but contains a microprocessor and memory chip


Optical Cards

are plastic, laser recordable, credit card size cards used with an optical card reader


Video Input

the signals that come from a VCR or a camcorder must be converted to digital form through special video card installed in the computer


Electronic Camera

captures images in electronic form for immediate viewing


Sensors

collects specific kinds of data directly from the environment and transmits it to a computer


MICR

computer systems of the banking industry can magnetically read checks and deposit slips using magnetic ink character recognition (MICR) technology


MICR

Another familiar form of magnetic data entry is the magnetic stripe technology that helps computers read credit cards


MICR


Output Devices convert the information that comes out of a computer (bits and bytes) into screen images, print or other forms


Output Devices1. Monitor2. Printer3. Projector4. Speakers


Monitor primary output device

vary greatly in the sharpness and quality of the images they produce


MonitorTypes:

Monochrome

Flat Panel Monitor


MonitorTypes:EGA (Enhanced Graphics Adapter)

640 X 350 Pixel Screen.

VGA (Video Graphics Array) 640 X 480 Pixel Screens

SVGA (SUPER VIDEO GRAPHICS ARRAY) 1,024 X 768 Pixel Screen


MonitorTerms: soft copy

screen output, intangible

scan rate number of times the screen is refreshed

(60 times / second)

Dot pitch the amount of space between the dots


the computer system (hardware) part 1

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