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Computer System

The Components of a computer system are:

Hardware Software Users

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System Unit: CPU , main memory drives, and the power supply.

Input Devices: Keyboard & mouse

Output Devices: monitor

Peripherals: any piece of hardware that is connected to a computer. Used to perform special input and output tasks. Printer, scanner & modem

The Major components of a PC are:

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ALUALU CUCU

MemoryMemory

Central Processing UnitCentral Processing Unit

Secondary StorageSecondary Storage

Output Output DevicesDevices

Input Input DevicesDevices

Chapter 2: Hardware

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Hardware

1) Central Processing Unit (CPU):Chip called Microprocessor. Follows the instructions of the software to process data producing information.

Parts of a CPU: ALU( Arithmetic & logic unit): The ALU consists of electronic

circuitry to perform arithmetic operations (addition, subtraction, multiplication and division), logical operations (and, or, not, …) and to make some comparisons (less-than, equal, … etc.)

Registers or Immediate Access Memory Control Unit

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2.2. Input DevicesInput Devices

Translate data from form that humans understand to one that the computer can work with. Most common are keyboard and mouse

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Input DevicesInput Devices Keyboard Mouse Trackball Touch Pad Touch Screen Light pen Scanners: FlatBed, SheetBed & HandHeld

Stationary Scanners & Drum Scanners Joystick Microphone Disk Drives Digital Camera Video Camera

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Pieces of equipment that translate theprocessed information from the CPU

into a form that humans Can understand.

3.3. Output DevicesOutput Devices

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Output Devices Monitors: Video Display Units (VDU)

Types of monitors:Cathode Ray Tube (CRT)A Flat-Panel Display (Liquid Crystal Display LCD)Characteristics of monitors:Colors, Size, Resolution: Pixels, Multiscan :screen can display different Resolution

LED Displays: Light Emitting Diodes

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Printers Daisy Wheel: Slow & noisy, produces carbon copies Dot matrix printersReasonably quick and very cheap to run. Colour is limited

and requires a change of cartridge. Very Noisy. Inkjet printers

Better results that a dot matrix Can be purchased fairly cheaply, even the colour models Quieter than a dot matrix.Slower than a Laser Printer Replacement ink cartridges are quite expensive making running costs high Lower quality than a Laser Printer

Laser printersHigh quality printouts Very quick and cheap to runExpensive to buy especially colour

Plotters Speakers Speech Synthesizers Removable Media Projectors

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Ahmad MahaSuha

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