The Computer System The computer is an automatic, electronic device that accepts data or input, which it stores and processes to give output or information What are the functions of the computer system?

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Types of Computers Mainframe Mini Computers Super Computers Micro Computers Personal Computers Embedded Computers Laptops, notebooks, netbooks Palmtop Computers Tablet PC Back to top

Mainframe Computer Back to Types of Computers

Mini Computer Back to Types of Computers

Supercomputer Back to Types of Computers

Micro Computers Back to Types of Computers

Functions of a Computer System INPUT PROCESSING OUTPUT STORAGE Back to top

The Computer System - Again MEMORY CPU INPUT Control Unit (CU) Arithmetic & Logic Unit (ALU) OUTPUT Back to functions

The medium through which data is sent to the computer for processing. Input The medium through which data is sent to the computer for processing. Sources of Input Data from Human users Data from Machines Back to functions

Input Devices Keyboard/Keypad Touch Terminal Graphic Tablet Light Pen Pointing Devices Mouse Trackball Pointing Stick Touchpad **Joystick Touch Terminal Graphic Tablet Light Pen Back to Input

Input Back to Input

Scanning Devices Scanning Facilities Scanner Barcode Reader Input Devices Scanning Devices Scanner Flatbed, hand-held, Drum, Sheet-fed Barcode Reader Scanning Facilities OCR OMR MICR Back to Input

Scanners Back to Input

Digital Still-Shot Camera Digital Video Camera Webcam Smart Card Input Devices Digital Still-Shot Camera Digital Video Camera Webcam Smart Card Biometric Systems Remote Control Sensors Interactive Whiteboards Back to Input

Other Input Devices

Input Devices Audio Input Devices Microphone RFID – Radio Frequency Identification MIDI Back to Input

Audio Input Devices

Gaming Input Joystick Gaming pad Gaming Wheel Light gun Dance Pad Input Devices Gaming Input Joystick Gaming pad Gaming Wheel Light gun Dance Pad Motion Sensing controllers Back to Input

Gaming Input Devices

Output Output is the result of processing. It is the purpose you set out to achieve by using the computer. Output Devices are pieces of equipment that are used to communicate output/information. Types of Output Soft copy Hard Copy Back to functions

Output Devices VDU Printers Microfilm/Microfiche Audio Output Robot/Control Systems Back to Output

VDU – Visual Display Unit The Screen is made up of Pixels Types CRT (Cathode Ray Tube) Flat Panel Display LCD (Liquid Cristal Display) Plasma Display Monitor Characteristics VDU Devices Monitor Multimedia Projector LCD Panel Back to Output

Monitors Back to Output

Monitor Characteristics Monitor Size Display Resolution VGA (640 X 480) – Video Graphics Array SVGA(800 X 600) – Super Video Graphics Array XGA/XVGA (1024 X 768) – Extended Video Graphics Array SXGA (1280 X 1024) – Super Extended Graphics Array UXGA (1600 X 1200) – Ultra Extended Graphics Array QXGA (2048 X 1536) – Quad Extended Graphics Array Back to Output

Monitor Characteristics Image Aspect Ratio Ratio width to height Refresh Rate Number of refresh times/second Video or graphics card or adaptor Links processor and monitor Back to Output

Sound Output Speakers Voice Response Systems Speech Synthesis Headphones Earphones / ear buds Voice Response Systems Speech Synthesis Conversion of text to speech Back to Output

Sound Output Devices

Printers Producer of Hardcopy output Classification 1: Character printers Line Printers Page Printers Classification 2: Impact Printers Non-impact Printers Back to Output

Impact Printers Dot Matrix Daisy Wheel Drum, Chain or Band Printer Braille Printer poster Back to Output

Non – Impact Printers Thermal Laser Inkjet Back to Output

Other Printers Mobile Printers Multifunctional Printers Plotters Pen Plotters Inkjet Plotters Electrostatic Plotters Back to Output

Microfiche/Microfilm (COM) COM – Computer Output on Microfilm/Microfiche Microfilm: Roll of film Microfiche: Sheet of film Back to Output

Robot and Control Systems Processor to Robotic hardware produces physical action and is therefore a type of output. Control Systems uses sensors as input and activates an item of hardware as a result of the input received Back to Output

Storage Media and Devices used to keep data and instructions available for immediate or later use. Categories of Storage Primary (Main Memory) Secondary Units of Storage Back to functions

Primary Storage Also called main memory Memory chips (integrated circuit) is immediate access store and resides in the motherboard RAM Temporary and changeable (volatile) Holds programs and data currently being used Cache High speed static RAM (SRAM) Easier to access than primary memory Speeds up processing Back to Storage

Primary Storage ROM Variations of ROM Chips holding instructions needed for starting up the computer Non volatile (not easily modified) Variations of ROM PROM EPROM EEPROM Back to Storage

Units of Storage – see pg 31 Bit (Binary Digit) Byte Character Word Word length Larger Units Kilobyte Megabyte Gigabyte Terabyte Petabyte Exabyte Zettabyte yottabyte Back to Storage

Secondary Storage Also known as auxiliary or backup storage, keeps data and information even while the computer is switched off Classifications by technology Magnetic Optical ROM Classification by Access type Serial Access Direct Access Back to Storage

Storage Media Magnetic Tapes Magnetic Disks Optical Disks Flash Memory Floppy Disks Hard Disks Optical Disks CD (ROM; R; RW) DVD Blu-Ray Flash Memory Back to Storage

Storage Media Pgs 32 - 37 Magnetic Tapes Magnetic Disks Optical Disks Includes microfilm Magnetic Disks Floppy Disks Hard Disks Access time; tracks, sectors, cylinders Optical Disks CD (ROM; R; RW) DVD Blu-Ray Back to Storage

Storage Devices Optical Disk Drive Tape Drive Connectivity **USB Drive FireWire ` Back to Storage

True / False CPU VDU Back to functions

Arithmetic & Logic Unit (ALU) The CPU Also known as the processor Takes raw data and following instructions, converts it to information Speed is measured in megahertz Consists of the Control Unit and the Arithmetic Logic Unit CPU Control Unit (CU) Arithmetic & Logic Unit (ALU) Back to functions

Directs and co-ordinates all activities within the CPU Control Unit Directs and co-ordinates all activities within the CPU Fetches instructions from memory Decodes the instructions Fetches required data Sends data and instructions to ALU for processing Sends data to main memory after processing

Arithmetic Logic Unit Performs ALL arithmetic and logical functions of the computer

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