Hardware

Hardware

1. CPU

   • Control Unit
     • Electrical signals
     • Execute instructions from programs
   • ALU unit
     • Arithmetic and logic operations
   • Cache Memory
     • High speed memory
     • Speeds up execution
     • Most recent memory
   • Fetch-Decode-Execute
     • Fetch from main memory
     • Decode - Execute - Repeat
   • Clock Speed
     • Hertz (Hz) = cycle per second
     • If increased it makes the CPU work faster
       • Reduces lifetime of computer
     • Operating speed
   • CPU Core
     • Dual core
       • 2 CPUs
         • Process more instructions

2. Binary Logic

   • Why are they used?
     • Based on logic cicuits
     • 0 or 1 = True or False
   • Logic Diagrams
     • Opposite
       • NOT
       • Opposite
     • • AND
       • Both
         • 0 UNLESS 1,1
     • • OR
       • Either
         • 1 UNLESS 0,0

3. Memory

   • RAM = Random Access Memory
     • Main memory
     • Volatile
     • Stores data when the computer is on
     • More RAM = more data loaded = better performance
   • ROM = Read Only Memory
     • Non - volatile
     • Stores boot sequence
     • Retains data when computer is off
   • Virtual Memory
     • Used when there is not enough main memory to run programs.
   • Flash Memory
     • memory that retains data in the absence of a power supply.
     • e.g. USB

4. Input and Output Devices

   • Used to get data in and information out
   • Input Devices
     • Keyboard
       • Enter data into computer
       • e.g. QWERTY keyboard, Concept keyboard, Braille
     • Microphone
       • Inputting speech and communication
     • Camera
       • Taking photos or video conferencing
   • Output Devices
     • Monitor
       • Displays images and text
     • Printer
       • Produces physical copies of outputs from computer
       • e.g. 3-D, Ink-jet
     • Speakers
       • Output sound

5. Secondary Storage

   • Stores data and programs when computer is off
   • Magnetic Hard Disk
     • Uses magnetised platters to store data and files
   • Optical Disk
     • Uses lasers to read data to a reflective surface
     • Stores files to be shared/transferred or for backup
     • e.g. CD, DVD
   • Flash Memory/solid state
   • Choosing Secondary Storage:
     • Capacity
     • Speed
     • Portability
     • Durabilty
     • Reliabilty

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