Computer Systems

Computer Systems

1. Hardware

   • Input devices
     • Keyboard
     • Mouse
   • Output devices
     • Screen
     • Printer

2. Software

   • Powerpoint
   • Publisher

3. CPU

   • Von Neuman architecture
     • CPU with instructions and data together, with 1 data bus and 1 control bus
   • Harvard architecture
     • CPU with instructions and data seperate, with 2 data buses and 2 control buses
   • Clock speed
     • Measured in Hertz
       • 1 hertz = 1 instruction processed/second
       • 1GHZ = 1 billion hertz
     • Number of instructions executed/second
   • No. of cores
     • = no. of processors
   • ALU
     • Performs arithmetic & logic operations
   • Buses
     • Data bus
       • Carries data between CPU and memory - it's bi-directional
     • Control bus
       • Carries control signals
     • Address bus
       • Carries addresses from the processor to main memory - it's uni-directional
   • CU

4. Embedded computer systems

   • A computer system within a device
   • E.g. Stairlift / traffic lights
   • Suited to one particular job
   • Affordable

5. Secondary storage

   • All of the storage except ROM and RAM is secondary