Hardware

Hardware

1. The Central Processing Unit

   • Uses of CPU
     • Carries out 3 actions: Fetch-Decode-Execute
       • Fetch
         • Collects the data
       • Decode
         • This is where the data that was fetched is decoded
       • Execute
         • This is where the action commanded is performed
     • Clock speed and cores
       • Determines how fast data is processed
         • cores can complete millions of actions at once
         • The more cores the faster data is processed
           • Slow clock speed means data is being processed slowly
           • If you had a quad core processor it would multiply the amount of hertz by 4
       • Measured in hertz (Hz)
         • One Hz = 1 instruction each second
       • Kilohertz (KHz)
         • Megahertz (MHz)
           • Gigahertz (GHz)
             • 1 billion cycles per second
           • 1 million cylces per second
         • 1000 cycles per second
     • Cache
       • Stores data that might need to be used again
       • Quicker than main memory
       • Stores very little
   • Heats up so must be cooled by a fan
   • Contains 'control unit' and 'arithmetic logic unit
   • Brain of Computer
   • Processes (Fetch-Decode-Execute Cycle)