IS revision

IS revision

1. the control unit

   • overall control
   • fetch, excute and decode cycles
   • controls the flow of data

2. the arithmetic logic unit

   • does all calculations contains accumulator
   • completes addition, subtraction, multiplication and division
   • performs logic operations such as AND, OR and NOT

3. the cache

   • very fast
   • slower than the registers
   • Level 1 is the fastest cache, this has the lowest storage though.
   • located inside the CPU
   • Level 2 is slower than level 1 but faster than level 3. it has more storage than level 1 but less than level 3
   • level 3 is the slowest cache, but it has the highest amount of storage

4. register

   • program counter
     • contains the address of the instruction being executed at the current time.
   • accumlator
     • does all simple calculations
   • memory address register(MAR)
     • stores where the data will be stored, ready for when the CPU needs the data
   • memory data register(MDR)
     • stores the data being transferred to and from the immediate access storage.

5. embedded systems

   • embedded systems are built into other devices
   • allows the device to be more efficient
   • As they are dedicated to one task, they are much easier to design and cheaper to produce.

6. Components of a CPU

   • power supply
     • supplies power to the motherboard, optical and hard drives
   • case cooling fan
     • extracts hot air from the inside the case
   • CPU heat sink and cooling fan
     • keeps the CPU at a steady temperature
   • CPU
     • Most important component, process all instructions
   • Optical drive
   • Magnetic drive
   • Solid state drive
   • RAM
     • Volatile storage, only used while the computer is turned on
   • Graphics card