CPU

CPU

1. Stands for Central Processing Unit

2. What does it do?

   • It is the processor for the computer or the 'brain' of the computer
   • Controls the movement of data and instructions
   • Fetch data and instructions from memory
   • Decodes and executes instructions
   • Performs arithmetic operations such as add and subtract and logical operations such as AND, NOT or OR

3. How does it work?

   • Uses electrical signals to execute the instructions in stored programmes

4. What does the performance of the CPU depend on?

   • Processor speed
   • Bus speed
   • Amount of cache available
   • Number of processor cores

5. Fetch execute cycle

   • The process of fetching the instructions from memory, decoding them and then executing them so that the CPU performs continuously

6. Contains 3 main types of memory

   • Cashe
     • Special high speed memory used by a computer
   • ROM
     • (read only memory)
     • A store for data in the computer that cannot be overwritten. Data in ROM is always available and is not lost when the computer is turned off
   • RAM
     • Main memory of a computer that stores data, applications and the operating system whilst in use
     • Random access memory