CS: P1 Revision

CS: P1 Revision

1. Registers

   • Program Counter
     • holds the memory address of the next instruction to be fetched from main memory
   • Memory Address Register
     • holds the address of the current instruction that is to be fetched from memory, or the address in memory to which data is to be transferred
   • Memory Data Register
     • holds the contents found at the address held in the MAR, or data which is to be transferred to main memory
   • Accumulator
     • holds the data being processed and the results of processing
   • Current Instruction Register
     • holds the instruction that is currently being decoded and executed

2. Clock Speed

   • Frequency is more operations within a given amount of time
   • E.g. A CPU with a clock speed of 3.2 GHz executes 3.2 billion cycles per second

3. Cores

   • Each unit in a processing unit is called a core
   • A core contains an ALU , control unit and registers
   • CPUs with multiple cores have more power to run multiple programs at the same time

4. RAM

   • Random-access memory
   • A form of computer data storage which stores data and machine code that's currently being used

5. Virtual Memory

   • Enables data that is in the RAM and not currently being used to be transferred to the hard disk
   • Frees up room in the RAM for other programs and data
   • Virtual memory makes a computer run slower
     • Performance can be increase by increasing size of RAM, reducing the need for virtual memory