Control Unit - Manages execution of instructions by sending control signals to other parts of the processor.
Registers - Storage locations in the processor used for a particular purpose. Temporarily stores data or control information.
ALU - Carries out arithmetic and logical operations.
Bus - A parallel group of wires able to transmit groups of bits together from one component to another.
Control Bus - Carries control signals from the control unit to the other components to allow synchronisation of signals.
Data Bus - Carries data and instructions between components.
Address Bus - Carries memory address where data is be sent to/retrieved from.
Program Counter - Contains the memory address of the next instruction to be executed.
Memory Address Register - Contains the memory address of the location containing either the next piece of data or instruction.
Current Instruction Register - Holds the instruction while it is being decoded and executed.
Memory Data Register - Receives instructions/data from the memory location in MAR.
Accumulator - Holds intermediate results of arithmetic and logical operations carried out by the ALU.
Fetch-Decode-Execute Cycle - Describes the steps carried out by the processor when executing instructions.
Clock Speed - Measure of number of fetch-decode-execute cycles the processor can perform per second.
Cache - Cache is used to store frequently used instructions and data as it is faster to access than RAM.
Core - An individual processing unit, each one contains a separate ALU, control unit and registers.
Von Neumann - Processor architecture that stores data and instructions together in the same memory.
Harvard - Processor architecture that features a separate memory for data and instructions.
CISC - A type of processor that can recognise and use many machine code instructions. As a result the hardware is complex.
RISC - A type of processor that can recognise a small number of machine code instructions. As a result the hardware is simple.
Parallel Processing - A computer carrying out multiple instructions simultaneously to solve a given problem.
Secondary Storage - Non-volatile storage that stores data when not in use by the CPU.
Primary Memory - Storage that can be directly accessed by the CPU.
RAM - Volatile memory that holds data and instructions that are in use.
ROM - Non-volatile memory that holds the boot program. The contents cannot be easily changed or deleted.
Virtual Memory - A section of the hard disk that is used as an extension to RAM.
Magnetic Storage - Stores data by magnetising and de-magnetising parts of a specially coated disc.
Optical Storage - Stores data using pits in a reflective disc that are read using a laser beam.
Solid State - Uses electrically programmable non-volatile flash memory.
Input Devices - Examples include: keyboard, mouse, scanner, microphone.
Output Devices - Examples include: monitor, printer, speakers.
