Flashcards in Components of a Computer Deck (117)
Arithmetic Logic Unit
Carries out calculations and logic (Comparisons of binary)
Control Unit is a register in the CPU that controls and co-ordinates the activity of the CPU. Control signals are sent along the control bus between the control unit and the other components of the computer.
Registers are small storage locations used to hold data temporarily. They have high read and write speeds.
stores the address of the next instruction
Memory Address register (MAR)
stores the address of instructions and data that need to be fetched from memory
Memory Data register (MDR)
stores the data which is to be sent or fetched from memory
Current instruction register
stores the actual instruction that is being decoded
stores the result of calculations made by the ALU
generates and detects interrupts
the communication channels between the CPU and the memory and other components.
A one directional bus that transmits memory addresses that are used as operands in programming instructions, so that data can be retrieved from main memory
A bi-directional path for moving data and instructions between system components
A bi-directional bus to transmit command, timing and specific status information between system components
collective term for address, data and control bus
fetch decode execute cycle
1. The address of the next instruction is copied from the PC to the MAR
2. The fetch signal is sent across the control bus. The content of the MAR are transferred across the address bus.
3. The contents of the memory location stored in the MAR are sent across the data bus and stored in the CIR
4. the PC increments by 1
The contents of the CIR are sent to the CU and divided. The Opcode tells you the instruction to be carried out and the operand stores the address of any data which might be needed, the operand is sent to the MAR and the data is fetched from memory and stored in the MDR
The appropriate instruction/ opcode is carried out on the data/ operand
program branch reason
occurs due to an if statement, function, procedure call or loop.
program branch result
the next instruction held in the PC is not carried out
Indicates the number of instructions the CPU can process per second.
Clock speed Unit
Hertz (usually gigahertz)
Positives of increasing clock speed
you can carry out more instructions in a given time; improved performance
Negatives of increasing clock speed
more heat generated meaning computers must be cooled (either with heat sync/fan or water/oil cooling)
Special high speed memory used by a computer. Stores frequently used data and instructions.
Positives of increasing cache size
less time fetching data; improved performance
negative of increasing cache size
Multiple CPUs working on a single computer
positives of multiple cores
may speed up processing