Computer systems Flashcards
What is the CPU?
The CPU carries out all the instructions in a computer
What are registers?
Registers are memory locations within the processor itself
Temporary
they work at extremely fast speeds without causing abottleneck
PC
Program counter- keeps track of the memory location of the line of machine code being executed.
contains the address of the next instruction that is needed to be fetched /carried out
MDR
The memory data register stores the data that has been fetched from or stored in memory
copy of MAR
contains data currently used by the processor
MAR
the memory address register stores the address of the data or instructions that are to be fetched from or sent to
copied from PC
address of memory location
may be address of next instruction
CIR
Stores the most recently fetched instruction waiting to be decoded and executed
ACC
the accumulator stores resultsof calculation made by the ALU
Data bus
carries data from one register to another
Address bus
carries the location of the register where the data is going
Control bus
sends control signals from the control unit to the rest of the processor
ALU
arithmetic logic unit carries out calculation and logical decisions results are stored in the acc
Control unit
sends out signals to co -ordinate how the processor works
it controls how the data moves around the part of the CPU and how it moves between the CPU and memory
Instructions are decoded in the control unit
What is an input device?
An input device allow data to be entered into a computer
Examples: keyboards,mice,microphone,scanners ,joystick
What is an output device?
An output device allow information to be retrieved form a computer
Examples:printer,speakers.monitors,
What is magnetic storage?
uses a magnetisabile material disk drives magnetic tape
