Computer Systems Flashcards
What is a register inside the processor?
Registers are memory locations within the processor itself. They work at extremely fast speeds.
What is the program counter?
Keeps track of the memory location of the line of machine code being executed. It gets incremented to point to the next instruction.
What is the memory data register?
Stores the data that has been fetched from or stored in memory.
What is the address register?
Stores the address of the data or instructions that are to be fetched from or sent to.
What is the current instruction register?
Stores the most recently fetched instruction, waiting to be decoded and executed.
What is the accumulator?
Stores the results of calculations made by the ALU.
What is the general purpose register?
Used temporarily to store data being used rather than sending data to and from the comparatively much slower memory.
What are buses?
Are the communications channels through which data can be sent around the computer. A good example is a USB when transferring data between computer and external devices.
Name the buses involved in the fetch decode execute cycle.
Control bus
Data bus
Address bus
What does the data bus do?
Carries data between the processor and memory.
What does the address bus do?
Carries the address of the memory location being read from or written to.
What does the control bus do?
Sends control signals from the control unit.
What is the ALU?
Arithmetic Logic unit, carries out calculations and logical decisions. Results of calculations are stored in the accumulator.
What is the control unit?
Sends out signals to co-ordinate how the processor works. It controls how the data moves around parts of the CPU and how it moves between the CPU and memory. Instructions are decoded in the control unit.
What is clock speed?
A CPU clock speed rate measure the amount of cycles a CPU can perform every second. This is measured in Hertz or GHz.
