Hardware Flashcards
The Purpose of the CPU ?
The purpose of the CPU is to process data and carry out instructions.
Describe the arithmetic logic unit (alu)
Where the CPU performs the arithmetic and logic operations. Data is passed to the ALU to allow the required calculations to be carried out. The results of any calculations are then sent to be stored in a register. There are two parts to the ALU:
- The arithmetic part, which deals with calculations, e.g. 1 + 2 = 3
- The logic part, which deals with any logical comparisons, such as the comparison of two numbers, e.g. 2 > 1
Describe the control unit
The control unit manages how data is processed by the CPU.
It manages how the CPU and other components communicate, for example communicating with a printer or USB device.
It executes all instructions provided by programs.
It informs the ALU, IAS along with input and output devices how to respond to instructions from a program
Describe immediate access store - (memory)
The Central Processing Unit must have access to data as fast as possible. Each piece of data is stored in the random access memory chip so that the CPU can retrieve data immediately. Each memory location has a unique address assigned to it.
Describe register
It is normally used for a specific purpose, where data or control information is temporarily stored.
Some registers are used in the fetch-execute cycle while others may be used by the program being executed.
Registers are much faster to access because they have to be accessed so often.
What is the fetch - execute cycle?
Explains the basic steps the CPU takes to process an instruction. It is in 5 stages
What is the first stage of the fetch - execute cycle?
- Program Counter
It is the program counters job to have the address of the first and each subsequent instruction of the fetch-execute cycle.
2nd stage of the fetch execute cycle and what does MAR stand for
- Memory Address Register (MAR)
The memory address register stores the ADDRESS of current instruction or data being executed.
3rd stage of the fetch execute cycle and what does MDR stand for
Memory Data Register (MDR)
When the instruction is fetched the memory data register temporarily holds it. All data from memory to CPU goes via MDR.
4th stage of the fetch execute cycle and what does IAR stand for
Instruction Address Register (IAR)
Also referred to as : Instruction Register
The Instruction Address Register holds the current instruction to be executed.
5th stage of the fetch execute cycle
Arithmetic Logic Unit (ALU)
This is a vital part and end of the fetch-execute cycle. The ALU will carry out the logical part of the instruction for example a calculation.
What is clock speed measured in?
Cycles per second.
What does 1 cycle per second equal?
1 hertz
What is a typical desktop computer’s clock speed?
3000 million cycles per second or 3GHz.
What effect does a CPU with a high clock speed have?
Makes it look as though the computer is completing multiple tasks at once.
