Topic 1 - System architecture

Question 1

What are the four main components of the CPU and what does each one do?

Answer 1

Arithmetic logic unit - ALU - Performs arithmetic operations.
Control Unit - CU - Coordinates the the fetch execute cycle and decodes instructions.
Cache Memory - Small, fast memory that holds frequently accessed items that is faster than RAM.
Registers - Super small and super fast memory locations within the CPU.

Question 2

Name all the registers and what they do.

Answer 2

Memory Address Register (MAR) - Address of where is being fetched / where will write to.
Memory Data Register (MDR) - Instruction or data that has just been fetched or will be written.
Program Counter (PC) - Address of the next instruction to be fetched from memory.
Accumulator - Holds the result from ALU calculations.

Question 3

What happens in the FDE cycle?

Answer 3

In fetch - instructions are fetched from memory using the address in the program counter.
Decode - Instruction is interpreted by the control unit.
Execute - Instruction is carried out.

Question 4

What is clock speed?

Answer 4

The rate at which FDE cycles are carried out measured in GHz.

Question 5

What does an increase in the number of cores do?

Answer 5

If a software allows it, each core can execute an instruction at the same time.

Question 6

What does an increase in cache size do?

Answer 6

More regularly used items can be held, reducing the reliance on slower ram increasing performance.

Question 7

What is nan embedded system?

Answer 7

Computers inside other devices usually simple and have one purpose only.