System Architecture

Question 1

What are the stages of the FDE cycle?

Answer 1

Stage 1: Fetch
Stage 2: Decode
Stage 3: Execute

Question 2

What is RAM?

Answer 2

The main memory

Question 3

What happens in the fetch stage of the fetch-execute cycle?

Answer 3

• The program counter is checked as it holds the address of the next instruction to be executed.
• This address is used by the MAR to fetch the instruction needed from RAM and bring it back to the CPU
• The address in the program counter is incremented to point at the next instruction

Question 4

What happens in the decode stage of the fetch-execute cycle?

Answer 4

The CU decodes the instruction and works out what needs to be done

Question 5

What happens in the execute stage of the fetch-execute cycle?

Answer 5

The instruction is executed with could be
- Going back to the memory and grabbing some data
- Performing a calculation
- Storing information back into main memory

Question 6

What is clock speed measured in?

Answer 6

Hertz (Hz)

Question 7

1 hertz (Hz) means…

Answer 7

…one cycle per second

Question 8

CPU stands for

Answer 8

Central processing unit

Question 9

What is an input device?

Answer 9

A device used to enter information into a computer

Question 10

What is an output device?

Answer 10

A device that presents data from the computer

Question 11

What is a storage device

Answer 11

A piece of computer equipment on which information can be stored

Question 12

What is the CPU?

Answer 12

The part of the computer that fetches, decodes and executes instructions and manages the rest of the hardware

Question 13

Describe The Von Neumann Architecture

Answer 13

• Instructions are fetched, decoded and executed once at a time
• Instructions and data are held together in the same memory space

Question 14

What does the address bus travel between?

Answer 14

MAR to RAM

Question 15

What does the data bus travel between?

Answer 15

MDR and RAM

Question 16

What does the control bus do?

Answer 16

Carry signals to coordinate all the computer’s activities

Question 17

What does CU stand for?

Answer 17

Control unit

Question 18

What does the CU do?

Answer 18

• Decode instructions
• Send control signals to control how data moves around the CPU

Question 19

What does ALU stand for?

Answer 19

Arithmetic logic unit

Question 20

What does the ALU do?

Answer 20

Carry out mathematical and logical operations

Question 21

What are special purpose registers

Answer 21

Small amounts of high speed memory used to store small amounts of data needed in proccesing

Question 22

What does MAR stand for?

Answer 22

Memory address register

Question 23

What does the MAR do?

Answer 23

Holds the address of where data is to be fetched or stored

Question 24

What does MDR stand for?

Answer 24

Memory data register

Question 25

What does the MDR do?

Answer 25

Holds data fetched from or to be written to the memory

Question 26

What does the program counter do?

Answer 26

Holds the address of the next instruction

Question 27

What does ACC stand for?

Answer 27

Accumulator

Question 28

What does the accumulator do?

Answer 28

Hold the results of calculations performed by the ALU

Question 29

What is the cache?

Answer 29

Memory that provides **fast access** to **frequently used instructions** and **data**

Question 30

What are the factors affecting the speed of the CPU?

Answer 30

- Clock speed - Number of cores - Cache size

Question 31

What did John Von Neumann invent in 1945?

Answer 31

The first computer with a stored program

Question 32

What is a fixed program?

Answer 32

A program that cannot be updated without rewiring or redesigning

Question 33

What is a core

Answer 33

A complete copy of the CPU

Question 34

What are embedded systems?

Answer 34

Computer systems with a dedicated function within a larger mechanical or electrical system

Question 35

What are the advantages of multi core processors?

Answer 35

- Cores can work on separate tasks at the same time (multitasking) - The cores can work together (parallel processing)

Question 36

How does a bus transport data across the motherboard?

Answer 36

With electrical conductors

Question 37

What is another name for the FDE cycle?

Answer 37

The instruction cycle

Question 38

What is clock speed?

Answer 38

The frequency at which the internal clock generates pulses

Question 39

What does the internal clock do?

Answer 39

Synchronises components by generating pulses at a constant rate

Question 40

Why does cache size affect the speed of the CPU?

Answer 40

The larger the cache, the more data can be stored without having go back to RAM