✅ 1. Systems Architecture

Question 1

Answer 1

Question 2

Difference between hardware and software

Answer 2

Hardware are the physical components that make up a computer
Software is the programs that run on a computer system and control the hardware

Question 3

What is the purpose of the CPU?

Answer 3

The purpose of the CPU is to fetch data or instructions from the main memory, process them and execute them

Question 4

What is the function of the Arithmetic Logic Unit?

Answer 4

The function of the Arithmetic Logic Unit is to carry out mathematical and logical operations

Question 5

Give examples of what the operations performed by the ALU include

Answer 5

Boolean logic operations such as AND, OR, NOT
Addition & Subtraction

Question 6

What is the function of the Control Unit?

Answer 6

The control unit contains a clock which sends control signals to other components within the CPU at fixed intervals in order to direct operations and synchronise activity between components within the CPU

Question 7

What is cache?

Answer 7

• Cache is a very small and very fast amount of memory built within the processor
• It stores data and instructions the processor frequently uses, so that it can be accessed faster than accessing them from RAM

Question 8

What are Registers?

Answer 8

Registers are a small piece of memory within the CPU that can hold one instruction or address

Question 9

What are the 4 types of registers?

Answer 9

• Program Counter (PC)
• Memory Address Register (MAR)
• Memory Data Register (MDR)
• Accumulator

Question 10

What is the function of the Memory Address Register (MAR)?

Answer 10

The MAR stores the address of the data to be retrieved from, and the address where the data will be written to

Question 11

What is the function of the Memory Data Register (MDR)?

Answer 11

The Memory Data Register (MDR) stores the data or instruction that is fetched from
memory. It also stores the data that will be written to memory.

Question 12

What is the function of the program counter?

Answer 12

The function of the program counter is to:

• Store the address of the next instruction to be fetched from memory
• Increment in each fetch-execute cycle by 1

Question 13

What is the function of the Accumulator?

Answer 13

The accumulator stores the result of the calculation from the ALU

Question 14

Fetch - Decode - Execute Cycle

Answer 14

1. The PC holds the address or location of the next instruction to be run
2. The address of the instruction to be fetched is copied into the MAR
3. The instruction which is stored at the location held in the MAR, is fetched from the main memory, and then copied into the MDR
4. The instruction in the MDR is then decoded by the Control Unit and executed by the ALU
5. The result of the ALU calculation is then sent to the Accumulator, where the result is stored
6. The value in the PC is then incremented by 1 so that it now points to the next instruction which has to be fetched
7. The process is then repeated

Question 15

What factors affect the performance of the CPU?

Answer 15

• Clock Speed
• Cache Size
• Number of Cores

Question 16

What is clock speed?

Answer 16

Clock speed is the number of fetch-execute cycles or instructions that are executed per second

Question 17

What does a clock speed of 1GHz mean?

Answer 17

1 GHz is 1 billion cycles per second

Question 18

How does increasing the cache size affect the performance of the CPU?

Answer 18

Increasing the cache size means:
- More data and instructions can be stored closer to the CPU
- Data can be accessed faster than accessing it from the RAM
- So more cache improves the performance of the CPU

Question 19

The fastest cache is the one with the ____________ capacity

Answer 19

The fastest cache is the one with the smallest capacity

Question 20

Describe L1 cache

Answer 20

L1 cache is the cache with the fastest transfer rate, but a very small capacity

Question 21

Describe L3 cache

Answer 21

L3 cache is the cache with the slowest transfer rate, but a very big capacity

Question 22

Why can too much cache be bad?

Answer 22

Too much cache can be bad because it will take longer to find the instructions in cache

Question 23

Is cache expensive?

Answer 23

Yes

Question 24

How does increasing the number of cores improve system performance?

Answer 24

• Increasing the number of cores means that there are more processors
• Which means that each processor can execute a separate instruction at the same time
• So the computer is able to multi-task and parallel processing can take place

Question 25

Why may the number of cores not always increase the CPU performance?

Answer 25

The software may be designed to run on one core and not take advantage of multiple cores

Question 26

What is an embedded system?

Answer 26

An embedded system is a computer system that is built into another system/device

Question 27

What are the characteristics of embedded systems?

Answer 27

• Embedded systems are designed perform very limited and specific tasks (or one-few dedicated functions)
• Embedded systems are not built for general-purpose
• They can be built using less powerful hardware
• Usually stored as firmware on a single chip
• Usually cannot be updated

Question 28

Give 4 examples of embedded systems

Answer 28

• Dishwasher
• Microwave
• Fridge
• Washing Machine