3. Types of Processor

Question 1

Define the stored program concept

Answer 1

Machine code instructions are fetched and executed serially by a processor that performs arithmetic and logical operations

Question 2

Where is the program that needs to be executed held according to the stored program concept?

Answer 2

Main memory

Question 3

What happens to machine code instructions in the stored program concept?

Answer 3

Fetched 1 at a time, decoded and executed in the processor

Question 4

What basic components are included in the Von Neumann architecture?

Answer 4

1. ALU
2. Single CU
3. Registers
4. Memory units

Question 5

How are data and instructions stored and transferred in the Von Neumann architecture?

Answer 5

1. Stored in the same memory

2. Transferred via the same data bus

Question 6

Is the word length of all the memory the same or different?

Answer 6

It is the same, regardless of whether it holds data or instructions

Question 7

What concept is the Von Neumann architecture built on?

Answer 7

The stored program concept

Question 8

How are data and instructions stored in Harvard architecture?

Answer 8

In physically separate memories, more commonly used with embedded Digital Signal Processing (DSP) systems

Question 9

When is using separate memories useful?

Answer 9

1. When memories have different characteristics. E.g. instructions may be read-only, data may be read-write
2. When optimising the size of individual memory cells and their buses. E.g. instruction memory can be designed to be larger so larger word sizes can be used for instructions

Question 10

Is Von Neumann or Harvard architecture cheaper?

Answer 10

Von Neumann

Question 11

Is Von Neumann or Harvard architecture faster and why?

Answer 11

Harvard: data and instructions can be fetched in parallel rather than competing for the same bus like in Von Neumann

Question 12

Name 5 DSP applications

Answer 12

1. Audio and speech signal processing
2. Sonar and radar signal processing
3. Biomedical signal processing
4. Seismic data processing
5. Digital image processing

Question 13

Name 4 embedded systems

Answer 13

1. Navigation systems
2. Traffic lights
3. Aircraft flight control systems
4. Simulators

Question 14

Does Von Neumann architecture contain large programs?

Answer 14

No, Harvard architecture does but Von Neumann programs can be optimised in size

Question 15

Where is Von Neumann architecture used?

Answer 15

Conventional PCs, severs and embedded systems with only control functions

Question 16

What are contemporary processors?

Answer 16

Processors that use a combination of Von Neumann and Harvard architecture

Question 17

Describe a design of a contemporary processor

Answer 17

Using Von Neumann architecture when working on data and instructions in main memory
Using Harvard architecture to divide cache into instruction cache and data cache

Question 18

What does RISC stand for?

Answer 18

Reduced Instruction Set Computer

Question 19

What does CISC stand for?

Answer 19

Complex Instruction Set Computer

Question 20

Name the main features of a RISC processor

Answer 20

1. Small instruction set
2. Each instruction is approximately 1 line of machine code
3. Only takes 1 clock cycle for every instruction

Question 21

Name the main features of a CISC processor

Answer 21

1. Large instruction set
2. Instructions built on the hardware
3. Use as few lines of assembly code as possible

Question 22

Describe the compilers in RISC and CISC processors

Answer 22

RISC - Compiler needs to do more work to translate high level code into machine code
CISC - Compiler does less work

Question 23

Describe the RAM in RISC and CISC processors

Answer 23

RISC - More is required to store code

CISC - Less RAM since code is shorter

Question 24

Which of RISC and CISC allows for pipelining?

Answer 24

RISC - Each instruction takes one clock cycle

Question 25

Which of RISC and CISC uses specialised instructions?

Answer 25

CISC - Even though only a few of them are used

Question 26

Which of RISC and CISC is the more popular processor design?

Answer 26

RISC

Question 27

Where is CISC used?

Answer 27

Micro-controllers and embedded systems

Question 28

What is a co-processor?

Answer 28

An extra processor used to supplement the functions of the primary processor

Question 29

Name 3 examples of a function for a co-processor

Answer 29

1. Performing floating point arithmetic
2. Graphics processing
3. Digital Signal Processing

Question 30

What are multi-core CPUs able to do?

Answer 30

Distribute workload across multiple CPU cores, achieving significantly higher performance

Question 31

How does a parallel system work?

Answer 31

Distributing workload using a single core by using threading

Question 32

Is a multi-core or parallel system better for larger projects?

Answer 32

Multi-core systems perform better