SYSTEMS ARCHITECTURE

Question 1

What is a Computer?

Answer 1

An electronic device that takes input, processes data, and delievers output

Question 2

What is the purpose of a CPU?

Answer 2

The centeral processing unit fetches, decodes and executes instructions

Question 3

What is the fetch stage of a CPU?

Answer 3

Fetch the next instruction from main memory (RAM) and bring it back to CPU

Question 4

What is the decode stage of a CPU?

Answer 4

Inspect the instruction and work out what it is that needs doing

Question 5

What is the execute stage of a CPU?

Answer 5

Carry out the instruction

Question 6

What is the purpose of an ALU?

Answer 6

The arithmetic logic unit is responisble for carrying out arithmetic calculations and making logical decisions

Question 7

What is the purpose of the CU?

Answer 7

The control unit send signal sto control how the data moves around the CPU.

Question 8

What is the purpose of the cache?

Answer 8

The cache provides fast access to frequently used data and instructions

Question 9

What is the purpose of the registers?

Answer 9

The registers are tiny, super fast peices of onbaord memory inside a CPU.

Each have a specific purpose

Question 10

What did Von Neumann design?

Answer 10

He designed computers with stored programs

Question 11

What is a stored program?

Answer 11

A stored programmed computer has changable progams

Question 12

What are the key characteristics of the Von Neuman architecture?

Answer 12

C - CPU
I - Internal clock
O - Onboard cache
S - Single CU
A - ALU

Question 13

How is data stored in memory?

Answer 13

Both instruction and program data are stored in the same memory in binary form

Question 14

What is the program counter?

Answer 14

The PC always holds the address of the next instruction to be executed in memory

Question 15

What is the MAR?

Answer 15

The memory address register holds the address of where data is to be fetched from or stored into

Question 16

What is the MDR?

Answer 16

The memory data register holds the data fetched from or to be written to memory

Question 17

What is the accumulator?

Answer 17

Holds the results of the calculations

Question 18

Describe the fetch-execute cycle in Von Neuman’s architecture.

Answer 18

The program counter (PC) is checked as it holds the address of what needs to be executed

The memory address register (MAR) then fetches the instrution paired to the address from main memory (RAM) and brings it to memory data register (MDR)

The PC will then increment the address to point to next instruction

Now the instruction is in CPU, the control unit (CU) will decode the instruction to see what has to be done

Lastly the instruction is executed

Question 19

What 3 factors affect the performance of the CPU?

Answer 19

Cache size
Clock speed
Nmber of cores

Question 20

What is Clock sped and how does it affect the performance of the CPU?

Answer 20

Clock speed is the number of cycles per second measured in Hertz (Hz)

The faster the clock ticks, the more you can fetch and execute instructions vice versa

Question 21

What is Cache size and how does it affect the performance of the CPU?

Answer 21

The cache is a temporary storage of data located near to the CPU. It stores recent data and instructions and is much quicker getting items from than RAM.

Is quicker than getting instructions and data from memory BUT cache is limited and has less storage –> affects CPU’s overal performance.

Question 22

What is a core and how do the number of them affect the CPU’s performance?

Answer 22

A core is a complete copy of a CPU.

CPUs with more cores have more power to run multiple programs at once .

CPU cores have to communicate to eachother which takes time so more cores = more time. PLUS, many programs are not designed to make maximum use of every core

Question 23

What is an embedded system?

Answer 23

An embedded system is a computer system with a dedicated function within a larger mechanical and electrical system

Question 24

Give some examples of an embedded system.

Answer 24

Washing Machine
Microwave
Oven
Fridge
Apollo guidance computer
Traffic lights
etc