CPU

Question 1

What’s the purpose of the CPU

Answer 1

Runs the instructions from a program

Question 2

What is Von Neumann architecture

Answer 2

Both program instructions and the data the programs are using are both stored in the same places

Question 3

What are the 2 major components of the CPU

Answer 3

-Control unit
-Arithmetic-logic unit (ALU)

Question 4

What are registers and what are they used for

Answer 4

A very fast memory location in the CPU itself that are used to carry out operations

Question 5

Name the 4 registers in the CPU

Answer 5

-Program counter (PC)
-Memory address register (MAR)
-Memory data register (MDR)
-Accumulator

Question 6

What does the program counter do

Answer 6

Holds the address of the next instruction to be executed

Question 7

What does the memory address register do

Answer 7

Holds the memory address of the current instruction, andthen the data that it uses, so that these can be fetched from memory

Question 8

What does the memory data register do

Answer 8

Holds the actual instruction, and then the data that has been fetched from memory

Question 9

What does the accumulator do

Answer 9

Holds the result of an instruction before it is transferred to memory

Question 10

What does he control unit do

Answer 10

It coordinates and controls all of the activities taking place within the CPU
-It decodes instructions and executes them
-it receives signals from the system clock
-It directs the timing and control of other parts of the CPU

Question 11

What does the arithmetic logic unit do

Answer 11

Where the actual arithmetic operations are done. Also carries out logical operations

Question 12

What is the fetch-decode-execute cycle

Answer 12

The CPU operates by repeating three operations
-FETCH: causes the next instruction and any data involved to be fetched from main memory
-DECODE: decodes the instruction
-EXECUT: the instruction is executed
This process is then repeated…

Question 13

What does the program counter do

Answer 13

Holds the address of the next instruction to be executed

Question 14

What does the accumulator do

Answer 14

Where the arithmetic and logic results are temporarily stored

Question 15

What’s the order

Answer 15

1) The control unit decodes the instruction and decides if the data needs to be fetched
2) If so the MAR is then used to hold the address of the data to be used in the instruction
3) The data is fetched and copied to the MDR

Question 16

What effect the CPU peformance

Answer 16

-Clock speed
-Processor cores
-Cache

Question 17

What is the clock speed

Answer 17

The amount of cycles per second measured in hertz (Hz). Therefore the faster the clock speed the faster the instructions are processed

Question 18

What’s a dual-core

Answer 18

Has two processors in the same integrated circuit, linked together

Question 19

What do dual-core processors have the potential to do

Answer 19

Perform twice as many instructions, however it doesn’t always perform to the rate as software may not be able to take advantage of both cores

Question 20

What is cache memory

Answer 20

A small amount of very fast, expensive memory in the CPU

Question 21

How does cache effect speed

Answer 21

RAM is a relativley slow memory to access and it’s further away from the processor that cache

Question 22

What is cache used for

Answer 22

Program instructions and data that are fetched are stored in cache in case they are needed again soon

Question 23

What are the benefits of cache

Answer 23

The data used most often by the CPU is available extremely quickly

Question 24

What are embedded systems

Answer 24

A single microprocessor that includes RAM. ROM and a CPU.

Question 25

What are the 2 types of primary storage

Answer 25

-RAM (Random access memory)
-ROM (Read only memory)

Question 26

What can RAM do

Answer 26

Can be read from and written to

Question 27

What does the RAM usually store

Answer 27

-The operating system (or part currently in use)
-The software currently in use
-The data which the software is using

Question 28

What does volatile mean

Answer 28

It loses the data if the power is off

Question 29

Is RAM volatile or non-volatile

Answer 29

Volatile

Question 30

What’s usually put on RAM first

Answer 30

The operating system

Question 31

What happens if you run out of space on RAM

Answer 31

Virtual memory in the hard disk is used as an extension

Question 32

What are the advantages of virtual memory

Answer 32

-Uses cheap secondary storage on the hard drive
-Prevents error messages saying ‘out of memory’ – the programs and files will still open

Question 33

What are the disadvantages of virtual memory

Answer 33

-Accessing virtual memory is very slow
-To access data, the existing data in RAM needs to be copied to the virtual memory, then data in virtual memory needs to be copied to RAM

Question 34

What can be done on ROM

Answer 34

Can be read from but not written to

Question 35

Is ROM volatile or non-volatile

Answer 35

Non-volatile

Question 36

What does ROM store

Answer 36

-The initial program that is run when the computer is turned on (bootstrap)
-The basic input/output system (BIOS)

Question 37

What does the bootstrap do

Answer 37

It tells the computer where it will find the operating system on the hard drive

Question 38

What does the BIOS do

Answer 38

It controls basic technical configuration of the computer such as the processor speed and system time