Internal computer architrcture

Question 1

what is the CPU

Answer 1

CENTRAL PROCESSING UNIT

Question 2

What is the RAM

Answer 2

Random access memory

Question 3

what is the ALU and what does it do

Answer 3

• the arithmetic logic unit does arithmetic and logic

Question 4

what is the CU and what does it do

Answer 4

• Coordinates all activities of the CPU
• Directs flow of data between the CPU and other devices
• Accepts, decodes and handles execution of instructions
• sends memory reads and writes to main memory
• makes use of the status register and clock

Question 5

examples of registers within the CPU

Answer 5

• IR
• CIR
• ACC
• MDR
• PC

Question 6

what are registers

Answer 6

memory locations within the processor which work at very high speeds, and they are used to control the fetch decode execute cycle

Question 7

summarise the PC

Answer 7

• program counter
• stores the address of the next instruction

Question 8

summarise the MAR

Answer 8

• memory address register
• stores the address of the data or the instructions that are to be fetched from or sent to the memory

Question 9

summarise the MDR

Answer 9

• memory data register
• temporarily stores the data that is to be sent to or fetched from the memory

Question 10

summarise the CIR

Answer 10

• current instruction register
• stores the actual instruction being decoded and executed

Question 11

what does the ACC do

Answer 11

the accumulator stores the result of calculations

Question 12

summarise address bus

Answer 12

carries the address of the instruction or data in the MAR from the processor to the memory, unidirectional

Question 13

summarise data bus

Answer 13

the data bus carries data between the processor and the memory, bidirectional

Question 14

summarise the control bus

Answer 14

controls signals between the processor and the components, bidirectional

Question 15

What does the status register do

Answer 15

• Contains information about the state of the processor

Question 16

What does the clock do?

Answer 16

• It is the electronic unit that synchronises related components by generating regular pulses
• Measured in hertz
• The higher the clock rate, the faster, the computer may work

Question 17

Summarise, general-purpose registers

Answer 17

• temporarily holds data and instructions that are being processed by the cpu

Question 18

What is the program counter responsible for?

Answer 18

It holds the address of the next instruction to be executed

Question 19

What is the memory buffer register responsible for?

Answer 19

It’s used to temporarily stored the data which is read from a written to memory

Question 20

how does clock speed affect processor performance

Answer 20

• the CPU is regulated with clock signals
• the faster these cycles are, the more instructions can be executed per second

Question 21

how does cache size affect processor performance

Answer 21

cache memory provides faster data access to the CPU
- improves CPU efficiency by reducing the need to fetch data from slower main memory

Question 22

what is cache

Answer 22

small amount of expensive , fast memory inside/near to the CPU

Question 23

what are the levels of cache

Answer 23

L1 - embedded in the CPU chip, is the smallest and fastest
L2 - fairly fast and medium size (256kb - 2mb)

Question 24

what is a core

Answer 24

a complete copy of a CPU

Question 25

how does the number of cores affect the performance of the processor

Answer 25

• multiple cores allow a CPU to perform parallel processing, where different tasks can be accessed simultaneously

Question 26

what is the purpose of the CPU

Answer 26

to fetch, decode and execute instructions

Question 27

what does fetch do

Answer 27

causes the next instruction to be fetched from main memory

Question 28

what is a bus

Answer 28

a set of parallel wires connecting two or more components of a computer

Question 29

purpose of the control bus

Answer 29

to transmit command, timing and specific status information between system components

Question 30

what is a word

Answer 30

a fixed size group of digits which is handled as a unit by the processor

Question 31

what is an I/O controller

Answer 31

a device which interfaces between an input or output device and the processor

Question 32

what is the controller and what does it consist of

Answer 32

• an interface that allows connection of the controller to the system
• a set of data, command and status registers
• an interface that enables connection of the controller to the cable connecting the device to the computer

Question 33

what is an interface

Answer 33

a standardised form of connection defining things like signals

Question 34

examples of control signals

Answer 34

memory writes, reads, interrupt requests, clock, bus requests and grants

Question 35

what does the data bus transfer

Answer 35

data and instructions

Question 36

how does word length affect CPU performance

Answer 36

word length defines the amount of data a CPU can process at one time
- larger word lengths allow for processing larger chunks of data in a single cycle

Question 37

how does bus width affect CPU performance

Answer 37

address bus - the max memory address that can be transmitted is 2^n - 1 , higher width = more memory location accessed

data bus - width of data bus tells us how many bits can be transferred simultaneously , larger width means more bits of data can be moved simultaneously