Central Processing Unit 1.1

Question 1

Purpose of cpu

Answer 1

• process data

- where all sorting, searching, calculating and decision-making takes place

Question 2

F-D-E Cycle in simple terms

Answer 2

• fetches instructions from ram (from program)
• decodes those instructions
• executes order

Question 3

What computer hardware does the cpu controlp

Answer 3

• input/output devices
• dvd drive
• sound system
• graphic system

Question 4

Main components of the cpu

Answer 4

• controls unit
• arithmetic login unit
• registers
• cache
• clock
• date buses (3types)

Question 5

Name the three types of data buses

Answer 5

• address bus
• data bus
• controls bus

Question 6

Control unit - state 3 points

Answer 6

• monitors the flow of data between cpu/hardware = making sure the correct fast goes to the right hardware
• manages the input/output signals
• uses clock signal to synchronise the fde cycle

Question 7

Arithmetic logic unit (ALU) - 3 points

Answer 7

• handles data processing inside the CPU
• perform standard arithmetic operations (+-)
• performs comparisons and deals with logic (I.e is this value greater than that value)

Question 8

Registers - 3 points

Answer 8

• type of memory located inside the cpu
• speeds processing up
• there are many registers in the cpu
• holds next instruction needed to be executed
• holds calculations/results and current instruction being decoded

Question 9

Why do registers speed up retrieving data

Answer 9

-it is faster to shift data to/from the registers than getting it from ram all the time

Question 10

Cache - 5 points

Answer 10

• aka immediate access store = fast type of ram
• faster to access by cpu than the ram
• slower to access by the cpu than the registers
• can have internal cache + external cache (outside the cpu)
• holds instructions that is frequently used/ will be used

Question 11

Clock

Answer 11

• tiny quartz crystal
• ticks at a very fast , steady pace
• during each tick the cpu completes one fde Cycle
• average speed = 3GHz = 3,000 million orders per second the cpu does

Question 12

What happens as data is moved closer to the cpu

Answer 12

Speed increases but less memory capacity

Question 13

What happens at dat is moved out of the cpu

Answer 13

Memory capacity increases

But is slower

Question 14

The buses

Answer 14

A set of wire /tracks laid Ona printed circuit board

-role is to carry data around the system

Question 15

Data bus

Answer 15

Carries data around the system

Question 16

Address bus

Answer 16

Carries information around the system
To the location of the data
-requests the location of data from ram

Question 17

Control bus

Answer 17

Handles commands to control devices

E.g monitor

Question 18

Fetch - decode - execute cycle

Answer 18

-the 3 steps followed by the cpu in order to process data

Question 19

The fetch stage of the f-d-e cycle

Answer 19

• all programs are loaded in ram so that the cpu can have access to them
• cpu requests an address of data through an address bus
• data bus then carries this data from the ram to the cpu
• then stores them in its own registers

Question 20

Decode stage of f-d-e cycle

Answer 20

-cpu works out instruction

Question 21

Execute stage of f-d-e cycle

Answer 21

• data processing happens

- instructions are carried out on data

Question 22

Journey of data

Answer 22

• input device sends data to the cpu = received by the control unit
• controls unit sends this data to the ram to be sued later
• then data will be transferred from ram to cache
• then sent to alu to be processed
• controls unit will send the processed data back to the output device