Hardware

Question 1

central processing unit (cpu)

Answer 1

processes instructions and data that are input into the computer so that the result can be
output

Question 2

control unit (CU)

Answer 2

manages other components of the cpu and overall operation (including fetch-decode-execute cycle and ALU)

Question 3

arithmetic logic unit (alu)

Answer 3

responsible for carrying ou mathematical operation (eh bit shifts)

Question 4

why dos alu use accumulator (acc)

Answer 4

temporarily store the data while performing calculations

Question 5

registers

Answer 5

small areas of storage found within cpu (PC, MAR, MDR, CIR, ACC)

Question 6

pc

Answer 6

program counter - holds the address of the next instruction to be fetched

Question 7

mar

Answer 7

memory address register - used when reading or writing data from/to ram

Question 8

mdr

Answer 8

memory data register - used to read/write from/to ram. mdr contains data while mar contains address

Question 9

cir

Answer 9

current instruction register - holds the instruction which is currently being decoded or executed

Question 10

acc

Answer 10

accumulator - used to hold data being worked on by alu

Question 11

bus

Answer 11

way of communicating between components

Question 12

how many buses does cpu have

Answer 12

3 (control, address, data)

Question 13

control bus

Answer 13

carries control signals from the control unit to other components of the cpu

Question 14

address bus

Answer 14

carries addresses from mar to ram to indicate which address will b selected

Question 15

address bus is

Answer 15

unidrectional

Question 16

data bus

Answer 16

carries thee data to be written from the mdr to ram

Question 17

the data bus is

Answer 17

bidirctional

Question 18

fetch-decode-execute cycle

Answer 18

cycle computer follows to run programs

Question 19

active computer programs are stored in the

Answer 19

ram

Question 20

fetch steps

Answer 20

• PC contains the location of the next instruction
• This address is copied to the MAR.
• pc is incremented by 1 so that it points to next instruction
• address bus carries value in mar to ram
• control bus sends read signal to ram
• contents of mdr are copied to cir

Question 21

decode steps

Answer 21

cu decodes instruction in cir

Question 22

execute steps

Answer 22

• instruction is sent to alu to be executed
• alu may use acc to temporarily store its results

Question 23

factors that affect cpu performance

Answer 23

clock speed, cores, cache

Question 24

clock speed

Answer 24

• determines number the cycles cpu can perform each second (measured in gigahertz)
• higher clock speed -> more heat -> more energy

Question 25

core

Answer 25

processor within cpu that carries out one instruction at a time

Question 26

why is a multi core cpu not necessarily an advantage

Answer 26

they run tasks simultaneously however, individual programs have instruction that run in a sequence

Question 27

cache

Answer 27

fast memory located within cpu used to store temporary copies of data in most commonly accessed ram locations

Question 28

read operation

Answer 28

To read, the registers MAR and MDR are needed

The address is copied to the MAR

Signal is sent from the processor to the memory

Content is copied to the MDR

Question 29

write operation

Answer 29

Data is written on the MDR

The address is written in the MAR

A ‘write’ signal is sent from the processor to the memory unit through the CU

Question 30

what is a microprocessor?

Answer 30

type of integrated circuit
on a single chip

Question 31

structure of computer that has a
Von Neumann architecture

Answer 31

• units: arithmetic logic unit (ALU) and control unit (CU)
  – registers: program counter (PC), memory address register (MAR), memory data register (MDR), current instruction register (CIR) and accumulator (ACC)
  – buses: address bus, data bus and control bus

Question 32

dual core

Answer 32

can work on two instructions t a time (higher CPU speed)

Question 33

instruction set

Answer 33

list of all the commands
that can be processed by a CPU and the
commands are machine code

Question 34

add instruction set

Answer 34

add two numbers together

Question 35

sub instruction set

Answer 35

subtract one number from another

Question 36

inp instruction set

Answer 36

input data from an input device

Question 37

out instruction set

Answer 37

output data from an outrput data

Question 38

load instruction set

Answer 38

load data from RAM

Question 39

store instruction set

Answer 39

save data to RAM

Question 40

what is an embedded system

Answer 40

• embedded system is used to perform a dedicated function (e.g. domestic appliances, cars, security systems, lighting systems or vending machines)
• This is different to a general purpose computer that is used to perform many different functions, (e.g. a personal computer (PC)
  or a laptop)