Topic 1 - CPU Architecture

Question 1

Hardware

Answer 1

hardware is the physical stuff that makes up the computer system ( e.g motherboard, monitor)

Question 2

Software

Answer 2

software is the programs or applications that a computer system runs

Question 3

What is an embedded system

Answer 3

-embedded systems are computers built into other devices that performs specific function
- they often control and monitor machinery in dishwashers, microwaves, TVs, etc.

Question 4

Advantages of using embedded system

Answer 4

• easier to design
• cheaper to produce
• more efficient at doing their task

Question 5

What does the CPU do?

Answer 5

• it processes all of the data and instructions that make the system work
• it controls the rest of the computer system

Question 6

Control Unit

Answer 6

• it follows the FDE cycle
• it controls the execution of instructions in the right order
• it decodes instructions

Question 7

register

Answer 7

very fast memory location within the CPU that hold tiny bits of data needed by CPU

Question 8

ALU

Answer 8

• does arithmetic operations ( + , - , / , * )
• performs logical operations (AND, OR , NOT)
• contains accumulator register

Question 9

Cache

Answer 9

• very fast memory inside the CPU that stores regularly used data so the CPU can access it quickly
• can access it much quicker rather than accessing it from RAM
  -low capacity + expensive

Question 10

PC

Answer 10

• Program Counter
• points to the address of the next instruction

Question 11

MAR

Answer 11

• Memory Address Register
• holds the address of the instruction to be fetched or stored

Question 12

MDR

Answer 12

• Memory Data Register
• stores actual data or instruction that is fetched or stored from/ to memory

Question 13

Accumulator

Answer 13

• stores intermediate results of calculations in ALU

Question 14

FDE cycle ( FETCH )

Answer 14

• The address in the PC is copied to the MAR
• The address is sent to the RAM via the address bus
• The instruction stored in that address is copied to the MDR via the data bus

Question 15

FDE cycle ( DECODE )

Answer 15

• the contents of the MDR are copied into the CIR
• the contents of the PC are incremented so it points to the next address
• the contents of the CIR are divided into the opcode and operand
• CU interprets and decodes the opcode and prepares for next step

Question 16

FDE cycle ( EXECUTE )

Answer 16

• the instruction is performed
• this could be writing data to memory, doing a calculation or halting a program

Question 17

Which three factors affect CPU speed

Answer 17

• Clock speed
• Number of cores
• Cache Size

Question 18

Clock speed

Answer 18

• number of instructions a single core can carry out per second
• the higher the clock speed the more instructions that can be carried out per second,
• which means data is processed faster

Question 19

overclocking
- what are potential problems

Answer 19

manually increasing clock speed of computer’s CPU
- it can make CPU overheat or crash
- cooling system needed

Question 20

Cores

Answer 20

• each core processes data independently of the rest
• the more cores a CPU has the more instructions it can carry out at once
• it can process a batch of data faster

Question 21

when might increasing number of cores not affect anything?

Answer 21

• some software is not written to make us of multiple cores
• so it will not run quicker on a multi-core computer

Question 22

Cache size

Answer 22

• the CPU can access more regularly used data faster with a larger cache size
• it acts as a buffer between CPU and RAM
• because the CPU can access data faster from the cache than the RAM