1.1.2 Types of Processor

Question 1

What are the key facts about CISC?

Answer 1

Complex Instruction Set Computing

• Each Instruction may take multiple clock cycles
• Instructions are different sizes (bits)
• Complicated processor design - circuitry is expensive
• More instructions than RISC (larger instruction set)
• Some instructions in CISC will rarely get used

Question 2

What are the key facts about RISC?

Answer 2

Reduced Instruction Set Computing / Computer

• Each Instruction will take one clock cycle
• Instructions are the same size (bits)
• Simple processor design (Less transistors), so cheaper to produce
• Less instructions than CISC
• Most Instructions are used regularly (due to limited range)
• Produces less heat and uses less power than CISC

Question 3

What are the key facts about a GPU?

Answer 3

GPU - Graphics Processing Unit

Is a co-processor specialised in rendering graphics

Specialist instructions available

1000s of cores that can apply the same instruction to multiple pieces of data simultaneously

Question 4

What is parallel processing?

Answer 4

Will allow multiple separate jobs to run concurrently.

Can be achieved through multiple processors or distributed across multiple cores in a single CPU or GPU.

Question 5

What is a multicore system?

Answer 5

More than one processing unit in a single processor

Each core can independently process instructions at the same time.

Question 6

What are some limitations of parallel processing?

Answer 6

Writing algorithms for parallel processing is more challenging.

Some tasks cannot be done in parallel due to relying on each others output