1.1.2 types of processors Flashcards
Define CISC and how does it work
Complex instruction set computing (CISC) when this is used manufactures when making chips for this make a much larger instruction set on the CPU when the complier sees a multiple command in a high level language such as C sharp it can turn this into a single machine code instruction as it is available in the instruction set assuming there is a multiply in the instruction set this one instruction but this would take multiple machine cycles to complete. Most laptop and desktop computers run on Complex instruction set computing architecture and this is commonly made by groups such as Intel.
Define RISC and how does it work
Reduced instruction set computing (RISC) now there is less complex instruction set less complex hardware is required but now there is a dramatically reduced instruction set more complex software is required and the complier will have to generate more lines of low level machine code such as the code below that would be used in multiplying two numbers this is a quad command which is a low level machine code for multiply this multiplies the in register one and register two and stores it in the memory this is an increase from one instruction to 4 however the upside is each command can be executed in one machine cycle. A benefit for using this reduced instruction set it allows for a system called pipelining to be used and this is used in speeding up processing with pipelining this allows for the first two instructions to be executed at once as they don’t depend on each other but this can only be done in a reduced instruction set computing architecture most smartphones and tablets used RISC architecture.
Define GPU and how does it work
In the modern computer as they became more powerful code processors where added these are any additional processor added to increase the performance and speed of the computer and they are used in specialised tasks they execute concurrently to the main CPU but with a highly bespoke set of electronics the most commonly known code processor is the Graphic Processing Unit (GPU) these where initially used in rendering graphics now the large number of cores in the GPU are being exploited so that they can process many parallel streams of data no matter the type of the data even though the GPU has 100’s or 1000’s of stream processors they each run slower than a normal CPU core and have fewer features therefore GPU’s are not faster however are highly specialised.
What is the difference between CISC and RISC
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Over than graphical uses what else can a GPU be used for?
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What are CISC processors used in?
Used in laptops and desktop computers made by intel and AMD
Use multiple machine cycles per instructions
Greater energy and space consumption
More intensive tasks work more efficiently on RISC
What are RISC processors used in?
Used in smartphones and tablets based around ARM processor
Simpler hardware and uses single machine cycle per instruction
Run on lower clock speed can support pipelining
What is a Multicore system
A multicore processor is a single chip which contains two or more independent processing units these are refereed as cores each core can execute ordinary CPU commands inside a single core such as add and store commands commonly these cores are integrated onto a single physical chip this is known as a Chip Multi processor (CMP) this is still commonly still referred to the as the CPU. There are multiple types of multicore processor a dual core as shown below four cores which is called a quad core processor then six cores a hex core then eight core which is Oct core or more. They can also be enhanced such as by sharing a memory cache and inter core connections to the cache. Doubling the cores doesn’t automatically double the processing power. Improvements in performance are mainly affected by the individual software program being run typically the gains in performance will be limited to the parts of the software program that have been designed to run in parallel over the multiple cores this problem is known as Amdahl’s law.
What is a Parallel system
Parallel processing is the process of instructions by dividing them amongst multiple processors or processor cores with the objective of running the overall program in less time in the earliest programs in this example the fetch decode execute cycle has been spilt between three processors and this speeds up computation due to the fact the next instruction can be fetched before the previous instruction has left the overall processor.
How are multiple processors used in the fetch decode execute cycle
If there are many processors this allows for increased processing power therefore individual cores can be used for the individual steps such as single processor dedicated to each fetch decode and execute
