1.2 Types of processors Flashcards
what is a RISC processor?
RISC is a reduced instruction set computer, and has an instruction set architecture has a set of attributes that allows it to have a lower cycles per instruction.
what is a CISC processor?
CISC is a Complex instruction set computer, where single instructions can execute several low-level operations or are capable of multi-step operations or addressing modes within single instructions.
features of CISC:
- Used in laptops and desktop computers
- Has more complex hardware
- Multiple machine cycles per instruction
- Physically larger in size and require more silicon thus more expensive
- Greater energy consumption
- More intensive tasks will do better with CISC
- Cant support pipe-lining
features of RISC:
- Used in smart phones and tablets
- Has simpler hardware
- Single machine cycle per instruction
- Smaller in size as less complex circuitry is required less silicon thus cheaper
- Lower energy requirements and can go into sleep mode
- Run at lower clock speed but can perform simpler tasks faster than CISC
- Can support pipe-lining
what is pipe-lining?
pipe-lining is starting the next step before finishing the first one by passing it into the next space. pipe-lining only works is the next instruction can be predicted.
If the wrong instruction is fetched the system “flushes the pipe”, and retrieves the correct instruction.
what is a serial system?
with a serial system the problem should be able to be split down into discrete pieces of work that can be solved simultaneously. the system should be able to execute multiple program instructions at any moment in time, and be solved in less time with multiple computer resources than with a single computer resource.
what is a parallel system?
With all parallel systems, the various processors in the CPU have to be able to communicate with each other to ensure that any changes to the data being processed is updated with the other processors.
There is an additional level of complexity as threads have to be combined in order to provide the solution to the original problem
The complexity of parallel systems made it be quicker just to execute the instruction on a single core however as programmers have been adapt to writing for parallel systems.
what are co-processors?
Co-processors are additional processors which are designed for very specific tasks to help the CPU.
The co-processor and the central processor operate on different tasks at the same time which has the effect of speeding up the overall execution of the program. This is the reasons why computers with graphics cards run video games better.
examples of co-processors?
Common examples of co processors are:
- FPU: floating point unit.
- DSP: digital signal processor. (sound card)
- GPU: graphics processing unit.
what is a Single instruction, multiple data (SIMD) system?
Single instruction: all processing units execute the same instruction at any given clock cycle.
Multiple data: each processing unit can operate on a different data element.
-Best suited for specialized problems characterized by a high degree of regularity, such as graphics/image processing.
what is a Multiple instruction, single data (MISD) system?
Multiple instruction: each processing unit operates on the data independently via separate instruction streams.
Single data: a single data stream is fed into multiple processing units.
what is a Multiple instructions multiple data (MIMD) system?
Multiple instruction: every processor may be executing a different instruction stream
Multiple data: every processor may be working with a different data stream.
-currently, the most common type of parallel computer-most modern supercomputers fall into this category.
