Multi-Processor Organization

Write a short note on types of Parallel Processor.

What is Parallel Processing?
  • It is a way of information processing that uses more than one computer processor simultaneously to perform work on a problem.
  • Earlier the systems were designed in a way that only one process could occur at one time which used to consume a plenty of time as only the completion of one process could mark the beginning of another. In order to cope with this and to make the execution faster, the concept of “parallel processing” was introduced.
  • Parallel processing is the processing of program instructions by dividing them among multiple processors with the objective of running a program in less time.
Parallel processing
  • Is carrying out the processes parallel.
  • Makes a program run faster.
  • Saves the execution time.
Types of Parallel Processor

Types of parallel
The major classification of parallel processors is on the basis of the no. of processes that can be processed simultaneously. The types are:

1. Single Instruction stream Single Data stream (SISD)
  • Synonyms to the sequential systems.
  • Executes only one process at one time.
  • Found in the single CPU systems.
2. Single Instruction stream Multiple Data streams (SIMD)
  • Single processing unit signifies that all instructions will be taken by one processor.
  • Multiple data streams signifies that the execution units are different.
3. Multiple Instruction stream Single Data stream (MISD)
  • Follows the concept of “pipelining”.
  • Single data stream is made to pass through the pipeline.
  • The multiple executers available in the pipeline executes the instructions.
4. Multiple Instruction stream Multiple Data stream (MIMD)
  • Works with systems having many CPUs.
  • Multiple instructions are carried out at one time.