Symmetric Multi Processing [SMP]

Symmetric Multi-Processing [SMP] is a computer architecture that provides fast performance by using multiple CPUs to run individual processes simultaneously (multiprocessing).

Unlike asymmetrical processing [in which separate specialized processors are used for specific tasks], any idle processor can be assigned any task. Additional CPUs can be easily added to improve performance and handle increased loads. SMP is utilized by both:

• OS- Both UNIX and Windows NT operating systems support SMP.
• Applications - Specific applications can benefit from SMP if the code allows multithreading.

SMP uses a single operating system and shares common memory and disk input/output resources. This is distinct from more advanced 'Shared Nothing' architectures, where each processing node runs totally independently.

SMP is similar to Massively Parallel Processing [MPP], the main difference being that in SMP systems all the CPUs share the same memory, whereas in MPP systems, each CPU has its own memory.

MPP systems are more difficult to program because the application must be divided in such a way that all the executing segments can communicate with each other.

However, MPP does not suffer from the bottleneck problems inherent in SMP systems, which occurs when all the CPUs attempt to access the same memory at once.

Next: Massively Parallel Processing

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