Pengolahan Paralel

Shared Memory & Interconnection Network

• In most interesting problems that we wish to solve on a SIMD computer, it is desirable for the processors to be able to communicate among themselves during the computation in order to exchange data or intermediate results.

This can be achieved in two ways,
SIMD computers

• where communication is through a shared memory, and 
• Where it is done via aninterconnection network. 

Parallel Random Access Machine

• Extend the traditional RAM (Random Access Memory) machine 

• Interconnection network between global memory and processors 
• Multiple processors 

Characteristics

• Processors Pi (i (0 ≤i ≤p-1 )

1. each with a local memory
2. i is a unique identity for processor Pi

• A global shared memory

1.  it can be accessed by all processors

Types of operations:

• Synchronous

1. Processors work in locked step

at each step, a processor is active or idle
suited for SIMD and MIMD architectures

• Asynchronous

1. processors have local clocks 
2. needs to synchronize the processors

 suited for MIMD architecture

• Example of synchronous operation