Dynamic Interconnection Techniques for Parallel Communication*

Parallel computing has contributed significantly to Defence applications. This field has helped in the development of dedicated hardware/software for ballistic missile defence system. In parallel computers, interprocessor communication mechanism strongly influences overall performance of the system. If a parallel computer is composed of n processors and each processor has a performance p, then the maximum potential of the system is np. The present review concentrates on interprocessor communication. Crossbar and delta network is discussed in detail. Cogent XTM-a better solution over crossbar network is also discussed. The MIMD approach breaks large processing task into sub-tasks and assigns search sub-task to different processors. An intrinsic MIMD computer is tightly coupled if physical connections are established via memory sharing and microprocessors communicate through a shared main memory. Otherwise, in loosely coupled systems, links and logical communication can be assimilated to packet switching. Each processor has a set of 1/0 devices and a large local memory where the processor accesses most of its instruction and data. 2. INTERCONNECTION NETWORK Interconnection network basically refers to communication between processors a~d the memory modules and between the processors and the 110 systems. The parallel computers can be classified on the internal structure of the interconnected network. The single shared bus is widely used in parallel systems. Here it is extremely difficult to eliminate bus contention. It can be avoided to some extent by forming the multiple bus network where each processor or memory unit or 110 device is connected to one or more of available buses. The crossbar interconnection network is a multiple bus system, where all units like I