Parallel Systems

Shared and distributed memory.

•  All processors have access to a pool of shared memory.
• Access time vary from CPU to CPU in NUMA systems.
• Example: SGI Altix, IBM P5 nodes.

• Memory is local to each processor.
• Data exchange by message passing over a network.
• Example: Clusters with single-socket blades.   

Hybrid system.

• A limited, N ,number of processors have access to a common pool of shared memory.
• To use more than N processors requires data exchange over a network.
• Example: Cluster with multi-socket blades.