Nonuniform Memory Access (NUMA)

Figure 4: NUMA shared memory system.

• In the NUMA system, each processor has part of the shared memory attached (see Fig. 4).
• The memory has a single address space. Therefore, any processor could access any memory location directly using its real address. However, the access time to modules depends on the distance to the processor. This results in a nonuniform memory access time.
• A number of architectures are used to interconnect processors to memory modules in a NUMA. Among these are the tree and the hierarchical bus networks.
• Examples of NUMA architecture are BBN TC-2000, SGI Origin 3000, and Cray T3E.