A multiprocessor system on a chip (MPSoC) implements parallel processing and include a plurality of cores with inter-core communication. This communication is implemented by an on-chip switch fabric in communication with each core, or by shared memory in communication with each core. In another embodiment, a parallel processing system is implemented as a Howard Cascade and uses shared memory for implementing inter-chip communication. The parallel processing system includes a plurality of chips, each formed as an MPSoC, and implements communication between the chips using shared memory.