The BBN TC2000 is a shared memory MIMD based on the Motorola 88100 RISC processor [19]. It is build on top of a Butterfly switch board and it has a distributed shared memory, that is, memory is distributed across boards but a global address space is granted to all the processors. It should be clear that non-local accesses are much more expensive than local accesses. The machine used for the time measurements has 128 processors and 2 GB of RAM.
The operating system is the Uniform System (based on Mach) and it gives the user the ability to allocate memory and processors in several different ways. For process management control, the system supports some fork equivalent calls, that generates only one process per processor with no task switching. The user may further specify some parameters, usually ranges of operation. This implementation uses the one parameter function call(GenOnI), and the two parameter function call (GenOnA). Several locking mechanisms are available for synchronization.