Building the 4 processor SB-PRAM prototype

The SB-PRAM is a massively-parallel, uniform memory access (UMA) shared-memory computer. The main ideas of the design are multithreading on the instruction level, hashing of the address space, and combining in the butterfly network. We have built a first research prototype with four physical processors, and thus 128 virtual processors, to demonstrate the feasibility of the concept. The programming environment consists of a FORK compiler for specifying PRAM programs, an extended C compiler and the P4 library. The machine runs a parallel operating system which provides program execution and I/O system calls. The SB-PRAM allows for efficient programs with predictable performance. Some examples are presented. The four-processor prototype is the first step towards a 128-processor machine for which we are adapting the existing hardware