ON THE PHYSICAL DESIGN OF PRAMS

The Saarbrucken Parallel Random Access Machine (SB-PRAM) is a scalable shared memory machine. At the gate level it is a re-engineered version of the Fluent machine [A. G. Ranade, S. N. Bhatt and S. L. Johnson. The Fluent Abstract Machine. In Proc. 5th MIT Conference on Advanced Research in VLSI, pp. 71-93 (1988)]. It uses hashing of addresses. combining and latency hiding. A prototype with 128 processors is presently being designed. In this paper we deal with several problems related to the physical design of this machine such as the total number of network chips, the geometrical arrangement of boards in the network and the VLSI realization of certain sorting arrays. We also present an extremely fast method to rehash addresses without use of external memory.