|StarT Voyager is a parallel system designed to support both message passing and coherent dis
tributed shared memory. StarT Voyager is constructed from a collection of commercial SMPs
connected by a fast network which interfaces to each SMP's coherent memory bus via a Network
Endpoint Subsystem (NES) card. Each SMP, referred to as a site, is a desktop class, commercial, dual PowerPC 604 SMP It uses a stock PC/workstation class motherboard which can accommodate two processor cards. Each processor card normally contains one 604 processor and an in-line
L 2 cache. For StarT Voyager, we replace one of the two processor cards in each SMP site with
an NES card, making each site into a uniprocessor system. This 604 processor, referred to as the
application processor or aP, runs a copy of AIX augmented with a parallel layer to coordinate
parallel job execution.