SCI technology is based on the ANSI/IEEE SCI standard 1596-1992 and is
designed to provide low latency and high bandwidth interfaces for
workstation clustering. In particular, this technology can provide latency and, consequently, can efficiently support both shared
memory and message passing applications between a variety of
workstation types. Bandwidth on individual links is one
gigabit-per-second, and the standard can support either ring or
switched communications topologies. The SCI standard can be used to
create a virtual bus, so that workstation internal bus protocols can
be extended between (heterogeneous) clusters of computers.
I found only one company offering SCI products at SuperComputing '94 - Dolphin Interconnect Solutions, a company with main offices located in Norway. Dolphin offers SCI interface cards to interconnect SBus-based or VME-bus-based workstations. In additional, this company offers bridging solutions between:
No pricing information was available for this networking technology, however, interconnections are made with relatively low cost shielded twisted pair cables. At these bandwidths, this physical interconnection media surely limits the distances between clustered workstations. Dolphin is examining using ATM-based communications to extend the distances between clustered workstations. If computers are clustered in a ring topology, latency could suffer as a function of the distance (number of network hops) from transmitter to receiver, which is a function of their relative locations on the ring. The SCI protocol can be used in a switched architecture, however, no information on switch availability or pricing was available. In general, this is a limited use networking technology, only to be used in high-performance workstation clusters.