The Free On-line Dictionary of Computing (30 December 2018):

Scalable Coherent Interface

    (SCI) The ANSI/IEEE 1596-1992
   standard that defines a point-to-point interface and a set
   of packet protocols.  The SCI protocols use packets with a
   16-byte header and 16, 64, or 256 data bytes.  Each packet
   is protected by a 16-bit CRC code.

   The standard defines 1 Gbit/second serial fiber-optic
   links and 1 Gbyte/second parallel copper links.  SCI has two
   unidirectional links that operate concurrently.

   The SCI protocols support shared memory by encapsulating
   bus requests and responses into SCI request and response
   packets.  Packet-based handshake protocols guarantee
   reliable data delivery.  A set of cache coherence protocols
   are defined to maintain cache coherence in a shared memory
   system.

   Message passing is supported by a compatible subset of the
   SCI protocols.  This protocol subset does not invoke SCI cache
   coherency protocols.

   SCI uses 64-bit addressing and the most significant 16 bits
   are used for addressing up to 64K nodes.

   http://uni-paderborn.de/pc2/systems/sci/.

   [Applications?]

   (1999-03-22)