HIPPI (High Performance Parallel Interface) is a computer bus for the attachment of high speed storage devices to supercomputers, in a point-to-point link.  It was popular in the late 1980s and into the mid-to-late 1990s, but has since been replaced by ever-faster standard interfaces like SCSI and Fibre Channel.
The first HIPPI standard defined a 50-wire twisted pair cable, running at 800 Mbit/s (100 MB/s) with maximum range limited to 25 meters, but was soon upgraded to include a 1600 Mbit/s (200 MB/s) mode running on Serial HIPPI fibre optic cable with a maximum range of 10 kilometers.
In 1999 in an effort to improve the speed resulted in HIPPI-6400, which was later renamed GSN (for Gigabyte System Network) but this saw little use due to competing standards. GSN had a full-duplex bandwidth of 6400 Mbit/s or 800 MB/s in each direction. GSN was developed at Los Alamos National Laboratory and used parallel interface for higher speeds. GSN copper was limited to 50 meters and fibre optic to 1km.
To understand why HIPPI is no longer used, consider that Ultra3 SCSI offers rates of 320 MB/s, and was available at almost any corner computer store. Meanwhile, Fibre Channel offered simple interconnect with both HIPPI and SCSI (it can run both protocols) and speeds of up to 400 MB/s on fibre and 100 MB/s on a single pair of twisted pair copper wires.
HIPPI was the first “near-gigabit” (0.8 Gbit/s) (ANSI) standard for network data transmission. It was specifically designed for supercomputers and was never intended for mass market networks such as Ethernet. Many of the features developed for HIPPI are being integrated into such technologies as InfiniBand. What was remarkable about HIPPI is that it came out when Ethernet was still a 10 Mbit/s data link and SONET at OC-3 (155 Mbit/s) was considered leading edge technology.
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- Tech Target, HIPPI (High-Performance Parallel Interface), March 2011, by Rosario D'Elia, Mark Motsko, and Stephen C. Tenbrink
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- CERN Courier, The Gigabyte System Network is demonstrated at CERN, Nov 2, 1999