HIPPI

HIPPI ("HIgh Performance Parallel Interface") is a computer bus for the attachment of high speed storage devices to supercomputers. It was popular in the late 1980s and into the mid-to-late 1990s, but has since been replaced by ever-faster standard interfaces like SCSI and Fibre Channel.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), but was soon upgraded to include a 1600 Mbit/s (200 MB/s) mode running on fibre optic cable. An effort to improve the speed resulted in HIPPI-6400, which was later re-named GSN (for "Gigabyte System Network") but saw little use due to competing standards. GSN had a full-duplex bandwidth of 6400 Mb/s or 800 MB/s in each direction.

To understand why HIPPI is no longer used, consider that Ultra3 SCSI offers rates of 160 MB/s, and is 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.