View source for HIPPI

{{Short description|Computer bus}}
{{Distinguish|Hippie}}
{{For|the upcoming Telugu film|Hippi (film)}}

[[File:SerialHIPPIfibre optic cable.jpg|thumb|right|Serial HIPPI fibre optic cable]]

'''HIPPI''', short for '''High Performance Parallel Interface''', is a [[computer bus]] for the attachment of high speed storage devices to [[supercomputer]]s, in a [[Point-to-point link#Point-to-point|point-to-point link]].<ref>{{cite web
 |title       = HIPPI FAQs
 |url         = http://www.hnf.org/faqs.htm
 |publisher   = High Performance Networking Forum
 |date        = 1999-02-26
 |access-date  = 2009-06-02
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20090916055443/http://www.hnf.org/faqs.htm
 |archive-date = 2009-09-16
}}</ref> It was popular in the late 1980s and into the mid-to-late 1990s, but has since been replaced by ever-faster standard interfaces like [[Fibre Channel]] and [[10 Gigabit Ethernet]].

HIPPI was the first “near-gigabit” (0.8&nbsp;Gbit/s) ([[American National Standards Institute|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 were integrated into such technologies as [[InfiniBand]].  What is remarkable about HIPPI is that it came out when [[Ethernet]] was still a 10&nbsp;Mbit/s data link and [[SONET]] at [[OC-3]] (155&nbsp;Mbit/s) was considered leading edge technology.

The first HIPPI standard (HIPPI-PH) defined a 50-pair (100-[[wire]]) unidirectional [[twisted pair]] cable, running at 800&nbsp;Mbit/s (100&nbsp;MB/s) with maximum range limited to {{convert|25|m}}. A bidirectional connection therefore required two separate cables. 32 bits are transferred in parallel with a 25 MHz clock.<ref>{{Cite web |url=https://hsi.web.cern.ch/hippi/spec/introduc.htm |title=Introduction to the Hippi Specifications |date=1994-09-14 |access-date=2023-11-10 |website=CERN |last=Van Praag |first=Arie}}</ref><ref name="hippiguard">{{Cite book |date=1999-10-19 |doi=10.1109/PI.1999.806412 |chapter=From HiPPI-800 to HiPPI-6400: A changing of the guard and gateway to the future |title=Proceedings. 6th International Conference on Parallel Interconnects (PI'99) (Formerly Known as MPPOI) |last1=Tolmie |first1=D. |last2=Boorman |first2=T.M. |last3=Dubois |first3=A. |last4=Dubois |first4=D. |last5=Feng |first5=W. |last6=Philp |first6=I. |pages=194–201 |isbn=0-7695-0440-X |s2cid=57080285 }}</ref> Later standards included a 1600&nbsp;Mbit/s (200&nbsp;MB/s) mode (using two cables running at the same 25 MHz clock in parallel) as well as Serial HIPPI using [[fibre optic]]s with a maximum range of {{convert|10|km}}.<ref>[https://whatis.techtarget.com/definition/HIPPI-High-Performance-Parallel-Interface Tech Target, HIPPI (High-Performance Parallel Interface), March 2011, by Rosario D'Elia, Mark Motsko, and Stephen C. Tenbrink ]</ref>

HIPPI usage dwindled in the late 1990s. This was partly because [[Ultra3 SCSI]] offered rates of 320&nbsp;MB/s and was available at almost any computer store at commodity prices.{{citation needed|date=November 2023}} Meanwhile, Fibre Channel offered simple interconnect with both HIPPI and SCSI (it can run both protocols) and speeds of up to 400&nbsp;MB/s on fibre and 100&nbsp;MB/s on a single pair of twisted pair copper wires.{{when|date=November 2023}} Both of these systems have since been supplanted by even higher performance systems during the 2000s.

<gallery>
Image:Paragon XP-E - MP64 top.jpg|[[Intel Paragon]] I/O node with HIPPI interface
Image:Paragon XP-E - MP64 side.jpg|Parallel HPPI interface connections
File:GSN_card_HIPPI-6400.jpg|GSN - HIPPI-6400 card
File:GSN_HIPPI-6400_cable.jpg|Serial GSN HIPPI-6400 fibre optic cable
</gallery>

==GSN - HIPPI-6400 ==
From 1996 on an effort to improve the speed resulted in HIPPI-6400,<ref>{{cite web
|title=HiPPI-6400/Gigabyte System Network
|url=http://public.lanl.gov/radiant/research/architecture/hippi.html
|publisher=[[Los Alamos National Laboratory]]
|year=2001
|access-date=2015-01-12
|archive-date=2016-03-04
|archive-url=https://web.archive.org/web/20160304195041/http://public.lanl.gov/radiant/research/architecture/hippi.html
|url-status=dead
}}</ref> which was later renamed to '''GSN''' (for '''Gigabyte System Network'''), but GSN saw little use due to competing standards and high cost. GSN has a full-duplex bandwidth of 6400&nbsp;Mbit/s or 800&nbsp;MB/s in each direction. GSN was developed by [[Silicon Graphics International|Silicon Graphics]] and [[Los Alamos National Laboratory]]. It uses a parallel interface for higher speeds.

GSN copper cables (HIPPI-6400-PH) are limited to {{convert|40|m}}.<ref>{{Cite web |url=http://cerncourier.com/cws/article/cern/28105 |title=CERN Courier, The Gigabyte System Network is demonstrated at CERN, Nov 2, 1999 |access-date=September 4, 2013 |archive-date=March 4, 2016 |archive-url=https://web.archive.org/web/20160304234338/http://cerncourier.com/cws/article/cern/28105 |url-status=dead }}</ref> Like HiPPI-800, GSN uses two separate simplex channels (one in each direction). Unlike HiPPI-800, they are combined in a single cable and connector. Each channel consists of 16 data lines, four control lines, one framing line and two clock lines, for a total of 23 lines, all of which are differential. The connectors (Berg Micropax 100<ref>{{Cite web |url=https://chep2000.pd.infn.it/pres/pre_d005.ppt |title=A SHORT Introduction to The GSN Specifications |date=1997-02-18 |access-date=2023-11-11 |last=Van Praag |first=Arie |publisher=CERN}}</ref>) have 100 pins total, of which 92 (23×2×2) are used.<ref>{{Cite web |url=https://www.osti.gov/servlets/purl/442483 |title=HIPPI-6400 Technology Dissemination |date=1996-11-13 |access-date=2023-11-10 |last=Hoffman |first=James R. |publisher=Los Alamos National Laboratory}}</ref><ref>{{Cite web |url=https://irix7.com/techpubs/007-3896-001.pdf |title=SGI GSN Hardware Owner's Guide |date= |access-date=2023-11-10 |publisher=SGI}}</ref>

Fiber-optic cables (HIPPI-6400-OPT) are limited to 1&nbsp;km. It uses the same principal signals as the copper interface, but runs everything at twice the clock rate, which halves the number of data and control fibers. Each channel thus consists of 8 data fibers, two control fibers and one clock and framing fiber each. All 12 fibers of a channel are bundled in a single multi-fiber connector and cable. A full-duplex connection thus consists of two separate cables.<ref name="hippiguard"/>

==See also==
{{div col|colwidth=30em}}
* [[GG45]]
* [[List of device bandwidths]]
* [[Optical communication]]
* [[Optical fiber cable]]
* [[Parallel optical interface]]
* [[TERA]]
* [[XAUI]]
{{div col end}}

==References==
{{Reflist}}

{{Computer-bus}}

[[Category:Computer buses]]
[[Category:Computer storage buses]]