Editing Sequent Computer Systems

{{Infobox company 
| name  = Sequent Computer Systems
| logo  = File:Sequent Computer Systems logo.svg
| type          = 
| caption        = 
| fate          = Acquired
| successor     = IBM
| foundation    = 1983
| defunct       = 1999
| location      = 
| industry      = High-end computer hardware
| key_people    = 
| products      = 
| num_employees = 
| parent        = 
| subsid        = 
| website       = {{web archive|url=https://web.archive.org/web/19980203152329/http://www.sequent.com/|title=sequent.com}}
}}
'''Sequent Computer Systems, Inc.''' was a computer company that designed and manufactured [[multiprocessing]] [[computer system]]s. They were among the pioneers in high-performance [[symmetric multiprocessing]] (SMP) [[Open system (computing)|open systems]], innovating in both hardware (e.g., [[cache (computing)|cache]] management and [[interrupt]] handling) and software (e.g., [[read-copy-update]]).

Through a partnership with [[Oracle Corporation]], Sequent became a dominant high-end [[Unix|UNIX]] platform in the late 1980s and early 1990s. Later they introduced a next-generation high-end platform for UNIX and [[Windows NT]] based on a [[non-uniform memory access]] architecture, NUMA-Q. As hardware prices fell in the late 1990s, and [[Intel]] shifted their server focus to the [[Itanium]] processor family, Sequent joined the [[Project Monterey]] effort in October 1998, which aimed to move a standard Unix to several new platforms.<ref name="CNET">[http://news.cnet.com/Sequent+was+overmatched,+CEO+says/2100-1001_3-228478.html Sequent was overmatched, CEO says], a July 1999 article from [[CNET Networks]]</ref>

In July 1999 Sequent agreed to be [[Data Sciences Ltd|acquired by IBM]].<ref name="nytimes">[https://query.nytimes.com/gst/fullpage.html?res=950DE2DB113CF930A25754C0A96F958260 Sequent Computer Systems To Be Acquired by I.B.M.], a July 13, 1999 article from ''[[The New York Times]]''</ref> At the time, Sequent's CEO said its technology would "find its way through IBM's entire product field"<ref name="CNET"/> and IBM announced it would "both sell Sequent machines, and fold Sequent's technology...into its own servers",<ref name="nytimes"/> but by May 2002 a decline in sales of the models acquired from Sequent, among other reasons, led to the retirement of Sequent-heritage products.<ref>[http://www.bizjournals.com/portland/stories/2002/05/20/daily45.html IBM lays off 250 in Beaverton], a May 2002 article from ''[[Portland Business Journal]]'', one of the [[American City Business Journals]]</ref>

Vestiges of Sequent's innovations live on in the form of data clustering software from [[PolyServe]] (subsequently acquired by HP),<ref>{{cite web
   |title=HP pays for PolyServe while IBM and Dell watch
   |website=[[The Register]]
 |url=https://www.theregister.co.uk/2007/02/27/hp_buys_polyserve
   |date=February 27, 2007}}</ref><ref>{{cite web
   |title=Hewlett-Packard to buy PolyServe
   |date=March 2007|url=https://www.infoworld.com/article/2635806/hewlett-packard-to-buy-polyserve.html}}</ref> various projects within [[OSDL]], IBM contributions to the [[Linux kernel]], and claims in the ''[[SCO Group, Inc. v. International Business Machines Corp.|SCO v. IBM]]'' lawsuit.<ref>{{cite web | title=SCO Falls Downstairs, Hitting its Head on Every Step — Updated: SCOsource is Born | website=Groklaw | date=17 May 2003 | url=http://www.groklaw.net/article.php?story=6 | access-date=27 September 2023}}</ref><ref>{{cite web | title=Oh, That is Why They Are Saying That | website=Groklaw | date=17 June 2003 | url=http://www.groklaw.net/article.php?story=59 | access-date=27 September 2023}}</ref><ref>{{cite web | title=And They Call Linus Careless | website=Groklaw | date=18 June 2003 | url=http://www.groklaw.net/article.php?story=66 | access-date=27 September 2023}}</ref><ref>{{cite web | title=Why Cringley Says SCO Will Lose | website=Groklaw | date=20 June 2003 | url=http://www.groklaw.net/article.php?story=72 | access-date=27 September 2023}}</ref><ref>{{cite news |author1=Aliza Earnshaw |title=PolyServe to join HP division |url=http://www.bizjournals.com/portland/stories/2007/02/26/daily23.html |access-date=27 September 2023 |work=Portland Business Journal |date=28 February 2007}}</ref>

==History==
[[File:SequentLogo.jpg|thumb|upright|Logo used from 1983 until the mid-1990s]]
Originally named '''Sequel''',<ref>[http://www.netlib.org/papers/advarch Advanced Architecture Computers] and [http://www.netlib.org/papers/advarch-post Part Two], Argonne National Labs, Technical Report No. 57, Jack J. Dongarra and Iain S. Duff</ref> Sequent was formed in 1983<ref name=RICM>{{Cite web|url=http://www.ricomputermuseum.org/Home/equipment/sequent-5000|title=Sequent Symmetry 5000}}</ref> when a group of seventeen engineers and executives left [[Intel]] after the failed [[Intel iAPX 432|iAPX 432]] "mainframe on a chip" project was cancelled; they were joined by one non-[[Intel]] employee. They started Sequent to develop a line of SMP computers,<ref>with some of their names included 
here [https://en.wikipedia.org/w/index.php?title=Sequent_Computer_Systems&diff=902882568&oldid=896743436]</ref> then considered one of the up-and-coming fields in computer design.<ref>{{Cite web|url=http://www.ultimate.com/phil/pdp10/10periphs|title=DEC 1077 and SMP}}</ref><ref>[http://www.bitsavers.org/pdf/dec/vax/8800/EK-8840H-UG-001_88xx_System_Hardware_Users_Guide_Mar88.pdf VAX 8820/8830/8840 System Hardware User's Guide]: by 1988 the VAX operating system was SMP</ref><ref>was up & coming @ 1077, already came by VMS</ref>

===Balance===
Sequent's first computer systems were the Balance 8000 (released in 1984) and Balance 21000 (released in 1986).<ref>{{Cite book 
   |author1=R. W. Hockney |author2=C. R. Jesshope 
   |title=Parallel Computers 2: Architecture, Programming and Algorithms 
   |publisher=Taylor & Francis |year=1988 |page=46 
   |isbn=0-85274-811-6}}</ref> Both models were based on 10&nbsp;MHz [[National Semiconductor]] [[NS32000|NS32032]] processors, each with a small write-through cache connected to a common memory to form a [[Shared memory architecture|shared memory]] system. The Balance 8000 supported up to 6 dual-processor boards for a total maximum of 12 processors.<ref>{{Cite web |url=http://homepages.inf.ed.ac.uk/cgi/rni/comp-arch.pl?Shmem%2Fsb.html%2CShmem%2Fsb-f.html%2CShmem%2Fmenu-seq.html |title=Archived copy |access-date=2022-07-17 |archive-date=2016-04-12 |archive-url=https://web.archive.org/web/20160412082437/http://homepages.inf.ed.ac.uk/cgi/rni/comp-arch.pl?Shmem%2Fsb.html%2CShmem%2Fsb-f.html%2CShmem%2Fmenu-seq.html |url-status=dead }}</ref><ref>{{Cite book | url=https://books.google.com/books?id=FJRVm8pDO9cC&q=balance+8000+sequent&pg=PT229 |title = Creative Destruction: Why Companies That Are Built to Last Underperform the Market--And How to Success fully Transform Them|isbn = 9780307779311|last1 = Foster|first1 = Richard|last2 = Kaplan|first2 = Sarah|date = 2011-04-20| publisher=Crown }}</ref><ref name="cs.berkeley.edu">[http://www.cs.berkeley.edu/~culler/machines/sequent.ps Machines. Sequent] cs.berkeley.edu</ref> The Balance 21000 supported up to 15 dual-processor boards for a total maximum of 30 processors.<ref name="cs.berkeley.edu"/><ref name="unixreview198604_sequent">{{ cite magazine | url=https://archive.org/details/sim_unix-review_1986-04_4_4/page/79/mode/1up | title=Growth in Balance | magazine=UNIX Review | date=April 1986 | access-date=24 June 2022 | pages=79–80 }}</ref>

The systems ran a modified version of [[Berkeley Software Distribution|4.2BSD]] [[Unix]] the company called [[DYNIX]], for DYNamic unIX. The machines were designed to compete with the [[Digital Equipment Corporation|DEC]] [[VAX-11/780]], with all of their inexpensive processors available to run any process. In addition the system included a series of libraries that could be used by programmers to develop applications that could use more than one processor at a time.

===Symmetry===
Their next series was the [[Intel 80386]]-based Symmetry, released in 1987. Various models supported between 2 and 30 processors, using a new [[write-back cache|copy-back cache]] and a wider [[64-bit]] [[Front side bus|memory bus]]. 1991's Symmetry 2000 models added multiple [[SCSI]] boards, and were offered in versions with from one to six [[Intel 80486]] processors. The next year they added the [[VMEbus]] based Symmetry 2000/x50 with faster CPUs.

[[File:Sequent S81.jpg|thumb|right|Sequent S81 system]]
The late 1980s and early 1990s saw big changes on the software side for Sequent. DYNIX was replaced by DYNIX/ptx, which was based on a merger of [[AT&T Corporation]]'s [[UNIX System V]] and [[Berkeley Software Distribution|4.2BSD]]. And this was during a period when Sequent's high-end systems became particularly successful due to a close working relationship with [[Oracle Corporation|Oracle]], specifically [[Oracle database|their high-end database servers]]. In 1993 they added the Symmetry 2000/x90 along with their ptx/Cluster software, which added various [[High-availability cluster|high availability]] features and introduced custom support for [[Oracle Parallel Server]].

In 1994 Sequent introduced the Symmetry 5000 series models SE20, SE60 and SE90, which used 66&nbsp;MHz [[Pentium (original)|Pentium]] CPUs in systems from 2 to 30 processors.<ref name=RICM/> The next year they expanded that with the SE30/70/100 lineup using 100&nbsp;MHz Pentiums,<ref name=RICM/> and then in 1996 with the SE40/80/120 with 166&nbsp;MHz Pentiums. A variant of the Symmetry 5000, the WinServer 5000 series, ran [[Windows NT]] instead of DYNIX/ptx.<ref name="winserver">{{cite web|url=http://www.allbusiness.com/technology/software-services-applications-computer/7126055-1.html|title=Sequent Unveils New High-End Systems for Windows NT; Based on Industry-Leading Platform Symmetry Platform|date=1995-05-23|work=[[Business Wire]]|accessdate=2009-03-23}}</ref>

===NUMA===
Recognizing the increase in competition for SMP systems after having been early adopters of the architecture, and the increasing integration of SMP technology into microprocessors, Sequent sought its next source of differentiation. They began investing in the development of a system based on a cache-coherent non-uniform memory architecture ([[ccNUMA]]) and leveraging [[Scalable Coherent Interconnect]]. NUMA distributes memory among the processors, avoiding the [[wikt:bottleneck|bottleneck]] that occurs with a single monolithic memory. Using NUMA would allow their multiprocessor machines to generally outperform SMP systems, at least when the tasks can be executed close to their memory &mdash; as is the case for [[Server (computing)|server]]s, where tasks typically do not share large amounts of data.

In 1996 they released the first of a new series of machines based on this new architecture. Known internally as STiNG, an [[abbreviation]] for ''Sequent: The Next Generation (with Intel inside)'', it was productized as NUMA-Q<ref name=NUMA.q>{{cite web | url=https://www.computerworld.co.nz/article/518203/auckland_university_first_buy_sequent_numa-q_box | archive-url=https://web.archive.org/web/20190623084303/https://www.computerworld.co.nz/article/518203/auckland_university_first_buy_sequent_numa-q_box | archive-date=2019-06-23 | title=IT news, careers, business technology, reviews }}</ref> and was the last of the systems released before the company was purchased by IBM for over $800 million.

<!-- Image with inadequate rationale removed: [[File:Project.monterey.jpg|right|thumb|125px|[[Project Monterey]].]] -->
IBM then started [[Project Monterey]] with [[Santa Cruz Operation]], intending to produce a NUMA-capable standardized [[Unix]] running on [[IA-32]], [[IA-64]] and [[IBM Power microprocessors|POWER]] and [[PowerPC]] platforms. This project later fell through as both IBM and SCO turned to the [[Linux]] market, but is the basis for "the new SCO"'s ''[[SCO v. IBM]]'' Linux lawsuit.

===IBM purchase and disappearance===
With their future product strategy in tatters, it appeared Sequent had little future standing alone, and was purchased by IBM in 1999 for $810 million.<ref>{{cite news |newspaper=Computerworld
|title=IBM drops Intel high-end server
|url=https://www.computerworld.com/article/2576139/network-servers/ibm-drops-intel-high-end-server.html |date=May 13, 2002}}</ref> IBM released several x86 servers with a  NUMA architecture. The first was the x440 in August, 2002 with a follow-on x445 in 2003. In 2004, an Itanium-based x455 was added to the NUMA family. During this period, NUMA technology became the basis for IBM's [[IBM System x|extended X-Architecture]] (eXA, which could also stand for enterprise X-Architecture). As of 2011, this chipset is now on its fifth generation, known as eX5 technology.<ref>{{cite web |url=http://www.ibm.com/systems/info/x86servers/ex5/ |title=IBM eX5 flexible enterprise systems: EX5 systems overview |website=www.ibm.com |access-date=22 May 2022 |archive-url=https://archive.today/20130125221915/http://www.ibm.com/systems/info/x86servers/ex5/ |archive-date=25 January 2013 |url-status=dead}}</ref><ref>{{cite web|url=http://www.redbooks.ibm.com/Redbooks.nsf/pages/xref?Open|title = XREF: System x Reference &#124; IBM Redbooks}}</ref> It now falls under the brand [[IBM System x]].

According to a May 30, 2002 article in the ''[[Wall Street Journal]]'' (WSJ) entitled "Sequent Deal Serves Hard Lesson for IBM":
:When IBM bought Sequent, ...it [Sequent] lacked the size and resources to compete with [[Sun Microsystems|Sun]] and [[Hewlett-Packard|Hewlett-Packard Co.]] in the Unix server market....
:In 1999, IBM had problems of its own with an aged and high-priced line of [[Server (computing)|server]]s, particularly for its version of Unix known as [[AIX operating system|AIX]]. It also faced huge losses in [[personal computer]]s and declining sales in its cash-cow [[Mainframe computer|mainframe line]].

==Detailed model descriptions==
The following is a more detailed description<ref>Sequent Computer Systems (1991). ''Symmetry Multiprocessor Architecture Overview''. Company publication number 1003-50113-01</ref> of the first two generations of Symmetry products, released between 1987 and 1990.

===Symmetry S-series===
;Symmetry S3: The S3 was the low-end platform based on commodity PC components running a fully compatible version of DYNIX 3. It featured a single 33&nbsp;[[Megahertz|MHz]] [[Intel 80386]] processor, up to 40 [[megabyte]]s of RAM, up to 1.8 [[gigabyte]]s of [[SCSI]]-based disk storage, and up to 32 direct-connected [[serial port]]s.<ref>{{cite web
   |date=February 24, 1994
   |url=http://www.cs.uoregon.edu/research/paraducks/papers/sc93.d/subsubsection3_3_2_3.html
   |title=The Sequent Symmetry}}</ref>
 
;Symmetry S16: The S16 was the entry-level multiprocessing model, which ran DYNIX/ptx. It featured up to six 20&nbsp;MHz Intel 80386 processors, each with a 128 [[kilobyte]] [[CPU cache|cache]]. It also supported up to 80&nbsp;MB of RAM, up to 2.5&nbsp;GB of SCSI-based disk storage, and up to 80 direct-connected serial ports.

;Symmetry S27: The S27 ran either DYNIX/ptx or DYNIX 3. It featured up to ten 20&nbsp;MHz Intel 80386 processors, each with a 128 KB cache. It also supported up to 128&nbsp;MB of RAM, up to 12.5&nbsp;GB of disk storage, and up to 144 direct-connected serial ports.<ref name=S27.81>{{Cite web|url=https://people.eecs.berkeley.edu/~culler/machines/sequent2.ps|title=Sequent Symmetry S27 and Symmetry S81 Parallel Bus Architecture}}</ref>

;Symmetry S81: The S81 ran either DYNIX/ptx or DYNIX 3. It featured up to 30 20&nbsp;MHz Intel 80386 processors, each with a 128 KB cache. It also supported up to 384&nbsp;MB of RAM, up to 84.8&nbsp;GB of disk storage, and up to 256 direct-connected serial ports.<ref name=S27.81/>

===Symmetry 2000 series===
;Symmetry 2000/40: The S2000/40 was the low-end platform based on commodity PC components running a fully compatible version of DYNIX/ptx. It featured a single 33&nbsp;[[Megahertz|MHz]] [[Intel 80486]] processor, up to 64 [[megabyte]]s of RAM, up to 2.4 [[gigabyte]]s of [[SCSI]]-based disk storage, and up to 32 direct-connected [[serial port]]s.

;Symmetry 2000/200: The S2000/200 was the entry-level multiprocessing model, which ran DYNIX/ptx. It featured up to six 25&nbsp;MHz Intel 80486 processors, each with a 512 [[kilobyte]] [[CPU cache|cache]]. It also supported up to 128&nbsp;MB of RAM, up to 2.5&nbsp;GB of SCSI-based disk storage, and up to 80 direct-connected serial ports.

;Symmetry 2000/400: The S2000/400 ran either DYNIX/ptx or DYNIX 3. It featured up to ten 25&nbsp;MHz Intel 80486 processors, each with a 512 KB cache. It also supported up to 128&nbsp;MB of RAM, up to 14.0&nbsp;GB of disk storage, and up to 144 direct-connected serial ports.

;Symmetry 2000/700: The S2000/700 ran either DYNIX/ptx or DYNIX 3. It featured up to 30 25&nbsp;MHz Intel 80486 processors, each with a 512 KB cache. It also supported up to 384&nbsp;MB of RAM, up to 85.4&nbsp;GB of disk storage, and up to 256 direct-connected serial ports.

==See also==
*[[NCR Voyager]] (early 486/Pentium SMP systems)

==References==
{{Reflist|30em}}

==External links==
* {{web archive|url=https://web.archive.org/web/19980203152329/http://www.sequent.com/|title=Official website}}
{{Commons category-inline|Sequent Computer Systems}}

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