 | |
| Industry | High-end computer hardware |
|---|---|
| Founded | 1983 |
| Defunct | 1999 |
| Fate | Acquired |
| Successor | IBM |
| Website | sequent.com at theWayback Machine (archived 1998-02-03) |
Sequent Computer Systems, Inc. was a computer company that designed and manufacturedmultiprocessingcomputer systems. They were among the pioneers in high-performancesymmetric multiprocessing (SMP)open systems, innovating in both hardware (e.g.,cache management andinterrupt handling) and software (e.g.,read-copy-update).
Through a partnership withOracle Corporation, Sequent became a dominant high-endUNIX platform in the late 1980s and early 1990s. Later they introduced a next-generation high-end platform for UNIX andWindows NT based on anon-uniform memory access architecture, NUMA-Q. As hardware prices fell in the late 1990s, andIntel shifted their server focus to theItanium processor family, Sequent joined theProject Monterey effort in October 1998, which aimed to move a standard Unix to several new platforms.[1]
In July 1999 Sequent agreed to beacquired by IBM.[2] At the time, Sequent's CEO said its technology would "find its way through IBM's entire product field"[1] and IBM announced it would "both sell Sequent machines, and fold Sequent's technology...into its own servers",[2] 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.[3]
Vestiges of Sequent's innovations live on in the form of data clustering software fromPolyServe (subsequently acquired by HP),[4][5] various projects withinOSDL, IBM contributions to theLinux kernel, and claims in theSCO v. IBM lawsuit.[6][7][8][9][10]
Originally namedSequel,[11] Sequent was formed in 1983[12] when a group of seventeen engineers and executives leftIntel after the failediAPX 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,[13] then considered one of the up-and-coming fields in computer design.[14][15][16]
Sequent's first computer systems were the Balance 8000 (released in 1984) and Balance 21000 (released in 1986).[17] Both models were based on 10 MHzNational SemiconductorNS32032 processors, each with a small write-through cache connected to a common memory to form ashared memory system. The Balance 8000 supported up to 6 dual-processor boards for a total maximum of 12 processors.[18][19][20] The Balance 21000 supported up to 15 dual-processor boards for a total maximum of 30 processors.[20][21]
The systems ran a modified version of4.2BSDUnix the company calledDYNIX, for DYNamic unIX. The machines were designed to compete with theDECVAX-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.
Their next series was theIntel 80386-based Symmetry, released in 1987. Various models supported between 2 and 30 processors, using a newcopy-back cache and a wider64-bitmemory bus. 1991's Symmetry 2000 models added multipleSCSI boards, and were offered in versions with from one to sixIntel 80486 processors. The next year they added theVMEbus based Symmetry 2000/x50 with faster CPUs.
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 ofAT&T Corporation'sUNIX System V and4.2BSD. And this was during a period when Sequent's high-end systems became particularly successful due to a close working relationship withOracle, specificallytheir high-end database servers. In 1993, they added the Symmetry 2000/x90 along with their ptx/Cluster software, which added varioushigh availability features and introduced custom support forOracle Parallel Server.
In 1994, Sequent introduced the Symmetry 5000 series models SE20, SE60 and SE90, which used 66 MHzPentium CPUs in systems from 2 to 30 processors.[12] The next year they expanded that with the SE30/70/100 lineup using 100 MHz Pentiums,[12] and then in 1996 with the SE40/80/120 with 166 MHz Pentiums. A variant of the Symmetry 5000, the WinServer 5000 series, ranWindows NT instead of DYNIX/ptx.[22]
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 leveragingScalable Coherent Interconnect. NUMA distributes memory among the processors, avoiding thebottleneck 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 — as is the case forservers, 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, anabbreviation forSequent: The Next Generation (with Intel inside), it was productized as NUMA-Q[23] and was the last of the systems released before the company was purchased by IBM for over $800 million.
IBM then startedProject Monterey withSanta Cruz Operation, intending to produce a NUMA-capable standardizedUnix running onIA-32,IA-64 andPOWER andPowerPC platforms. This project later fell through as both IBM and SCO turned to theLinux market, but is the basis for "the new SCO"'sSCO v. IBM Linux lawsuit.
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.[24] 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'sextended 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.[25][26] It now falls under the brandIBM System x.
According to a May 30, 2002 article in theThe Wall Street Journal (WSJ) entitled "Sequent Deal Serves Hard Lesson for IBM":
The following is a more detailed description[27] of the first two generations of Symmetry products, released between 1987 and 1990.
{{cite web}}: CS1 maint: archived copy as title (link)
Media related toSequent Computer Systems at Wikimedia Commons
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