Sequent Computer Systems - AbsoluteAstronomy.com

Sequent Computer Systems, or Sequent, was a computer company that designed and manufactured multiprocessing

Multiprocessing

Multiprocessing is the use of two or more central processing units within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them...

computer systems. They were among the pioneers in high-performance symmetric multiprocessing

Symmetric multiprocessing

In computing, symmetric multiprocessing involves a multiprocessor computer hardware architecture where two or more identical processors are connected to a single shared main memory and are controlled by a single OS instance. Most common multiprocessor systems today use an SMP architecture...

(SMP) open systems

Open system (computing)

Open systems are computer systems that provide some combination of interoperability, portability, and open software standards. The term was popularized in the early 1980s, mainly to describe systems based on Unix,...

, innovating in both hardware (e.g. cache

Cache

In computer engineering, a cache is a component that transparently stores data so that future requests for that data can be served faster. The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere...

management and interrupt

Interrupt

In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....

handling) and software (e.g. read-copy-update

Read-copy-update

In computer operating systems, read-copy-update is a synchronization mechanism implementing a kind of mutual exclusionPlease note that RCU does not implement mutual exclusion in the conventional sense: RCU readers can and do run concurrently with RCU updates...

).

Through a partnership with Oracle Corporation

Oracle Corporation

Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...

, Sequent became a dominant high-end UNIX

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

platform in the late 1980s and early 1990s. Later they introduced a next-generation high-end platform for UNIX and Windows NT

Windows NT

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...

based on a non-uniform memory access

Non-Uniform Memory Access

Non-Uniform Memory Access is a computer memory design used in Multiprocessing, where the memory access time depends on the memory location relative to a processor...

architecture, NUMA-Q. As hardware prices fell in the late 1990s, and Intel shifted their server focus to the Itanium

Itanium

Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...

processor family, Sequent joined the Project Monterey

Project Monterey

Project Monterey was an attempt to build a single Unix operating system that ran across a variety of 32-bit and 64-bit platforms, as well as supporting multi-processing...

effort in October 1998. which aimed to move a standard Unix to several new platforms.

In July 1999 Sequent agreed to be acquired by IBM. At the time, Sequent's CEO said its technology would "find its way through IBM's entire product field" and IBM announced it would "both sell Sequent machines, and fold Sequent's technology...into its own servers", 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.

Vestiges of Sequent's innovations live on in the form of data clustering software from PolyServe, various projects within OSDL

OSDL

Open Source Development Labs was a non-profit organization supported by a global consortium tasked to "accelerate the deployment of Linux for enterprise computing." Founded in 2000, its goals included "to be the recognized center-of-gravity for the Linux industry."On January 22, 2007, OSDL and the...

, IBM contributions to the Linux kernel

Linux kernel

The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....

, and claims in the SCO v. IBM

SCO v. IBM

SCO v. IBM is a civil lawsuit in the United States District Court of Utah. The SCO Group asserted that there are legal uncertainties regarding the use of the Linux operating system due to alleged violations of IBM's Unix licenses in the development of Linux code at IBM.-Summary:On March 6, 2003,...

lawsuit.

History

Originally named Sequel, Sequent was formed in 1983 when a group of seventeen engineers and executives left Intel after the failed iAPX 432

Intel iAPX 432

The Intel iAPX 432 was a commercially unsuccessful 32-bit microprocessor architecture, introduced in 1981.The project was Intel's first 32-bit microprocessor design, and intended to be the company's main product line for the 1980s. Many advanced multitasking and memory management features were...

"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, then considered one of the up-and-coming fields in computer design.

Balance

Sequent's first computer systems were the Balance 8000 (released in 1984) and Balance 21000 (released in 1986).The Balance 8000 got its name from the original design to support up to 8 processors. The Balance 21000 included up to thirty 10 MHz National Semiconductor

National Semiconductor

National Semiconductor was an American semiconductor manufacturer, that specialized in analog devices and subsystems,formerly headquartered in Santa Clara, California, USA. The products of National Semiconductor included power management circuits, display drivers, audio and operational amplifiers,...

NS32032 processors (in multiples of 2), each with a small write-through cache connected to a common memory to form a shared memory

Shared memory

In computing, shared memory is memory that may be simultaneously accessed by multiple programs with an intent to provide communication among them or avoid redundant copies. Depending on context, programs may run on a single processor or on multiple separate processors...

system. The model number 21000 came from a simple calculation of the relative performance of the NS32032 (0.7MIPS

MIPS

MIPS may refer to:* Maharana Institute of Professional Studies, an institution in Kanpur, Uttar Pradesh, India* Mansehra International Public School and College, in Mansehra, Pakistan* Material input per unit of service, an economic efficiency indicator...

) times 30 processors: 21 MIPs. Originally, Balance systems were equipped with a SCSI

SCSI

Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...

cartridge tape drive, Multibus

Multibus

Multibus is a computer bus standard used in industrial systems. It was developed by Intel Corporation and was adopted as the IEEE 796 bus.The Multibus specification was important because it was a robust, well-thought out industry standard with a relatively large form factor so complex devices could...

for the hard drives and 6250 bpi reel tape device and Ethernet

Ethernet

Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

for networking. Later, with the introduction of the Balance 21000, faster Storage Module Device

Storage Module Device

Storage Module Device was a family of storage devices first shipped by Control Data Corporation in December 1973 as the CDC 9760 40 MB storage module disk drive. The CDC 9762 80 MB variant was announced in June 1974 and the CDC 9764 150 MB and the CDC 9766 300 MB variants were announced in 1975...

disks replaced the old Multibus drives. The SMD-based disk controller was called ZDC, because it was designed by a fellow by the name of Zeke. Thus, ZDC stood for Zeke's Disk Controller. In a small company such as Sequent, it was not unusual for one person to be primarily (if not solely) responsible for major component designs. The systems ran a modified version of 4.2BSD

Berkeley Software Distribution

Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...

Unix

the company called DYNIX

Dynix

Dynix is an operating system developed by Sequent. It is a flavor of Unix based on BSD. DYNIX was replaced by DYNIX/ptx, which was based on the System V version of UNIX produced by AT&T....

, for DYNamic unIX. The machines were designed to compete with the DEC

Digital Equipment Corporation

Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

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. The Balance systems were originally intended to be sold to OEMs as computing engines, (initial super workstation designs did not support shared memory according to Ron Parsons), but that market could not be developed. When the commercial market discovered their reliability, scalable performance and cost advantages, the company re-thought its marketing strategy. The Balance line sold well for three years to banks, the aerospace industry, the government, other commercial enterprises, and universities interested in parallel computing

Parallel computing

Parallel computing is a form of computation in which many calculations are carried out simultaneously, operating on the principle that large problems can often be divided into smaller ones, which are then solved concurrently . There are several different forms of parallel computing: bit-level,...

Symmetry

Their next series was the Intel 80386

Intel 80386

The Intel 80386, also known as the i386, or just 386, was a 32-bit microprocessor introduced by Intel in 1985. The first versions had 275,000 transistors and were used as the central processing unit of many workstations and high-end personal computers of the time...

-based Symmetry, released in 1987. Various models supported between 2 and 30 processors, using a new copy-back cache and a wider 64-bit

64-bit

64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...

memory bus

Front side bus

A front-side bus is a computer communication interface often used in computers during the 1990s and 2000s.It typically carries data between the central processing unit and a memory controller hub, known as the northbridge....

. 1991's Symmetry 2000 models added multiple SCSI

SCSI

boards, and were offered in versions with from one to six Intel 80486

Intel 80486

The Intel 80486 microprocessor was a higher performance follow up on the Intel 80386. Introduced in 1989, it was the first tightly pipelined x86 design as well as the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating point unit...

processors. The next year they added the VMEbus

VMEbus

VMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...

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 of AT&T

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

's UNIX System V

UNIX System V

Unix System V, commonly abbreviated SysV , is one of the first commercial versions of the Unix operating system. It was originally developed by American Telephone & Telegraph and first released in 1983. Four major versions of System V were released, termed Releases 1, 2, 3 and 4...

and 4.2BSD

Berkeley Software Distribution

Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...

. And this was during a period when Sequent's high-end systems became particularly successful due to a close working relationship with Oracle

Oracle Corporation

, specifically their high-end database servers

Oracle database

The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....

. In 1993 they added the Symmetry 2000/x90 along with their ptx/Cluster software, which added various high availability

High-availability cluster

High-availability clusters are groups of computers that support server applications that can be reliably utilized with a minimum of down-time. They operate by harnessing redundant computers in groups or clusters that provide continued service when system components fail...

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 MHz Pentium CPUs in systems from 2 to 30 processors. The next year they expanded that with the SE30/70/100 lineup using 100 MHz Pentiums, and then in 1996 with the SE40/80/120 with 166 MHz Pentiums. A variant of the Symmetry 5000, the WinServer 5000 series, ran Windows NT

Windows NT

instead of DYNIX/ptx.

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

Scalable Coherent Interconnect

SCI, for Scalable Coherent Interface, is a high-speed interconnect standard for shared memory multiprocessing and message passing. The IEEE Std 1596-1992, IEEE Standard for Scalable Coherent Interface was approved by the IEEE standards board on March 19, 1992...

. NUMA distributes memory among the processors, avoiding the bottleneck

Bottleneck

A bottleneck is a phenomenon where the performance or capacity of an entire system is limited by a single or limited number of components or resources. The term bottleneck is taken from the 'assets are water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width...

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 for server

Server (computing)

In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

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

Abbreviation

An abbreviation is a shortened form of a word or phrase. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase...

for Sequent: The Next Generation (with Intel inside), it was productized as NUMA-Q and was the last of the systems released before the company was purchased by IBM for over $800 million.

IBM then started Project Monterey

Project Monterey

Project Monterey was an attempt to build a single Unix operating system that ran across a variety of 32-bit and 64-bit platforms, as well as supporting multi-processing...

with Santa Cruz Operation, intending to produce a NUMA-capable standardized Unix

Unix

running on IA-32

IA-32

IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...

, IA-64 and POWER

IBM POWER

POWER is a reduced instruction set computer instruction set architecture developed by IBM. The name is an acronym for Performance Optimization With Enhanced RISC....

and PowerPC

PowerPC

PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...

platforms. This project later fell through as both IBM and SCO turned to the Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

market, but is the basis for "the new SCO"'s SCO v. IBM

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. IBM released several x86 servers based on Sequent's 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, the NUMA technology became the basis for IBM's extended X-Architecture

IBM System x

The IBM System x computers form a sub-brand of International Business Machines System brand servers...

(eXA, which could also stand for enterprise X-Architecture). As of 2011, this chipset is now on its fifth generation, known as eX5 technology. It now falls under the brand IBM System x

IBM System x

The IBM System x computers form a sub-brand of International Business Machines System brand servers...

.

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

Sun Microsystems

Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

and Hewlett-Packard Co.

Hewlett-Packard

Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

in the Unix server market....

In 1999, IBM had problems of its own with an aged and high-priced line of server

Server (computing)

s, particularly for its version of Unix known as AIX

AIX operating system

AIX AIX AIX (Advanced Interactive eXecutive, pronounced "a i ex" is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms...

. It also faced huge losses in personal computer

Personal computer

A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

s and declining sales in its cash-cow mainframe line

Mainframe computer

Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

. Robert Stephenson, who headed the server group at IBM, saw acquiring Sequent as the best route to make IBM competitive in the market for large Unix servers where Sun was gobbling up market share.

When Stephenson retired shortly after IBM completed its acquisition of Sequent, responsibility for servers fell on Samuel J. Palmisano

Samuel J. Palmisano

Samuel J. Palmisano was president and chief executive officer of IBM, which as of 2009 was the largest IT company in the world and 45th largest company overall. He was elected chairman in October 2002, effective January 1, 2003, and has served as CEO since March 2002. Before he became CEO,...

. The WSJ article noted that Palmisano wanted to "simplify IBM's multipronged server strategy"; it also quoted Scott Gibson, one of three executives (along with Casey Powell and Larry Wade) who led Sequent when it was founded. Gibson told the WSJ the acquisition was doomed because "the guy who sponsored the acquisition retired."

An alternative view of IBM's actions, born out of the belief that corporations maintain consistent strategies over the short and medium term despite executive changes, is that IBM acquired Sequent not to nurture it but simply to keep it out of Sun's clutches. Through its acquisition of what became the Enterprise 10000 server line from Cray, Sun had done so much financial damage to IBM's server market share, that IBM was very reluctant to see this disaster repeated. Even if it generated zero revenue for IBM, the net present value of Sequent from IBM's viewpoint was higher inside IBM than inside Sun.

Detailed model descriptions

The following is a more detailed description 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 MHz Intel 80386

Intel 80386

processor, up to 40 megabyte

Megabyte

The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...

s of RAM, up to 1.8 gigabyte

Gigabyte

The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...

s of SCSI

SCSI

-based disk storage, and up to 32 direct-connected serial port

Serial port

In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...

s. S3 derived its name from having a single, 3 MIP processor (relative to its larger siblings with a faster bus and more sophisticated cache).

Symmetry S16: The S16 was the entry-level multiprocessing model, which ran DYNIX/ptx. It featured up to six 20 MHz Intel 80386 processors, each with a 128 kilobyte

Kilobyte

The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...

cache

Cache

. It also supported up to 80 MB of RAM, up to 2.5 GB of SCSI-based disk storage, and up to 80 direct-connected serial ports. S16 was so named as it was initially designed for just 4 processors of 4 MIPs each (16 Mhz 30386) with copy-back cache.

Symmetry S27: The S27 ran either DYNIX/ptx or DYNIX 3. It featured up to ten 20 MHz Intel 80386 processors, each with a 128 KB cache. It also supported up to 128 MB of RAM, up to 12.5 GB of disk storage, and up to 144 direct-connected serial ports. S27 derived its name from the estimated MIP rating based on having ten 16 MHz processors at 3 MIPs each (early models still had write-through cache), and then taking 10% off the total to account for possible performance rolloff.

Symmetry S81: The S81 ran either DYNIX/ptx or DYNIX 3. It featured up to 30 20 MHz Intel 80386 processors, each with a 128 KB cache. It also supported up to 384 MB of RAM, up to 84.8 GB of disk storage, and up to 256 direct-connected serial ports. S81 derived its name from the estimated MIP rating based on having thirty processors at 3 MIPs each (early models still had write-through cache), and then taking 10% off the total to account for possible performance rolloff. Once copy-back cache was available, the MIPs rating was revised to 4 for the 16 MHz 80386 chip. However there was no effort to change the model numbers to reflect this higher performance potential.

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 MHz Intel 80486

Intel 80486

processor, up to 64 megabyte

Megabyte

s of RAM, up to 2.4 gigabyte

Gigabyte

The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...

s of SCSI

SCSI

-based disk storage, and up to 32 direct-connected serial port

Serial port

In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...

s.

Symmetry 2000/200: The S2000/200 was the entry-level multiprocessing model, which ran DYNIX/ptx. It featured up to six 25 MHz Intel 80486 processors, each with a 512 kilobyte

Kilobyte

cache

Cache

. It also supported up to 128 MB of RAM, up to 2.5 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 MHz Intel 80486 processors, each with a 512 KB cache. It also supported up to 128 MB of RAM, up to 14.0 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 MHz Intel 80486 processors, each with a 512 KB cache. It also supported up to 384 MB of RAM, up to 85.4 GB of disk storage, and up to 256 direct-connected serial ports.

External links

Project Blue-Away, a Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

project announced in February 2002 targeting NUMA-Q customers
IBM lays off 200 Portland employees, a January 2002 article, also from Portland Business Journal
Out of Sequence, a September 1999 article from Willamette Week
Willamette Week
Willamette Week is an alternative weekly newspaper published in Portland, Oregon, United States. It features reports on local news, politics, sports, business and culture....

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.