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Results for Tandem Computers
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(aerospace engineering) The fore and aft configuration used in boosted missiles, long-range ballistic missiles, and satellite vehicles; stages are stacked together in series and are discarded at burnout of the propellant for each stage.
(electricity) Two-terminal pair networks are in tandem when the output terminals of one network are directly connected to the input terminals of the other network.
Type: Public Company
Address: 19333 Vallco Parkway, Cupertino, California 95014-2599, U.S.A.
Telephone: (408) 285-6000
Fax: (408) 285-6635
Employees: 11,167
Sales: $1.92 billion
Stock Exchanges: New York Midwest Pacific
Incorporated: 1974
Tandem Computers, Inc., specializes in multiple processor computer systems used by banks, commodities exchanges, telecommunications companies, and other businesses that cannot afford even brief computer failures.
Tandem was founded in November 1974 by a group of former Hewlett-Packard employees headed by James G. Treybig. Convinced that one of the greatest needs among banks and other potential customers was for computers that never failed, Treybig proposed a 'fault-tolerant' computer with two or more central processors working independently; if one processor failed, its work could be transferred to the other processors and the computer would not experience downtime. Treybig tried to interest Hewlett-Packard in manufacturing this computer, but the firm declined. Consequently, he left to pursue it on his own and spent several months at Kleiner & Perkins, a San Francisco venture capital firm, plotting his strategy.
In 1974 Thomas J. Perkins, a former Hewlett-Packard executive, and Eugene Kleiner, a cofounder of Fairchild Semiconductor, invested $50,000 in Treybig's idea, and Tandem was formed. Treybig hired Michael D. Green as Tandem's vice president of software development and also employed James A. Katzman, who had designed one of Hewlett-Packard's largest computers. Once Green and Katzman had developed the hardware and software combination to use for the Tandem computer, Kleiner and Perkins invested another $1 million and an additional $500,000 later in 1975. Tandem also attracted $1.5 million from other venture capital sources that year.
During this time, computer failures were a serious problem, with most large computer systems suffering hardware failures at least once a year. Tandem developed its Guardian software to 'watch' the system and transfer operations if one of the processors failed. In addition, Tandem designed the 'NonStop computer' so that any component could be replaced without turning off the entire system. Finally, since reliability was its biggest selling point, Tandem tested its products more extensively than most firms before shipping the first models of its NonStop computer in 1976.
Banks, stock exchanges, manufacturers, and other businesses found Tandem's reliability indispensable. They also liked the fact that Tandem's computers could be linked together without any software changes, enabling clients to start with a two-processor system and add more processors as their needs grew. In deciding to focus on fault-tolerant computers, the firm had found a niche in which it essentially had no rivals until the early 1980s. Sales took off and doubled every year for the first six years of Tandem's existence. The firm went public in 1977, and sales rose from $56 million in 1979 to $312 million in 1982.
Tandem initially managed to accomodate its rapid growth by forming a unique corporate culture. By 1982 Tandem had about 3,000 employees. Tandem employees were offered flexible work hours, stock options plans, sabbaticals every four years, and promotion-from-within opportunities. The Cupertino headquarters featured a swimming pool, and many of the employees attended 'beer busts' each Friday to encourage communication across departmental lines. Furthermore, many important management decisions were made by consensus, and because Treybig disapproved of long meetings like those he had attended at Hewlett-Packard, almost none were held. These policies may have helped contribute to one of the lowest turnover levels as well as one of the highest productivity rates in the computer industry. Since talented personnel were in short supply in the Silicon Valley, a low turnover rate was essential to a company's success.
At the beginning of the 1980s a NonStop system consisted of anywhere from two to 16 processors. Each 16 bit-per-word processor could have up to two million bytes of main memory attached to it. Systems ranged in price from $120,000 for the smallest two-processor system to about $2.7 million for the largest systems using 10 to 14 processors. Tandem's proprietary software, sold at an additional charge, was crucial to their computers' efficiency. Guardian, the basic operating system, watched for and responded to component failures, and handled basic functions such as the scheduling of tasks and allocation of computing power. The database management system Enscribe handled files of up to four billion characters. Expand, a networking package, allowed users to interconnect Tandem computers at up to 255 separate locations. Tandem also offered two types of programming software: Encompass, designed to speed the writing of online transaction-processing applications, and Enform, an English-like language used to get information from databases. The Tandem computer also supported such high-level languages as Fortran, Cobol, and T/TAL.
Tandem's monopoly of fault-tolerant computers was jeopardized in the 1980s. Stratus Computer developed a four-processor computer and actively challenged Tandem in 1982. Hewlett-Packard, IBM, and Digital Equipment Corporation were also developing high-reliability computers. Furthermore, the U.S. economy was in recession, and Tandem experienced its first quarter of shrinking sales in mid-1982. That year, Tandem announced sales of $336 million. However, some shipments had been recorded that were not actually completed until after midnight of the last day of the year. As a result of this and other revenue recognition issues, the firm was forced to revise its sales figures to $312 million, embarrassing the company and leading to an investigation by the Securities and Exchange Commission. The investigation produced charges of fraud, but the case was settled without penalties or fines. In the spring of 1984, the entire computer industry went into a downturn, and Tandem's earnings fell 80 percent.
As a result of these problems, Tandem tightened its internal controls and refocused attention on strong, more centralized management. Treybig became more detail-oriented, holding top executives accountable for performance at weekly staff meetings and quarterly staff reviews. Rather than seeking consensus on every issue, Treybig began issuing orders. An audit team and a new marketing group were created, new hiring was frozen, and salary increases were stopped for six months. Treybig also cut back on overhead and research spending and moved Tandem toward data delivery as well as data processing, trying to broaden the firm's base.
The Infosat service started in 1983 with American Satellite Co. made Tandem the first computer manufacturer to combine satellite communications with its products.
Furthermore, Tandem bought equity positions in Triplex, a factory automation firm, and Integrated Technology, Inc., a telecommunications company. In 1985 Tandem began working to increase the availability and compatibility of its computers. The firm started a strategic alliance with Altos Computer Systems, which specialized in the Unix operating system favored in many U.S. government contracts. Tandem also sought to expand its market to include retailers as well as transportation and telephone companies.
Much of this effort was an attempt to lessen the firm's reliance on banking and financial services customers. Fifteen stock exchanges, including the New York Stock Exchange, and 30 brokerage firms worldwide used Tandem computers by mid 1986, but that market was relatively narrow and the competition was gaining. Tandem therefore broadened its product range to include workstations and mainframes. To aid in its market expansion, Tandem's sales force was increased and the marketing department revamped.
Sales for 1985 were $624 million; by 1987, with the company temporarily back on track, sales rose to $1,035 billion. At this time Tandem had about 7,000 employees in 150 offices worldwide, but with the computer market turning increasingly toward smaller computers, sales flagged for the large machines in which Tandem still specialized. The company also had trouble completing software for its smaller computers, such as the CLX system it unveiled in 1987. Its profits fell, its stock plunged, and rumors of a takeover circulated.
During this time the computer market was changing. Increased cooperation among manufacturers produced more compatible hardware and more widely accepted standards, and Tandem's reliance on unique software limited the company's sales. In 1987 Tandem lost a $1 billion U.S. Army contract for a hospital information system partly because its computers did not use the popular Unix operating system. Tandem began selling other companies' Unix systems and IBM-compatible PCs later that year. Treybig also decided to make Tandem's computers more compatible with other manufacturers. He saw an opening in corporate computer networks, serving 'live data' to financial and market analysts and others needing immediate knowledge of markets and financial information.
In June 1988 Tandem sought an immediate increase in its networking position with the purchase of Ungermann-Bass, Inc. for $271.4 million. Ungermann was a leading firm in the local area network market, and Tandem wanted that firm's expertise to help it tie its computers to those of other manufacturers. Tandem formed other partnerships to increase its networking strength, including Sybase, Inc., which it used to link open networks with its own computers. Tandem also began working with Systems Center, Inc. on an extensive network management system for Tandem computers, and in 1991 it acquired a 7.5 percent equity stake in System Integrators, Inc.
Seeking to compete with IBM directly, Tandem worked on a line of mainframe computers designed to perform the huge number-crunching jobs that IBM mainframes had been performing on data collected by Tandem's computers. In June 1989 Tandem announced relational database software that enabled its computers to perform mainframe-sized data analysis jobs. Partly on the strength of this software, it was awarded a four-year $50 million contract from the California Motor Vehicles Department, beating out IBM. In the fall of 1989 Tandem released the NonStop Cyclone, which sold for about one-third of an equivalent IBM system. It immediately won important customers like Humana, Inc. and Kaiser Permanente, two of the largest health maintenance organizations in the United States, and McKesson Corp., a multi-billion-dollar drug distributor. In 1990 Tandem announced that it would develop a new line of fault-tolerant Unix computers. That line, Tandem's Integrity S2, found a market in telecommunications, where it was used by AT&T, regional Bell operating companies, and other telephone companies.
Although sales for 1990 reached $1.87 billion, profits grew only slightly from $184.3 to $188.7 million. In 1991 the sales-to-profit ratio was worse, with sales increasing slightly to $1.92 billion and profits falling to $59.1 million. Much of the world was in an economic slowdown, and many companies cut back on capital expenses like computer systems. At the same time increases in technology made possible computers with more power for less money. So though its sales were strong, Tandem's margins and profits shrunk. To cut costs and raise profits, Tandem began reducing its work force. It also delayed salary increases for six months and ordered its U.S. employees to take three days vacation without pay in each of the first two quarters of 1992.
Nevertheless, the firm remained strong in telecommunications, partly through subsidiary Tandem Telecommunications Systems, Inc. To further bolster its telecommunications strength, Tandem bought software developer Applied Communications, Inc. in 1991. To remain competitive, Tandem began pushing RISC (reduced instruction-set computing) computers, which break down complex operations into simpler operations that can be performed quickly. RISC models were manufactured in the NonStop and Integrity lines, doubling the price-to-performance ratio while remaining compatible with previous models. Tandem marketed these models, the Cyclone/R and the CLX/R, to existing customers as well as those in new markets closed to Tandem in the past.
In April 1991 Tandem annouced its Tandem Image Processing System. Originally designed for the large trucking firm Consolidated Freightways, Inc., the system allowed receipts and other paperwork to be stored as digitized images on hard disk drives and optical disks. Tandem also released software allowing different companies to exchange business documents through electronic mail. The company's goals in the 1990s include, in the words of Treybig and Perkins, 'extending our leadership in price/performance, open networking, and continuous availability, and working ... to develop solutions optimized for our customers' critical business requirements.'
Principal Subsidiaries
Ungermann-Bass, Inc.; Applied Communications, Inc.; Array Technology Corp.; Mpact EDI Systems, Inc.; Tandem Telecommunications Systems, Inc.
Further Reading
'A Computer that Won't Shut Down,' Business Week, December 8, 1975.
Wiegner, Kathleen K., 'Beyond the Better Mousetrap,' Forbes, June 22, 1981.
Magnet, Myron, 'Managing by Mystique at Tandem Computers,' Fortune, June 28, 1982.
'An Acid Test for Tandem's Growth,' Business Week, February 28, 1983.
'Linking Up a Computer and Satellite System,' Business Week, May 24, 1983.
Malone, Michael, The Big Score, Doubleday, 1985.
'The Education of James Treybig,' Forbes, June 30, 1986.
Madden, Stephen J., 'How Jimmy Treybig Turned Tough,' Fortune, May 25, 1987.
'Why Tandem Struggles While Its Market Sizzles,' Business Week, August 22, 1988.
'This Cyclone Is Out to Rain on IBM's Parade,' Business Week, October 23, 1989.
Annual Report, Tandem Computers, Inc., 1991.
— Scott M. Lewis
Tandem Computers was an early manufacturer of fault tolerant
computer systems, marketed to the growing number of
Tandem Computers was founded in 1974 by a group of engineers from Hewlett-Packard: James Treybig, Mike Green, Jim Katzman, and Jack Loustaunou. Their business plan called for systems that were safe from "single-point failures" that were only slightly more expensive than competing non-fault tolerant systems. Tandem considered this to be very important to their business model. Limiting the additional expense was important since customers often developed procedural solutions to failures when the price of fault tolerant hardware was too high.
The first system was the Tandem/16 or T/16 (later called NonStop I after the introduction of its successor, the NonStop II). The system design was complete in 1975, and the first example was sold to Citibank in 1976. The machine consisted of between 2 and 16 processors, each capable of about 0.7 MIPS with their own memory, I/O buses, and dual connections to their custom inter-CPU computer bus, Dynabus. The modules were constructed with dual paths so that any single failure would always leave at least one bus (both I/O and Dynabus), free for use by the other modules. The CPU was influenced by the HP3000 CPU, a microprogrammed 16-bit stack-based machine with 16-bit user addressing. Like the HP3000, the NonStop CPU added a number of registers for fast access, such as base addresses for global and local variables.
The Tandem NonStop series ran a custom operating system, initially called T/TOS (Tandem Operating System), later Guardian, and finally NonStop Kernel. It supported a "NonStop" programming paradigm that allowed a program to be completely fault tolerant. Several other companies introduced failover technologies but only Guardian supported completely fail-safe transaction processing. A properly constructed Guardian program could fail at any point and resume transaction processing without any loss of data.
While conventional systems of the era, including mainframes, had failure rates on the order of a few days, the NonStop system was designed to fail 100 times less, with "uptimes" measured in years. Nevertheless the NonStop was deliberately designed to be price-competitive with conventional systems, with a simple 2-CPU system priced at just over two times that of a competing single-processor mainframe, as opposed to four or more times of most competing solutions.
NonStop I was followed by the NonStop II in 1981, a slight improvement in speed to 0.8 MIPS, but a more measurable upgrade in memory from a maximum of 1 MB per CPU in the later versions of the NonStop I, to 2 MB in the II, and the addition of a revamped virtual memory system allowing for considerably larger address spaces. The NonStop I was limited to 4 virtual memory segments (System Data, System Code, User Data, User Code) each limited to 128 kB in size.
The NonStop II increased the number of memory maps from 4 to 16, 8 of which were used for I/O, and provided a 32 bit address mode with user-accessible "extended segments" virtually unlimited in size. The same basic system, including the physical packaging, was used in 1983's NonStop TXP system that more than doubled the speed to 2.0 MIPS, and increased the physical memory to 8 MB. In all of these machines the same Dynabus system was used, which had been overdesigned in the NonStop I so they could avoid changing it in the future.
Introduced along with the TXP was a new
The company attempted to grab a piece of the rapidly-growing personal computer market in 1985 with its introduction of the MS-DOS based Dynamite PC/workstation. Sadly, numerous design compromises (include a unique 8086-based hardware platform incompatible with expansion cards of the day and extremely limited compatibility with IBM-based PC's) relegated the Dynamite to serving primarily as a smart terminal. It was quietly withdrawn from the market within a short period of time.
In 1986 a major upgrade to the system was introduced, the NonStop VLX. VLX used a new Dynabus, increasing speed from 13 Mbit/s to 40 Mbit/s (total, 20 Mbit/s per independent bus). They also introduced FOX II, increasing the size of the networks from 1 km to 4 km. Using the original FOX VLX systems could be used with the older NonStop II and TXP's, but these systems were not supported on FOX II.
VLX was partnered with the NonStop CLX, a minicomputer sized machine for smaller installations. The CLX had roughly the same performance as the earlier TXP, but was much smaller and less expensive. By the end of its lifetime the CLX had increased in speed considerably, and competed with the VLX, 1991's CLX 800 was only about 20% slower than the VLX, with the main difference being more limited expansion abilities.
In 1986 Tandem also introduced the first fault-tolerant SQL database, NonStop SQL. Developed totally in-house, NonStop SQL included a number of features based on Guardian to ensure data validity across nodes. NonStop SQL was famous for scaling linearly in performance with the number of nodes added to the system, whereas most databases of the era had performance that plateaued quite quickly, often after two CPUs. A later version released in 1989 added transactions that could be spread over nodes, a feature that remained unique for some time. Later, the SQL database group was first co-opted then absorbed into Microsoft's SQL development effort. One outcome of this collaboration was Microsoft's clustered system technology.
The NonStop Cyclone was introduced in 1989, introducing a new superscalar CPU design. It was otherwise similar to earlier systems, although much faster. In general terms the Cyclone was about four times as fast as the CLX 800, which Tandem used as their benchmark. On the downside the new CPU was complex and expensive, requiring four circuit boards to implement a single CPU.
In 1991 Tandem followed this with RISC-implementations of Guardian, running on MIPS R3000-based CPU modules in the Cyclone/R and CLX/R. Programs written for the earlier stack-based CPU design were automatically translated on the fly into R3000 code in an interpreter, although they ran considerably slower than on earlier machines. Tandem also provided a number of tools to easily port existing object code to the new systems, resulting in code that was some 25% slower than the original Cyclone. Source code compilers were also available. While slower, the new system was considerably less expensive, and it was clear that RISC performance was outpacing CISC. By making the move when they did, they were banking on increases in MIPS performance quickly wiping out any performance disadvantages the system had at the time. In 1993 the NonStop Himalaya K-Series using the MIPS R4400 was shipped.
In 1997 Tandem introduced the NonStop Himalaya S-Series. The S-Series machines were the first systems that changed the underlying architecture of the NonStop family, basing both the I/O and inter-CPU communication on their new ServerNet interconnect. Whereas Dynabus and FOX linked the CPU's together into a ring network, ServerNet was a true point-to-point network replacing both, and ran at much higher speeds. ServerNet later was used as the basis of the InfiniBand industry standard. The S-Series machines continued the use of MIPS processors, including the R4400 and R10000.
All the more recent systems were based on microprocessors, and the internal circuits of these chips are not fully checked. To assure correct computation, each logical processor had two microprocessors operating in lockstep. If the results coming out ever disagreed, the processor was considered to be faulting and instantly stopped. At that point Guardian would move that task to another processor as in earlier systems, guaranteeing that bad data was never written out due to hardware failures.
A different approach was used in a separate family of computers, the Integrity line. These computers used additional redundant CPUs running the same instruction stream. When a fault was detected (e.g. by lockstep mismatch), the failing module was disabled but the redundant module continued processing the instruction stream without interruption. Since this was handled primarily in hardware, it could be used with a slightly modified conventional operating system; Integrity used a Unix variant rather than Guardian. The line was introduced in 1989, apparently as a response to the machines of Stratus Technologies (which were remarketed by IBM as IBM System/88). Although distinct from the NonStop line, the Integrity designs were also based on the MIPS processors. With the introduction of the Integrity S4000 in 1995, the line was the first to use ServerNet and moved towards sharing hardware designs with the NonStop line.
Tandem was acquired by Compaq in 1997. Compaq was in turn acquired by HP in 2002, bringing Tandem back to its original roots. As of 2003, the NonStop product line continues to be produced, under the HP name.
After being acquired by HP, the NonStop line has moved to Itanium based processors, called Integrity NonStop Servers. The original Integrity line is no longer produced but the name 'Integrity' has been adopted by HP for all Itanium based servers.
The NonStop Kernel (NSK) can run multiple OS's. In addition to the Guardian OS, the modern NonStop platform incorporates a POSIX compatible environment (OSS) and Java. There is also an effort by HP to run Linux on the NonStop hardware.[1] Also, Linux or other Unix based operating systems could be installed on the NonStop platform via a virtual machine environment.
Tandem treated its employees with a great deal of respect, especially in the years leading to the company's first billion-dollar yearly sales figure. Innovative programs included:
As the company entered the 90's, however, sales and profits slowed, and many of these innovative programs were either curtailed or eliminated totally. By the end, Tandem was pretty much a company like any other in the computer field, culminating in the buyout by Compaq, who wasted little time eliminating almost all of these. Only beer bust, in a greatly watered down form (literally - many sites banned alcohol), survived.
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