Control Data Corporation

Control Data Corporation (CDC) was a supercomputer firm. For most of the 1960s, it built the fastest computers in the world by far, only losing that crown in the 1970s after Seymour Cray left the company to found Cray Research, Inc. (CRI). CDC was one of the nine major United States computer companies through most of the 1960s; the others were IBM, Burroughs Corporation, DEC, NCR, General Electric, Honeywell, RCA, and UNIVAC. CDC was well known and highly regarded throughout the industry at one time.

Background and origins: World War II–1957

During World War II the U.S. Navy had built up a team of engineers to build codebreaking machinery for both Japanese and German electro-mechanical ciphers. A number of these were produced by a team dedicated to the task working in the Washington, D.C., area. With the post-war wind-down of military spending the Navy grew increasingly worried that this team would break up and scatter into various companies, and it started looking for ways to covertly keep the team together.

Eventually they found their solution; the owner of a Chase Aircraft affiliate in St. Paul, Minnesota, John Parker, was about to lose all his contracts with the end of the war. The Navy never told Parker exactly what the team did, since it would have taken too long to get top secret clearance. Parker was obviously wary, but after several meetings with increasingly high-ranking Naval officers it became apparent that whatever it was, they were serious, and he eventually agreed to give this team a home in his military glider factory.

The result was Engineering Research Associates (ERA), a contract engineering company that worked on a number of seemingly unrelated projects in the early 1950s. One of these was one of the first commercial stored program computers, the 36-bit ERA 1103. The machine was built for the Navy, which intended to use it in their "above board" code-breaking centers. In the early 1950s a minor political debate broke out in Congress about the Navy essentially "owning" ERA, and the ensuing debates and legal wrangling left the company drained of both capital and spirit. In 1952 Parker sold ERA to Remington Rand.

Although Rand kept the ERA team together and developing new products, it was most interested in ERA's magnetic drum memory systems. Rand soon merged with Sperry Corporation to become Sperry Rand, and in the process of merging the companies, the ERA division was folded into Sperry's UNIVAC division. At first this did not cause too many changes at ERA, since the company was used primarily to provide engineering talent to support a variety of projects. However, one major project was moved from UNIVAC to ERA, the UNIVAC II project, which led to lengthy delays and upsets to nearly everyone involved.

Since the Sperry "big company" mentality encroached on the decision-making powers of the ERA founders, they left Sperry to form the Control Data Corp. in 1957, setting up shop in an old warehouse down the road from Sperry in Minneapolis at 501 Park Avenue. Of the members forming CDC, William Norris was the unanimous choice to become the chief executive officer of the new company. Seymour Cray was likewise chosen to be the chief designer, but he was still in the process of completing an early version of the 1103-based Naval Tactical Data System (NTDS), and he did not leave Sperry to join CDC until it was complete.

Early designs and Cray's big plan

CDC started business by selling subsystems, mostly drum memory systems, to other companies. Cray joined the next year, and he immediately built a small transistor-based 6-bit machine known as the "CDC Little Character" to test his ideas on large-system design and transistor-based machines. "Little Character" was a success, and CDC soon released a 48-bit transistorized version of their 1103 re-design as the CDC 1604 in 1959, with the first machine delivered to the U.S. Navy in 1960. Legend has it that the 1604 designation was chosen by adding CDC's first street address (501 Park Avenue) to Cray's former project, the ERA-Univac 1103.^[1] A 12-bit cut-down version was also released as the CDC 160A in 1960, arguably the first minicomputer. The 160A was particularly notable as it was built as a standard office desk item, which was a rather-unusual packaging for that era. New versions of the basic 1604 architecture were rebuilt into the CDC 3000 series, which sold through the early and mid-1960s.

Cray immediately turned to the design of a machine that would be the fastest (or in the terminology of the day, largest) machine in the world, setting the goal at 50 times the speed of the 1604. This required radical changes in design, and as the project "dragged on" — it had gone on for about four years by then — the management got increasingly upset and it demanded greater oversight. Cray in turn demanded (in 1962) to have his own remote lab, saying that otherwise, he would quit. Norris agreed, and Cray and his team moved to Cray's home town, Chippewa Falls, Wisconsin. Not even Bill Norris, the founder and president of CDC, could visit Cray's laboratory without an invitation. (See story of a salesman's uninvited visit to Chippewa Falls here.)

Peripherals business

Through the 1960s, Norris became increasingly worried that CDC had to develop a "critical mass" in order to compete with IBM. In order to do this, he started an aggressive program of buying up various companies to round out CDC's peripheral lineup. In general, they tried to offer a product to compete with any of IBM's, but running 10% faster and costing 10% less. This was not always easy to achieve.

One of its first peripherals was a tape transport, which led to some internal wrangling as the Peripherals Equipment Division attempted to find a reasonable way to charge other divisions of the company for supplying the devices. If the division simply "gave" them away at cost as part of a system purchase, they would never have a real budget of their own. Instead, a plan was established in which it would share profits with the divisions selling its peripherals, a plan eventually used throughout the company.

The tape transport was followed by the 405 Card Reader and the 415 Card Punch, followed by a series of tape drives and drum printers, all of which were designed in-house. The printer business was initially supported by Holley Carburetor in the Rochester, Michigan suburb outside of Detroit. They later formalized this by creating a jointly-held company, Holley Computer Products. Holley later sold its stake back to CDC, the remainder becoming the Rochester Division.

Norris was particularly interested in breaking out of the punched card–based workflow, where IBM held a stranglehold. He eventually decided to buy Rabinow Engineering, one of the pioneers of optical character recognition (OCR) systems. The idea was to bypass the entire punched card stage by having the operators simply type onto normal paper pages with a "known" typewriter font, and then submit those pages to the computer. Since a typewritten page contains much more information than a punched card (which has essentially one line of text from a page), this would offer savings all around. Unfortunately, this seemingly-simple task turned out to be much harder than anyone expected, and while CDC became a major player in the early days of OCR systems, it has remained a niche product to this day. Rabinow's plant in Rockville, MD was closed in 1976, and CDC left the business.

With the continued delays on the OCR project, it became clear that punched cards were not going to go away any time soon, and CDC had to address this as quickly as possible. Although the 405 remained in production, it was an expensive machine to build. So another purchase was made, Bridge Engineering, which offered a line of lower-cost as well as higher-speed card punches. All card-handling products were moved to what became the Valley Forge Division after Bridge moved to a new factory, with the tape transports to follow. Later on, the Valley Forge and Rochester divisions were spun off to form a new joint company with National Cash Register (later NCR Corporation), Computer Peripherals Inc (CPI), in order to share development and production costs across the two companies. ICL later joined the effort. Eventually the Rochester Division was sold to Centronics in 1982.

Another side-effect of Norris's attempts to diversify was the creation of a number of service bureaus that ran jobs on behalf of smaller companies that could not afford to buy computers. This was never very profitable, and in 1965, several managers suggested that the unprofitable centers be closed in a cost-cutting measure. Nevertheless, Norris was so convinced of the idea that he refused to accept this, and ordered an across-the-board "belt tightening" instead.

CDC 6600: defining supercomputing

CDC 6600

Meanwhile at the new Chippewa Falls lab, Seymour Cray, Jim Thornton, and Dean Roush put together a team of 34 engineers, which continued work on the new computer design. In 1964, this was released onto the market as the CDC 6600, out-performing everything on the market by roughly ten times. The 6600 had a CPU (Central Processing Unit) with multiple, asynchronous functional units, and it used 10 logical, external I/O processors to off-load many common tasks. That way the CPU could devote all of its time and circuitry to processing actual data, while the other controllers dealt with the mundane tasks like punching cards and running disk drives. Using late-model compilers, the machine attained a standard mathematical operations rate of 500 kilo-FLOPS, but handcrafted computer assemblies delivered about 1.0 mega-FLOPS. A simpler, much slower, and much less expensive version, implemented using a more traditional serial processor design rather than the 6600's parallel functional units, was released as the CDC 6400, and a two-processor version of the 6400 was called the CDC 6500. Cray turned to an even faster machine built along different lines, then known as the 6800.

A Fortran compiler known as MNF (Minnesota Fortran) was developed by Lawrence A. Liddiard and E. James Mundstock at the University of Minnesota for the 6600.^[2]

It was after the delivery of the 6600 that IBM took notice of this new company. At the time, Thomas J. Watson, Jr. asked (words to the effect of) How is it that this tiny company of 34 people — including the janitor — can be beating us when we have thousands of people?, to which Cray reportedly quipped You just answered your own question. In 1965, IBM started an effort to build its own machine that would be even faster than the 6600, the ACS-1. Two hundred people were gathered together on the U.S. West Coast to work on the project, away from corporate prodding, in an attempt to mirror Cray's off-site lab. The project produced interesting computer architecture and technology, but it was not compatible with IBM's very successful System/360 line of computers. The computer-makers were directed to make it IBM-360-compatible, but that compromised its performance. The ACS was canceled in 1969, no product was ever produced. Many of the engineers left the company, leading to a brain-drain in IBM's high-performance departments.

In the meantime, IBM announced a new version of the famed System/360, the Model 92, which would be just as fast as CDC's 6600. This machine did not exist, but its nonexistence did not stop sales of the 6600 from drying up, while people waited for the release of the mythical Model 92. Norris did not take this tactic, dubbed as fear, uncertainty and doubt (FUD), lying down, and in an extensive antitrust lawsuit launched against IBM a year later, he eventually won a settlement valued at $80 million.^[3] He picked up IBM's subsidiary Service Bureau Corporation (SBC), which ran computer processing for other corporations on its own computers. SBC fit nicely into CDC's existing service bureau offerings.^[4]

During the designing of the 6600, CDC had set up Project SPIN to supply the system with a high speed hard disk memory system. At the time, it was unclear if disks would replace magnetic memory drums, nor was it clear at the time whether fixed or removable disks would become the more prevalent. Thus, SPIN explored all of these approaches, and eventually it delivered a very large 28" diameter fixed disk and also a smaller multi-platter 14" removable disk-pack system. Over time, the hard disk business pioneered in SPIN would turn into a major product line.

CDC 7600 and 8600

In the same month it won its lawsuit against IBM, CDC also announced its new computer, the CDC 7600 (previously referred to as the 6800 within CDC). This machine's hardware clock speed was almost four times that of the 6600 (36 MHz vs. 10 MHz), and it offered considerably more than four times the total throughput. Much of this speed increase was due to extensive use of pipelining, a technique that allows different parts of the CPU to work simultaneously on different parts of successive instructions of the process at the same time (in the same way that an automotive assembly line can produce one vehicle every 90 seconds, and thus easily 300 vehicles per 8 hour shift by doing a partial assembly of each vehicle simultaneously every 90 seconds, while any one vehicle will take several hours to be completely assembled). With this technique, the time to run any particular instruction is no faster, but the program as a whole moves through the computer more quickly since the instructions are queued in an efficient manner.

The 7600 did not do well in the marketplace because it was introduced in the 1969 downturn in the U.S. national economy. Its complexity had led to poor reliability. The machine was slightly incompatible with the 6000-series, so it required a completely different operating system, which like most new OSs, was primitive. The 7600 project paid for itself, yet it damaged CDC's reputation.

Cray then turned to the design of the CDC 8600. This design included four processors in a single, smaller case. The smaller size and shorter signal paths allowed the 8600 to run at much higher clock speeds, and in combination with higher speed memory, these features provided most of the performance gains. The 8600, however, belonged to the "old school" in terms of its physical construction, and it used individual components soldered to circuit boards. The design was so compact that cooling and servicing the CPU modules proved effectively impossible. Because of too many hot-running solder joints in it that the machines did not work reliably, Cray recognized that a re-design was needed.

The STAR and the Cyber

In addition to the redesign of the 8600, CDC had another project called the CDC STAR-100 underway, led by Cray's former collaborator on the 6600/7600, Jim Thornton. Unlike the 8600's "four computers in one box" solution to the speed problem, the STAR was a new design using a unit that we know today as the vector processor. By highly pipelining math instructions with purpose-built instructions and hardware, math processing is dramatically improved in a machine that was otherwise slower than a 7600. Although the particular set of problems it would be best at solving was limited - in comparison to the general-purpose 7600, it was for solving exactly these problems that customers would buy CDC machines.

Since these two projects competed for limited funds during the late 1960s, Norris felt that the company could not support simultaneous development of the STAR and a complete redesign of the 8600. Therefore, Cray left CDC to form the Cray Research company in 1972. Norris remained, however, a staunch supporter of Cray, and he even invested money into Cray's new company. In 1974, CDC released the STAR, designated as the Cyber 203. It turned out to have "real world" performance that was considerably worse than expected. STAR's chief designer, Jim Thornton, then left CDC to form the Network Systems Corporation.

A variety of systems based on the basic 6600/7600 architecture were repackaged in different price/performance categories of the CDC Cyber, which became CDC's main product line in the 1970s. An updated version of the STAR architecture, the Cyber 205, had considerably better performance than the original. By this time, however, Cray's own designs, like the Cray-1, were using the same basic design techniques as the STAR, but were computing much faster.

Sales of the STAR were weak, but Control Data Corp. produced a successor system, the Cyber 200/205, that gave Cray Research some competition. CDC also embarked on a number of special projects for its clients, who produced an even smaller number of black project computers. The CDC Advanced Flexible Processor (AFP), also known as CYBER PLUS, was one such machine.

Another design direction was the "Cyber 80" project, which was aimed at release in 1980. This machine could run old 6600-style programs, and also had a completely new 64-bit architecture. The concept behind Cyber 80 was that current 6000-series users would migrate to these machines with relative ease. The design and debugging of these machines went on past 1980, and the machines were eventually released under other names.

CDC was also attempting to diversify its revenue from hardware into services and this included its promotion of the PLATO (computer system) computer-aided learning system, which ran on Cyber hardware and incorporated many early computer interface innovations including bit-mapped touchscreen terminals.

ETA Systems, hard disks, oblivion

CDC decided to fight for the high-performance niche, but Norris recognized that the company had become moribund in his opinion and unable to quickly design competitive machines. So in 1983, he set up a spinoff company, ETA Systems, whose design goal being a machine processing data at 10 GFLOPs, about 40 times the speed of the Cray-1. The design never fully matured, and it was unable to reach its goals. Nevertheless, the product was one of the fastest computers on the market, and a handful of those computers were sold during the next few years. The effort ended after half-hearted attempts to sell ETA Systems. In 1989, most of the employees of ETA Systems were laid off, and the remaining ones were folded into CDC.

Meanwhile, several very large Japanese manufacturing firms were entering the market. The supercomputer market was too small to be able to afford more than a handful of companies, so CDC started looking for other markets. One of these was the high-performance hard disk drive market, which was becoming more lucrative as personal computers (PCs) began to include them in the mid-1980s. Through its Magnetic Peripherals unit, originally a joint venture with Honeywell and Honeywell Bull, CDC became a major player in the hard disk drive market. It was the world wide leader in 14 inch disk drive technology in the OEM marketplace in the 1970s and early 1980s especially with its SMD (Storage Module Drive) and CMD (Cartridge Module Drive). CDC was an early developer of the eight-inch drive technology that was pioneered by Shugart Associates with products from its MPI Oklahoma City Operation. Its CDC Wren series drives were particularly popular with "high end" users, although it was behind the capacity growth and performance curves of numerous startups such a Micropolis, Atasi, Maxtor, and Quantum. CDC also co-developed the now universal Advanced Technology Attachment (ATA) interface with Compaq and Western Digital, which was aimed at lowering the cost of adding low-performance drives.

Inexplicably, CDC exited the hard disk drive business entirely in 1988, spinning off Magnetic Peripherals under the name Imprimis. The next year, Seagate Technology, which had been seriously lagging in the high-end drive market, purchased Imprimis. The remainder of CDC was renamed Control Data Systems, Inc. and was bought out by Syntegra (USA), a subsidiary of the BT Group, and merged into BT's Global Services organization.

CDC's Energy Management Division was one of the most successful CDC business units, providing control systems solutions that managed as much as 25% of all electricity on the planet. In 1988 or 1989 this division was renamed Empros and was later sold to Siemens as CDC broke apart.

CDC's services business was spun off in 1992, and it became known as the Ceridian Corporation. Ceridian continues as a successful outsourced IT company focusing on human resources. In 1997 General Dynamics acquired the Computing Devices International Division of Ceridian. Computing Devices, headquartered in Bloomington, Minnesota, was a defense electronics and systems integration business, originally Control Data's Government Systems Division.

Commercial Credit Corporation

In 1986, Sandy Weill convinced the Control Data management to spin off their Commercial Credit subsidiary. Over a period of years Weill used Commercial Credit to build an empire that became Citigroup.^{[citation needed]} In 1968, Commercial Credit Corporation was the target of a hostile takeover by Loews Inc. Loews had acquired nearly 10% of CCC, which it intended to break up on acquisition. To avoid the takeover CCC forged a deal with CDC lending them the money to purchase control in CCC instead, and "That is how a computer company came to own a fleet of fishing boats in the Chesapeake Bay."^[5]

Timeline of CDC systems releases

• 1957 — Founding
• 1959 — 1604
• 1960 — 1604-B
• 1961 — 160
• 1962 — 924
• 1963 — 160A, 1604-A, 3400, 6600
• 1964 — 160-G, 3100, 3200, 3600, 6400
• 1965 — 1604-C, 1700, 3300, 3500, 8050, 8090
• 1966 — 3800, 6200, 6500, STATION 6000
• 1968 — 7600
• 1969 — 6700
• 1970 — STAR-100
• 1971 — CYBER 71, CYBER 72, CYBER 73, CYBER 74, CYBER 76
• 1972 — 5600, 8600
• 1973 — CYBER 170, CYBER 172, CYBER 173, CYBER 174, CYBER 175, SYSTEM 17
• 1976 — CYBER 18
• 1977 — CYBER 171, CYBER 176, OMEGA/480
• 1979 — CYBER 203, CYBER 720, CYBER 730, CYBER 740, CYBER 750, CYBER 760
• 1980 — CYBER 205
• 1982 — CYBER 815, CYBER 825, CYBER 835, CYBER 845, CYBER 855, CYBER 865, CYBER 875
• 1983 — ETA10
• 1984 — CYBER 810, CYBER 830, CYBER 840, CYBER 850, CYBER 860, CYBER 990, CYBERPLUS
• 1987 — CYBER 910, CYBER 930, CYBER 995
• 1988 — CYBER 960
• 1989 — CYBER 920, CYBER 2000

Film and science fiction references

• The pilot episode of The Six Million Dollar Man, "The Moon and the Desert", featured computers in the O.S.I. laboratory, emblasoned with the CDC "Control Data" badge.
• Colossus: The Forbin Project — The title sequences to this film include tape drives and other early CDC equipment.
• The Thief Who Came to Dinner, 1973 by Terrence Lore Smith and Walter Hill — Ryan O'Neal plays a bored Control Data employee who decides to retire and turn to a life of crime, but breaks back in to use the computers to help him in a game of chess with the detective who is on his trail.
• The Adolescence of P-1, by Thomas Ryan — Control Data computers were very enticing to young P-1.
• Tron — In the wide screen version of the film, when Flynn and Lora sneak into Encom, a CDC 7600 is visible in the background, alongside a Cray-1. This scene was shot at the Lawrence Livermore National Laboratory.
• Die Hard — The computer room shot up by one of the terrorists contained a number of working Cyber 180 computers and a mock-up of an ETA-10 supercomputer, along with a number of other peripheral devices, all provided by CDC Demonstration Services/Benchmark Lab. This equipment was requested on short notice after another computer manufacturer backed out at the last minute. Paul Derby, manager of the Benchmark Lab, arranged to send two van-loads of equipment to Hollywood for the shoot, accompanied by Jerry Stearns of the Benchmark Lab who watched over this equipment. After the machines were returned to Minnesota, they were inspected and tested, and as each machine was sold, a notation was made in the corporate records that the machine had appeared in the film.
• The New Avengers — In episode #23 ("Complex") Purdey uses a CDC card reader.
• They Live, by John Carpenter — As Roddy Piper is trying on his new "sunglasses" that allow him to see the world as it is, he looks at an advertisement for Control Data Corporation and sees the word OBEY. The film's credits include "special thanks" to CDC.
• Mi-Sex — Computer Games: 1979 pop music video. The band enters the computer room in the Control Data North Sydney building and proceeds to play with CDC equipment.

Notes

1. ^ Curiously, a very detailed 1975 oral history with CDC's computer engineers does not confirm this legend: when the "1604" question was asked, the insiders laughed and responded: "It was quite popular at the time that this was the origin." Page 21 of the oral history provides the official CDC explanation for 1604.
2. ^ Frisch, Michael (Dec 1972). "Remarks on Algorithms". Communications of the ACM 15 (12): 1074. 
3. ^ Oral history interview with Richard G. Lareau, Charles Babbage Institute, University of Minnesota.
4. ^ "COMPUTERS: A Settlement for IBM", Time magazine, Monday, Jan. 29, 1973.

   "In return for dropping its suit, Control Data won a good deal. For about $16 million, it will acquire IBM's Service Bureau Corp., a subsidiary that processes customers' data and sells time on its own computers. Wall Street analysts reckon that the Service Bureau's real market value is closer to $60 million. In addition, IBM will buy services from the bureau for five years, stay out of the services business itself in the U.S. for six years and reimburse Control Data for $15 million in legal fees spent on the case. Total cost of the package to IBM: at least $80 million. William C. Norris, Control Data's one-man-gang chairman, said that the daring suit had turned out to be 'one of the best management decisions in our history.' ..."

5. ^ Price, Robert (2005-11-11). The Eye for Innovation: Recognizing Possibilities and Managing the Creative Enterprise. 11 (1 ed.). New Haven, Ct: Yale University Press. pp. 168. ISBN 978-0300108774. http://yalepress.yale.edu/yupbooks/book.asp?isbn=0300123701. 

References

• Lundstrom, David. A Few Good Men from Univac. Cambridge, Massachusetts: MIT Press, 1987. ISBN 0262121204.
• Murray, Charles, and John Wiley. The Supermen: The Story of Seymour Cray and the Technical Wizards behind the Supercomputer. New York: John Wiley, 1997. ISBN 0471048852.
• Worthy, James C. William C. Norris: Portrait of a Maverick. Ballinger Pub Co., May 1987. ISBN 978-0887300875

External links

• Control Data Corporation Records at the Charles Babbage Institute, University of Minnesota, Minneapolis; CDC records donated by Ceridian Corporation in 1991; finding guide contains historical timeline, product timeline, and acquisitions list.
• Oral history interview with William Norris discusses ERA years, acquisition of ERA by Remington Rand, the Univac File computer, work as head of the Univac Division, and the formation of CDC. Charles Babbage Institute, University of Minnesota, Minneapolis.
• Oral history interview with Willis K. Drake Discusses Remington-Rand, the Eckert-Mauchly Computer Company, ERA, and formation of Control Data Corporation. Charles Babbage Institute, University of Minnesota, Minneapolis.
• Oral history with Richard D. Conner Charles Babbage Institute, University of Minnesota, Minneapolis. Conner discusses CDC's social programs and employee assistance programs.
• Two early oral history interviews with Robert Price Charles Babbage Institute, University of Minnesota, Minneapolis.
• Oral history interview with Eugene L. Baker Charles Babbage Institute, University of Minnesota, Minneapolis. Baker discusses CDC's social and employee programs.
• Oral history interview with Norbert R. Berg Charles Babbage Institute, University of Minnesota. Berg discusses the development of CDC's employee assistance programs.
• Oral history interview with Mike Schumacher discusses the development of operating and applications software for the CDC 1604 and later Control Data Corporation computers. Charles Babbage Institute, University of Minnesota, Minneapolis.
• Oral history interview with Charles F. Crichton discusses the history of data services at Control Data Corporation. Charles Babbage Institute, University of Minnesota, Minneapolis.
• Organized discussion moderated by Neil R. Lincoln with eighteen Control Data Corporation (CDC) engineers on computer architecture and design. Charles Babbage Institute, University of Minnesota, Minneapolis. Engineers include Robert Moe, Wayne Specker, Dennis Grinna, Tom Rowan, Maurice Hutson, Curt Alexander, Don Pagelkopf, Maris Bergmanis, Dolan Toth, Chuck Hawley, Larry Krueger, Mike Pavlov, Dave Resnick, Howard Krohn, Bill Bhend, Kent Steiner, Raymon Kort, and Neil R. Lincoln. Discussion topics include CDC 1604, CDC 6600, CDC 7600, CDC 8600, CDC STAR-100 and Seymour Cray.
• Information about the spin out of Commercial Credit from Control Data by Sandy Weill
• Information about the Control Data CDC 3800 Computer—on display at the National Air and Space Museum Steven F. Udvar-Hazy Center near Washington Dulles International Airport.
• Private Collection of historical documents about CDC
• Control Data User Manuals Library @ Computing History
• Computing history describing the use of a range of CDC systems and equipment 1970-1985
• A German collection of CDC, Cray and other large computer systems, some of them in operation