Scientific Data Systems
| File:Scientific Data Systems logo.svg Company logo used throughout much of the 1970s | |
| Industry | Computers |
|---|---|
| Founded | 1961 in Santa Monica, California |
| Founders |
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| Defunct |
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| Successor | Xerox Data Systems |
Scientific Data Systems (SDS) was a United States-based computer company established in September 1961 by Max Palevsky, Arthur Rock, Robert Beck, and a team of eleven computer scientists. SDS was among the first to implement silicon transistor technology and early integrated circuit integration within their computer architectures. Targeting scientific computing applications, SDS secured numerous contracts with NASA during the Space Race. Their offerings were distinguished by combining high performance with competitive pricing. After being acquired by Xerox in 1969, the company faced decreased sales during the oil crisis of 1973–74, leading to its shutdown in 1975. Operating under Xerox as Xerox Data Systems (XDS), it developed the Xerox 500 series.
Initial products
In the 1960s, SDS entered a marketplace largely controlled by IBM and competitors such as Burroughs Corporation, UNIVAC, and Control Data Corporation. SDS expanded its market presence by introducing time-sharing systems built with silicon transistor technology, including the 24-bit SDS 910 and SDS 920, which featured hardware integer multipliers. These models were among the earliest commercial computers to utilize silicon transistors, enhancing reliability while reducing costs.
The company provided bundled software, notably a FORTRAN compiler created by Digitek, which took advantage of their Programmed OPeratorS (POPS) hardware mechanism. This innovation allowed for efficient single-pass compilation within constrained memory environments (4K 24-bit words) without requiring secondary storage, thereby accelerating scientific programming efforts.
In June 1963, SDS released the SDS 9300, incorporating a floating point unit and expanding memory capacity from 16 to 32 kWords. It achieved nearly ten times faster integer addition compared to earlier models but lacked backward compatibility with previous instruction sets.
Later that year, in December 1963, SDS introduced the integrated circuit-based SDS 930, a more affordable redesign of the 9xx series priced at approximately $105,000. Although it generally operated slower than the SDS 9300 due to reduced hardware features, it provided an economical option for scientific users. Smaller variants included the 12-bit SDS 92 and the IC-equipped SDS 925.
The University of California, Berkeley’s Project Genie contributed segmentation and relocation capabilities for time-sharing on the SDS 930 platform, which were commercialized in the SDS 940. This model added hardware support for memory management and interruptible instructions, becoming pivotal for Tymshare’s expansion of circuit-switched networks during the late 1960s. In 1968, a modified version named the SDS 945 was announced with decreased I/O capabilities but comparable computational power; however, its commercial availability remains uncertain.
SDS 92
The SDS 92, launched in 1965, is acknowledged as the first commercially available computer to employ monolithic integrated circuits. It incorporated approximately fifty IC-based circuit cards, representing a major advancement in computer hardware design.
This general-purpose system featured a 12-bit architecture aimed at providing a compact, rapid, and cost-effective computing solution. It was incompatible with other SDS product lines such as the 900 series or the Sigma series. Key technical aspects included:
- Instructions of both 12- and 24-bit lengths
- A 12-bit word size with an added parity bit
- Core memory starting at 2048 words with a cycle time of 1.75 microseconds, expandable up to 32,768 words—all directly addressable
Standard peripherals compatible with the SDS 92 encompassed:
- Keyboard/printer (teletype) operating at ten characters per second, optionally supplemented by paper tape reader and punch devices
- Paper tape reader functioning at 300 characters per second
- Paper tape punch running at sixty characters per second
- The MAGPAK Magnetic Tape System
By integrating IC technology alongside an economical design approach, the SDS 92 secured a competitive position within the mid-1960s computer marketplace.
Sigma series
In December 1966, SDS introduced the Sigma series, initially featuring the 16-bit Sigma 2 and the 32-bit Sigma 7 models, which shared a common internal architecture. As a response to the success of IBM's System/360 and the industry-wide adoption of 8-bit ASCII standards, SDS developed an alternative system that utilized comparable data formats but implemented the EBCDIC character encoding. The Sigma series was architected with multiple processor registers instead of relying on a single accumulator, aligning it closely with many of the System/360's technical specifications.
This product line later grew to include models such as the Sigma 5 and Sigma 6, while Xerox’s Sigma 9 incorporated advanced capabilities like instruction lookahead. Entry-level systems like the Sigma 8 and the Sigma 9 mod 3 served as upgrade options for earlier models. European licensee CII marketed approximately 60 units of the Sigma 7 and engineered the Iris 80, which featured virtual memory and dual-processor functionality; they also produced around 160 units of the Sigma 2.
The Sigma series was particularly effective for real-time computing applications due to its advanced hardware interrupt architecture and dedicated I/O processor. A notable milestone was that the first ARPANET node at UCLA operated on an SDS Sigma 7 machine.
Xerox models
Although Xerox acquired SDS in 1969, this did not translate into substantial market share growth; SDS maintained roughly a 1% share of U.S. computer sales. At the time of acquisition, about 1,000 SDS systems were operational; by the division’s closure in 1975, this number had increased modestly to approximately 2,100 units. Xerox introduced new models such as the redesigned Sigma-based 550 and 560, which experienced backlogs but had limited market penetration. Most of SDS’s rights were transferred to Honeywell in July 1975, which briefly continued manufacturing and support into the early 1980s.
Several competitors attempted to replace the Sigma 9 platform. The Telefile T-85 became a notable design success, although exact sales data is unavailable. Other contenders like Modutest Mod 9, Ilene Model 9000, and Real-time RCE-9 were developed but likely remained at prototype stages without significant commercial release.
A new start
In 1979, former SDS personnel reestablished the company with investment from Max Palevsky, Sanford Kaplan, Dan McGurk, among others. Engineers including Jack Mitchell, William L. Scheding, and Henry Harold introduced the SDS-420—a microprocessor-based system powered by a 6502A CPU with up to 56 KB of memory running on their proprietary OS named SDS-DOS, which incorporated Microsoft’s BASIC language. The SDS-420 featured dual single-sided double-density floppy drives (400 KB per side) supplied by PerSci of California. Its successor, the SDS-422 Model, upgraded storage with dual double-sided double-density floppy drives. Additional hardware options comprised a 6551-A USART and a proprietary network system called SDS-NET that utilized a Zilog Z8530 chip alongside software inspired by early Xerox Ethernet technology.
Approximately 1,000 units were sold worldwide across locations including Tahiti, London, Italy, New York City, and Los Angeles. The focus of the 400 Series was on word processing and business applications rather than scientific computing.
At COMDEX in the early 1980s, SDS presented SDS-NET—a LAN-based file server derived from the Model 430 and developed by Sam Keys. The SDS-430 Server enabled file and printer sharing over SDS-NET or modem connections using a Micropolis hard disk with a capacity of 10 MB. Other offerings included the diskless workstation model SDS-410 that booted via SDS-NET or through a 1200 bit/s modem link.
Key software products encompassed Word (a word processing application created by John McCully, formerly of Jacquard Systems) and an extensive accounting suite covering General Ledger, Accounts Receivable, Accounts Payable, and Payroll modules developed by Tom Davies and Sandra Mass from Jacquard Systems. Additional software included Legal Time and Billing, Medical Time and Billing solutions, and TTY terminal emulation utilizing the 6551 USART.
Through partnerships with value-added resellers (VARs), SDS broadened its software range to include systems for solid-waste management with automated routing for trucks as well as accounting packages tailored for country clubs. A prominent UK VAR was Jacq-Rite based in Surrey; they specialized in vertical market software for insurance sectors. Acting on John McCully’s recommendation, Jacq-Rite transitioned from Jacquard hardware to the SDS 400 series and installed networks within Lloyd’s Managing Agents and Members Agencies during 1982–83. Justin Hill contributed as one of Jacq-Rite’s programmers porting software while David Ensor handled hardware sales operations.
SDS in the United Kingdom
In 1983, Ensor and Hill departed from Jacq-Rite to establish Scientific Data Systems UK Limited (SDS UK) based in Crawley, West Sussex. Their objective was to develop a business centered on SDS's 4000 series computers under an exclusive agreement. The 4000 series represented a revamped design that preserved the architecture and software compatibility of the 400 series, incorporating new hardware components such as Seagate hard drives with 10 and 20 MB capacities, a SCSI interface, and a detachable keyboard finished in beige.
Nonetheless, SDS encountered serious financial difficulties, resulting in SDS UK receiving only a limited number of units. To address this challenge, Hill reverse-engineered the 4000 by utilizing schematics sourced from SDS, producing an unofficial clone with enhancements in board layout and connectivity. Mitchell from SDS provided remote assistance to finalize firmware development. A prototyping company located in Poole, Dorset manufactured several units, including a network of five stations sold to the Institute of Legal Executives in Bedford; this setup was supported by customized software created by Hill and Paula Flint.
Despite these initiatives, SDS UK's market opportunities declined as Jacq-Rite transitioned to the IBM PC platform, taking its client base along. Hill further upgraded the computer with an external hard drive enclosure that utilized SCSI technology to accommodate larger capacity drives. However, constrained financial resources limited both manufacturing quality and product innovation. Additionally, the machines were priced higher than IBM’s emerging PC/AT models, which negatively impacted their market competitiveness.
By 1984, with ties between SDS US and SDS UK severed and lacking development funding, both entities ceased their operations.
Computer models
| 24-bit systems | SDS 910 SDS 920 SDS 9300 SDS 925 SDS 930 SDS 940 |
launched initially with the 920 in August 1962 enhanced 920 featuring FPU and expanded memory (1963) a faster and more affordable version of the 920 (1964) significant redesign introduced (1963) 930 model incorporating time-sharing capabilities (1966) |
| 12-bit system | SDS 92 | entry-level model released in 1965 |
| 16-bit systems | SDS Sigma 2 SDS Sigma 3 CE16 & CF16 |
(1966) (1969) 1969 |
| 32-bit systems | SDS Sigma 5 SDS Sigma 6/7 Xerox Sigma 8/9 |
(1967) (1966) (1971) |
Known users
Originally designed for scientific applications, the SDS 900 and Sigma lines gained widespread adoption in commercial time-sharing environments. A key customer, Comshare Inc., headquartered in Ann Arbor, Michigan, advanced the hardware throughout the 1980s and continued operating Sigma 9 systems commercially until approximately 1993. Comshare introduced innovations such as the I-Channel interface enabling IBM-compatible Bus/Tag devices and the ISI Communications interface that facilitated connectivity with contemporary storage solutions and software like Commander II. Following Xerox’s exit from mainframe production and asset transfer to Honeywell, Comshare established a research facility in Phoenix where three Sigma 9 machines were assembled using remanufactured components.
During the 1960s, Recognition Equipment Inc. employed SDS 910 computers for optical character recognition technology.
Additional prominent U.S. users included:
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Internationally recognized users encompassed:
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SDS software
Monarch served as the chief operating system for the 900 series. For the Sigma line of 32-bit machines, users had access to RBM, a combined real-time and batch monitor, as well as BTM, which supported batch processing and timesharing. In 1971, the introduction of the more sophisticated timesharing system UTS marked a significant advancement; this system was later enhanced into what became known as CP-V. RBM eventually gave way to CP-R, which offered both real-time and timesharing capabilities. By March 1982, Honeywell handed over the remaining software rights for the 900 series to a group based in Kansas City to continue maintenance and support, since Honeywell had discontinued its own support several years prior. In September 2006, this entire software collection along with its documentation was donated to the Computer History Museum, constituting one of the most comprehensive preserved archives of 1960s software. Unfortunately, timesharing software specific to the 940 series was not retained; additionally, customized versions employed by major clients such as Tymshare have also been lost.
Multiple simulators for the Sigma series are currently available, and the Computer History Museum actively acquires related software materials. Early editions of CP-V (notably C00 and earlier) were not copyrighted; however, subsequent versions developed by Honeywell (such as E00 and F00) were protected under copyright law. Certain CP-V D00 copies were distributed without licenses, leading some users to assert that these versions belonged in the public domain.
CE16 and CF16
Xerox unveiled its CE16 and CF16 minicomputers in May 1969, aiming these models at process control applications. Both machines came equipped with a standard 4 KW of 16-bit core memory expandable up to 16 KW and included three interrupt channels. The CE16’s CPU executed addition operations in 16 microseconds and performed multiplication via software in 126 microseconds; it was priced at $12,800 in 1969. The CF16 offered enhanced performance with addition completed in 5.33 microseconds and hardware-based multiplication achieved in 42 microseconds, carrying a price tag of $14,900. These products exemplified Xerox’s strategic emphasis on specialized industrial computing within their broader corporate portfolio.
See also
Further reading
- "Enter Max Palevsky", Time Magazine, February 24, 1967
External links
- Oral history interview with Paul A. Strassmann, Charles Babbage Institute, University of Minnesota
- Scientific Data Systems The Sigma Family brochure, 1967
- SDS Sigma 7 technical information
- SDS 900 series documentation at bitsavers.org
- Sigma series documentation at bitsavers.org
- Tymshare documentation at bitsavers.org
- Pages with broken file links
- Scientific Data Systems
- American companies established in 1961
- American companies disestablished in 1984
- Computer companies established in 1961
- Computer companies disestablished in 1984
- Defunct computer companies of the United States
- Defunct computer hardware companies
- Defunct computer systems companies
- Companies of the United States by year of establishment
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