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Scientific Data Systems

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</style><table class="infobox ib-company vcard"><caption class="infobox-title fn org" style="font-size: 125%;">Scientific Data Systems</caption><tbody><tr><td colspan="2" class="infobox-image ib-company-logo logo"><div class="infobox-caption">Logo of the company during most of the 1970s</div></td></tr><tr><th scope="row" class="infobox-label">Industry</th><td class="infobox-data category">Computers</td></tr><tr><th scope="row" class="infobox-label">Founded</th><td class="infobox-data">1961 (1961) in <a href="Santa_Monica%2C_California" title="Santa Monica, California">Santa Monica, California</a></td></tr><tr><th scope="row" class="infobox-label">Founders</th><td class="infobox-data agent"><style data-mw-deduplicate="TemplateStyles:r1126788409">

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</style><div class="plainlist"><ul><li><a href="Max_Palevsky" title="Max Palevsky">Max Palevsky</a></li><li>Robert Beck</li></ul></div></td></tr><tr><th scope="row" class="infobox-label">Defunct</th><td class="infobox-data"><div class="plainlist"><ul><li>1975</li><li>1984 (1984) (UK division)</li></ul></div></td></tr><tr><th scope="row" class="infobox-label">Successor</th><td class="infobox-data">Xerox Data Systems</td></tr></tbody></table>

Scientific Data Systems (SDS), was an American <a href="Computer_company" class="mw-redirect" title="Computer company">computer company</a> founded in September 1961 by <a href="Max_Palevsky" title="Max Palevsky">Max Palevsky</a>, <a href="Arthur_Rock" title="Arthur Rock">Arthur Rock</a> and Robert Beck, veterans of <a href="Packard_Bell_Corporation" title="Packard Bell Corporation">Packard Bell Corporation</a> and <a href="Bendix_Corporation" title="Bendix Corporation">Bendix</a>, along with eleven other computer scientists. SDS was the first to employ <a href="Silicon_transistor" class="mw-redirect" title="Silicon transistor">silicon transistors</a>, and was an early adopter of <a href="Integrated_circuit" title="Integrated circuit">integrated circuits</a> in computer design. The company concentrated on larger scientific workload focused machines and sold many machines to <a href="NASA" title="NASA">NASA</a> during the <a href="Space_Race" title="Space Race">Space Race</a>. Most machines were both fast and relatively low-priced. The company was sold to <a href="Xerox" title="Xerox">Xerox</a> in 1969, but dwindling sales due to the <a href="Oil_crisis_of_1973%E2%80%9374" class="mw-redirect" title="Oil crisis of 1973–74">oil crisis of 1973–74</a> caused Xerox to close the division in 1975 at a loss of hundreds of millions of dollars. During the Xerox years the company was officially Xerox Data Systems (XDS), whose machines were the <a href="Xerox_500_series" title="Xerox 500 series">Xerox 500 series</a>.

<div class="mw-heading mw-heading2"><h2 id="History">History</h2></div>

<div class="mw-heading mw-heading3"><h3 id="Early_machines">Early machines</h3></div>

Throughout the majority of the 1960s the US computer market was dominated by "Snow White", <a href="IBM" title="IBM">IBM</a>, and the "Seven Dwarves", <a href="Burroughs_Corporation" title="Burroughs Corporation">Burroughs</a>,

<a href="UNIVAC" title="UNIVAC">UNIVAC</a>, <a href="NCR_Corporation" class="mw-redirect" title="NCR Corporation">NCR</a>, <a href="Control_Data_Corporation" title="Control Data Corporation">Control Data Corporation</a>, <a href="Honeywell" title="Honeywell">Honeywell</a>, <a href="General_Electric" title="General Electric">General Electric</a>, and <a href="RCA" title="RCA">RCA</a>. SDS entered this well-developed market and was able to introduce a <a href="Time-sharing" title="Time-sharing">time-sharing</a> computer at just the right time. Much of their success was due to the use of <a href="Silicon" title="Silicon">silicon</a>-based <a href="Transistor" title="Transistor">transistors</a> in their earliest designs, the <a href="24-bit" class="mw-redirect" title="24-bit">24-bit</a> <a href="SDS_910" class="mw-redirect" title="SDS 910">SDS 910</a> and <a href="SDS_920" class="mw-redirect" title="SDS 920">SDS 920</a> which included a hardware (integer) multiplier. These are arguably the first commercial systems based on silicon,<a href="#cite_note-1">[1]</a> rather than <a href="Germanium" title="Germanium">germanium</a>, which offered much better reliability for no real additional cost.<a href="#cite_note-2">[2]</a>

Additionally, the SDS machines shipped with a selection of software, notably a <a href="FORTRAN" class="mw-redirect" title="FORTRAN">FORTRAN</a> <a href="Compiler" title="Compiler">compiler</a>, developed by <a href="Digitek" title="Digitek">Digitek</a>, that made use of the systems' Programmed OPeratorS (POPS),<a href="#cite_note-3">[3]</a><a href="#cite_note-4">[4]</a> and could compile, in 4K 24-bit words, programs in a single pass without the need for <a href="Magnetic_tape" title="Magnetic tape">magnetic tape</a> secondary storage. For scientific users writing small programs, this was a real boon and dramatically improved development turnaround time.

The 910 and 920 were joined by the <a href="SDS_9300" class="mw-redirect" title="SDS 9300">SDS 9300</a>, announced in June 1963. Among other changes, the 9300 included a <a href="Floating_point_unit" class="mw-redirect" title="Floating point unit">floating point processor</a> for higher performance. The performance increase was dramatic; the 910/920 needed 16 <a href="Microsecond" title="Microsecond">microseconds</a> to add two 24-bit <a href="Integer" title="Integer">integers</a>, the 9300 only 1.75, almost 10 times as fast. The 9300 also increased maximum memory from 16 <a href="Kiloword" class="mw-redirect" title="Kiloword">kWords</a> to 32 kWords. Although its instruction format resembled that of the earlier machines, it was not compatible with them.

In December 1963 SDS announced the <a href="SDS_930" title="SDS 930">SDS 930</a>, a major re-build of the 9xx line using integrated circuits (ICs) in the central processor. It was comparable to the 9300 in basic operations, but was generally slower overall due to the lack of the 9300's memory interlace capability and hardware floating point unit (although a hardware floating point "correlation and filtering unit" was available as an expensive option). The 930 cost less than half that of the original 9300, at about $105,000 (equivalent to $1,078,000 in 2024). Cut-down versions of the 920 also followed, including the 12-bit <a href="SDS_92" class="mw-redirect" title="SDS 92">SDS 92</a>, and the IC-based 925.

<a href="Project_Genie" title="Project Genie">Project Genie</a> developed a segmentation and relocation system for <a href="Time-sharing" title="Time-sharing">time-sharing</a> use on the 930 at the <a href="University_of_California%2C_Berkeley" title="University of California, Berkeley">University of California, Berkeley</a>, which was commercialized in the <a href="SDS_940" title="SDS 940">SDS 940</a>. It had additional hardware for relocation and swapping of memory sections, and interruptible instructions. The 940 would go on to be a major part of <a href="Tymshare" title="Tymshare">Tymshare</a>'s <a href="Circuit-switched" class="mw-redirect" title="Circuit-switched">circuit-switched</a> network system growth in the 1960s (pre-ARPAnet and before packet-switching). A 945 was announced in July 1968 as a modified 940 with less <a href="Input/output" title="Input/output">I/O</a> and the same compute power, but it is unclear whether this shipped.<a href="#cite_note-Calkins-5">[5]</a>

The SDS 92<a href="#cite_note-SDS92Ref-6">[6]</a> is generally accepted as the first commercial computer using monolithic integrated circuits.<a href="#cite_note-7">[7]</a><a href="#cite_note-8">[8]</a> ICs were used on about 50 circuit cards.<a href="#cite_note-Calkins-5">[5]</a>

The SDS 92 is a small, high-speed, very low-cost, general purpose computer 12-bit system introduced in 1965.<a href="#cite_note-SDS92Ref-6">[6]</a><a href="#cite_note-9">[9]</a> it was not compatible with other SDS lines such as the 900 series or the <a href="SDS_Sigma_series" title="SDS Sigma series">Sigma series</a>.<a href="#cite_note-10">[10]</a> Features included:<a href="#cite_note-SDS92Ref-6">[6]</a>

<ul><li>12- and 24-bit instructions</li>

<li>12-bit word plus parity bit</li>

<li>2048-word basic memory (1.75 <a href="Microsecond" title="Microsecond">μsec</a> memory cycle) expandable to 4096, 8192, 16,384 or 32,768 words, all directly addressable</li></ul>

Peripheral equipment available from SDS standard peripheral line included:<a href="#cite_note-SDS92Ref-6">[6]</a>

<ul><li>10 <a href="Characters_per_second" class="mw-redirect" title="Characters per second">cps</a> (characters per second) Keyboard/printer (<a href="Teletype" class="mw-redirect" title="Teletype">teletype</a>) with or without paper tape reader and punch</li>

<li>300 cps paper tape reader</li>

<li>60 cps paper tape punch</li>

<li><a href="SDS_9_Series#MAGPAK" title="SDS 9 Series">MAGPAK</a> Magnetic Tape System</li></ul>

<div class="mw-heading mw-heading3"><h3 id="Sigma_series">Sigma series</h3></div>

In December 1966 SDS shipped the entirely new <a href="SDS_Sigma_series" title="SDS Sigma series">Sigma series</a>, starting with the <a href="16-bit" class="mw-redirect" title="16-bit">16-bit</a> Sigma 2 and the <a href="32-bit" class="mw-redirect" title="32-bit">32-bit</a> Sigma 7, both using common hardware internally. The success of the <a href="IBM_System/360" title="IBM System/360">IBM System/360</a> and the rise of the 7-bit <a href="ASCII" title="ASCII">ASCII</a> character standard was pushing all vendors to the 8-bit standard from their earlier 6-bit ones. SDS was one of the first companies to offer a machine intended as an alternative to the IBM System/360; although not compatible with the 360, it used similar data formats, the EBCDIC character code, and in other ways, such as its use of multiple <a href="Processor_register" title="Processor register">registers</a> rather than an <a href="Accumulator_(computing)" title="Accumulator (computing)">accumulator</a>, it was designed to have specifications that were comparable to those of the 360.

Various versions of the Sigma 7 followed, including the cut-down Sigma 5 and re-designed Sigma 6. The Xerox Sigma 9 was a major re-design with instruction lookahead and other advanced features, while the Sigma 8 and Sigma 9 mod 3 were low-end machines offered as a migration path for the Sigma 5. The French company <a href="Groupe_Bull" title="Groupe Bull">CII</a>, as a licensee of SDS, sold about 60 Sigma 7 machines in Europe, and developed an upgrade with <a href="Virtual_memory" title="Virtual memory">virtual memory</a> and <a href="Multiprocessing" title="Multiprocessing">dual-processor</a> capability, the <a href="Iris_80" class="mw-redirect" title="Iris 80">Iris 80</a>. CII also manufactured and sold some 160 Sigma 2 systems.

The Sigma range was very successful in the niche real-time processing field, due to the sophisticated <a href="Hardware_interrupt" class="mw-redirect" title="Hardware interrupt">hardware interrupt</a> structure and independent I/O processor. The first node of <a href="ARPANET" title="ARPANET">ARPANET</a> was established by <a href="Leonard_Kleinrock" title="Leonard Kleinrock">Leonard Kleinrock</a> at <a href="UCLA" class="mw-redirect" title="UCLA">UCLA</a> with an SDS Sigma 7 system.

<div class="mw-heading mw-heading3"><h3 id="Xerox_models">Xerox models</h3></div>

Even with these successes, when Xerox bought the company in 1969 they sold only about 1% of the computers in the <a href="United_States" title="United States">United States</a>, something Xerox never seemed to improve. When they were purchased, about 1,000 SDS machines of all types were in the market, and by the time the division closed in 1975 this had increased to only about 2,100. By this point, the newer Xerox 550 and 560 models, extensively re-designed Sigmas, were about to come to market and were extensively back-ordered. Most rights were sold to <a href="Honeywell" title="Honeywell">Honeywell</a> in July 1975 who produced Sigmas for a short period, and provided support into the 1980s.

Several manufacturers attempted to enter the Sigma 9 replacement market. The first successful design was the Telefile T-85, but it is not clear how many were sold.<a href="#cite_note-11">[11]</a><a href="#cite_note-12">[12]</a> Other efforts, including the Modutest Mod 9, Ilene Model 9000 and Real-time RCE-9 were designed, but it is not clear if they were ever produced past the prototype stage.<a href="#cite_note-13">[13]</a>

<div class="mw-heading mw-heading2"><h2 id="A_new_start">A new start</h2></div>

Former SDS employees restarted the company with funding from Max Palevsky, Sanford Kaplan, Dan McGurk, and others in 1979. Jack Mitchell, William L. Scheding, and Henry Harold, along with some other former SDS engineers introduced a microprocessor-based computer called the SDS-420<a href="#cite_note-14">[14]</a> built on a <a href="MOS_Technology_6502" title="MOS Technology 6502">6502A-based</a> processor design with up to 56 KB of memory and a proprietary OS, SDS-DOS, along with the <a href="BASIC_programming_language" class="mw-redirect" title="BASIC programming language">BASIC programming language</a> from <a href="Microsoft" title="Microsoft">Microsoft</a>. The SDS-420 featured a dual single-sided-double-density (400 KB per side) <a href="Floppy_disk" title="Floppy disk">floppy disk</a> drive, Model 70, manufactured by PerSci (Peripheral Sciences), of <a href="Santa_Monica%2C_California" title="Santa Monica, California">Santa Monica</a> and <a href="Marina_del_Rey%2C_California" title="Marina del Rey, California">Marina del Rey</a>, California. The SDS-422 Model offered some of the first dual double-sided-double-density floppy drives. Other hardware options were a <a href="MOS_Technology_6551" title="MOS Technology 6551">6551</a>-A <a href="Universal_synchronous_and_asynchronous_receiver-transmitter" title="Universal synchronous and asynchronous receiver-transmitter">USART</a> and a proprietary network SDS-NET using a <a href="Zilog_SCC" title="Zilog SCC">Z8530</a> SDLC/HDLC chip and software patterned after the early Xerox 3.0 <a href="Mbit/s" class="mw-redirect" title="Mbit/s">Mbit/s</a> <a href="Ethernet" title="Ethernet">Ethernet</a> and <a href="Transceiver" title="Transceiver">transceivers</a> produced by Tat Lam of the Bay Area.

The company sold about 1,000 machines worldwide, including Tahiti, London, Italy, New York City and Los Angeles. The 400 Series had little to do with <a href="Scientific_computing" class="mw-redirect" title="Scientific computing">scientific computing</a> and more with word processing and business services.

SDS announced a fully operational <a href="Local_area_network" title="Local area network">local area network</a> (LAN)-based <a href="File_server" title="File server">file server</a> called SDS-NET at <a href="COMDEX" title="COMDEX">COMDEX</a> in the early 1980s. SDS-NET was based on a Model 430 and written by Sam Keys, of <a href="Westchester%2C_California" class="mw-redirect" title="Westchester, California">Westchester, California</a>. The SDS 430 Server offered <a href="File_sharing" title="File sharing">file</a> and printer sharing services over SDS-NET or using a <a href="Modem" title="Modem">modem</a> and was based upon a 10 MB hard disk manufactured by Micropolis of Chatsworth, California. SDS Offered other models, including the SDS-410, a <a href="Diskless_workstation" class="mw-redirect" title="Diskless workstation">diskless workstation</a> that booted and ran off the SDS-NET or optionally could boot off-of and run over a 1200 bit/s modem link.

Products offered were: Word (word processing, written by John McCully, formerly of <a href="A_M_Jacquard_Systems" class="mw-redirect" title="A M Jacquard Systems">Jacquard Systems</a>, <a href="Manhattan_Beach%2C_California" title="Manhattan Beach, California">Manhattan Beach, California</a>), and fully functional accounting software: balance-forward and open-item accounting with <a href="General_Ledger" class="mw-redirect" title="General Ledger">General Ledger</a>, <a href="Accounts_Receivable" class="mw-redirect" title="Accounts Receivable">Accounts Receivable</a>, <a href="Accounts_Payable" class="mw-redirect" title="Accounts Payable">Accounts Payable</a>, and <a href="Payroll" title="Payroll">Payroll</a> (written by Tom Davies and Sandra Mass, both formerly with Jacquard Systems).

Other offerings included: Legal Time and Billing, Medical Time and Billing, and TTY an early terminal emulation program using the 6551 USART. Through partnerships with their <a href="Value-added_reseller" title="Value-added reseller">value-added resellers</a> (VARs) other software product offerings included a <a href="Solid-waste_management" class="mw-redirect" title="Solid-waste management">solid-waste management</a> system with automated truck routing and a country-club accounting package. One UK-based VAR was Jacq-Rite, a vertical market software house run by Ken Groome and Vivienne Gurney and based in <a href="Dorking" title="Dorking">Dorking</a>, <a href="Surrey" title="Surrey">Surrey</a>. Jacq-Rite had developed a range of specialist insurance software for the Jacquard machine but transferred to the SDS 400 following the advice of John McCully. Jacq-Rite installed several SDS 400 series networks in <a href="Lloyd's" class="mw-redirect" title="Lloyd's">Lloyd's</a> Managing and Members Agencies during 1982 and 1983. One of Jacq-Rite's programming staff that worked on the software porting was Justin Hill. Jacq-Rite's hardware sales were managed by David Ensor.

<div class="mw-heading mw-heading2"><h2 id="SDS_in_the_United_Kingdom">SDS in the United Kingdom</h2></div>

In 1983 Ensor and Hill left Jacq-Rite and formed a company calling itself 'Scientific Data Systems UK Limited' or 'SDS UK' (but actually unrelated to SDS) in <a href="Crawley%2C_West_Sussex" class="mw-redirect" title="Crawley, West Sussex">Crawley, West Sussex</a> in the UK. This coincided with SDS's announcement of their 4000 series computer; they hoped to build a business around this machine (including supplying it to Jacq-Rite) and negotiated an exclusive arrangement with SDS.

The SDS 4000 was a complete re-design, both cosmetically and with all-new internal hardware, but the architecture was basically the same as the 400 series - and ran the same software. The machine had a 1/2 height <style data-mw-deduplicate="TemplateStyles:r1154941027">

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</style>5+1⁄4-inch <a href="Hard_disk_drive" title="Hard disk drive">hard disk drive</a> bay and used <a href="Seagate_Technology" title="Seagate Technology">Seagate</a> 10 and 20 MB hard drives or <a href="SyQuest_Technology" title="SyQuest Technology">SyQuest</a> removable drive units. The 4000 motherboard had a <a href="SCSI" title="SCSI">SCSI</a> interface (still known as SASI at the time) and an <a href="Adaptec" title="Adaptec">Adaptec</a> 4000 SASI controller board was shoe-horned into the case to connect the drives. The diskette drive was also half-height 5+1⁄4-inch (the 400 series had used 8 inch diskettes). Like the 410, there was a diskless version too. Local Area Networking capabilities were carried over from the 400 series.

The 4000's major aesthetic departure from its predecessor was the use of a separate 12-inch tilt-and-swivel <a href="Computer_monitor" title="Computer monitor">Visual Display Unit</a> (VDU) and CPU case. The keyboard was detachable for the first time and the system had a beige colour scheme (dictated by the colour of the third party VDUs) in place of the black and white appearance of the 400.

However, financial problems at SDS were already substantial, and the UK business only ever received a small number of hastily completed machines. In an attempt to bypass these problems Hill produced a clone of the 4000 series computer by <a href="Reverse-engineering" class="mw-redirect" title="Reverse-engineering">reverse-engineering</a> an original model with the aid of a set of paper schematics obtained on a visit to SDS. This was neither approved nor supported by SDS, but Mitchell alone [and not Scheding] made a confidential visit to the UK to help debug the new computer. This was fortunate because, being unable to confer with SDS, Hill had unwittingly used schematics referring to a forthcoming revision of the machine, for which no <a href="Firmware" title="Firmware">firmware</a> had yet been completed. Mitchell alone [and not Scheding] finished the new firmware at SDS UK's offices. This meant that Hill's 'unofficial 4000' was actually a later revision than any US machines completed. Hill also improved the board layout, rear-panel connectivity and power supply.

The new machine worked, and a number of examples were made using a prototyping firm in <a href="Poole%2C_Dorset" class="mw-redirect" title="Poole, Dorset">Poole, Dorset</a>. Several were even sold, including a 5-station network with external storage (see below) to the UK <a href="Chartered_Institute_of_Legal_Executives" title="Chartered Institute of Legal Executives">Institute of Legal Executives</a> ('ILEX') in Bedford which remained in use for several years. This was supplied with bespoke software (also produced by Hill, with the assistance of Paula Flint) to store examination results and print certificates. However, any hope of selling into the lucrative Lloyd's insurance market in conjunction with Jacq-Rite was short-lived as Jacq-Rite had abandoned SDS and moved to the <a href="IBM_PC" class="mw-redirect" title="IBM PC">IBM PC</a> platform, taking their customers with them, as soon as SDS UK was formed. (This decision was also influenced by John McCully, who was now developing his word-processing software for <a href="MS-DOS" title="MS-DOS">MS-DOS</a>.)

The 'unofficial' 4000 series machine was at least a finished computer, and the small number produced worked reliably. Taking advantage of the <a href="SCSI" title="SCSI">SCSI</a> implementation, Hill added an external connector to his version of the machine and developed a matching hard drive enclosure. This enclosure accommodated higher capacity, full-height 5+1⁄4-inch drives.

However, the UK company's lack of <a href="Capital_(economics)" title="Capital (economics)">capital</a> to invest in the machine's manufacture meant that the cosmetic appearance of the computer left a lot to be desired. Furthermore, the machines were extremely costly – IBM's new <a href="PC/AT" class="mw-redirect" title="PC/AT">Personal Computer/AT</a> was shipping at about half the price SDS UK Limited needed to sell their computer for. Relationships between SDS and its UK namesake had broken down completely by this time, and SDS UK did not have the resources to develop new versions of the hardware or operating system.

SDS went out of business in the US 1984. The UK company of the same name ceased trading in the same year.

<div class="mw-heading mw-heading2"><h2 id="Computer_models">Computer models</h2></div>

<td>24-bit systems</td>

<td>first design, shipped along with the 920 in August 1962   high performance 920 with FPU and more memory (1963) less expensive but faster 920 (1964) major redesign (1963) 930 with additional support for time sharing (1966)

</td></tr>

<tr>

<td>12-bit system</td>

<td>"low end" machine (1965)

</td></tr>

<tr>

<td>16-bit systems</td>

<td><a href="SDS_Sigma_series" title="SDS Sigma series">SDS Sigma 2</a> <a href="SDS_Sigma_series" title="SDS Sigma series">SDS Sigma 3</a> CE16 & CF16</td>

<td>(1966) (1969) 1969

</td></tr>

<tr>

<td>32-bit systems</td>

<td><a href="SDS_Sigma_5" class="mw-redirect" title="SDS Sigma 5">SDS Sigma 5</a> <a href="SDS_Sigma_7" class="mw-redirect" title="SDS Sigma 7">SDS Sigma 6/7</a> <a href="SDS_Sigma_series" title="SDS Sigma series">Xerox Sigma 8/9</a></td>

<td>(1967) (1966) (1971)

</td></tr></tbody></table>

<div class="mw-heading mw-heading2"><h2 id="Known_users">Known users</h2></div>

Although initially intended as a Scientific Computer System, the 900 series and the Sigma series were used extensively in commercial <a href="Time-sharing" title="Time-sharing">time-sharing</a> systems. The biggest such user was <a href="Comshare" class="mw-redirect" title="Comshare">Comshare</a> Inc. of <a href="Ann_Arbor%2C_Michigan" title="Ann Arbor, Michigan">Ann Arbor, Michigan</a>, who extensively developed the hardware during the 1980s and the Sigma 9 was operated commercially until c. 1993. Developments and improvements by Comshare included the I-Channel, which allowed the utilization of Bus/Tag (IBM compatible) devices and the ISI Communications interface. These innovations allowed Comshare to capitalize on the Sigma CPU's and their software development (Commander II) by gaining access to current technology storage systems. When Xerox withdrew from the mainframe computer manufacturing business and relinquished all assets to Honeywell Corporation, Comshare opened a Research and Development facility in Phoenix Arizona, where they manufactured three Sigma 9 systems from spare and remanufactured parts acquired from Modutest, Inc. of <a href="Westlake_Village%2C_California" title="Westlake Village, California">Westlake Village, California</a> and Modutest Systems, Inc., <a href="Phoenix%2C_Arizona" title="Phoenix, Arizona">Phoenix, Arizona</a>. Recognition Equipment Inc. of <a href="Dallas" title="Dallas">Dallas</a>, <a href="Texas" title="Texas">Texas</a> used 910s in the 1960s to control its <a href="Optical_character_recognition" title="Optical character recognition">optical character recognition</a> machines.

Other known users of SDS systems in the USA include:

<table>

<ul><li><a href="Andrews_University" title="Andrews University">Andrews University</a> (Sigma 7)<a href="#cite_note-Calkins-5">[5]</a></li>

<li><a href="Ameren" title="Ameren">Central Illinois Light Company (CILCO)</a><a href="#cite_note-Calkins1-15">[15]</a></li>

<li><a href="Bucknell_University" title="Bucknell University">Bucknell University</a><a href="#cite_note-Kirkpatrick-16">[16]</a></li>

<li><a href="Caltrans" class="mw-redirect" title="Caltrans">Caltrans</a> (Sigma 5/7, Los Angeles District 5 freeway monitoring center)</li>

<li><a href="Carnegie_Mellon_University" title="Carnegie Mellon University">Carnegie Mellon University</a> (CMU) (Sigma 5, now at the <a href="Computer_History_Museum" title="Computer History Museum">Computer History Museum</a>)</li>

<li><a href="Cummins" title="Cummins">Cummins Engine Co.</a> (Sigma 9) Columbus, IN</li>

<li><a href="Delco_Electronics" title="Delco Electronics">Delco</a> (Sigma 7, Hybrid Simulation Lab, Goleta, CA)</li>

<li><a href="Eastman_Kodak" class="mw-redirect" title="Eastman Kodak">Eastman Kodak</a></li>

<li><a href="Grand_Valley_State_University" title="Grand Valley State University">Grand Valley State University</a> (Sigma 6, Allendale, MI)</li>

<li><a href="Grumman" title="Grumman">Grumman Aircraft Company</a> (Sigma 5/7 F-14A front seat simulator aka 2F95A at Pacific Missile Test Center, Pt. Mugu, CA)</li>

<li><a href="Hope_College" title="Hope College">Hope College</a> (Sigma 6) BTM for business and student records plus student online use. (Holland, MI)</li>

<li><a href="Hughes_Aircraft" class="mw-redirect" title="Hughes Aircraft">Hughes Aircraft</a> Company (Sigma 5/7 F-14A rear seat simulator aka 15C9A at Pacific Missile Test Center, Pt. Mugu)</li>

<li><a href="Jet_Propulsion_Laboratory" title="Jet Propulsion Laboratory">Jet Propulsion Laboratory</a>, Pasadena (Sigma 5/7, Deep Space Center, bldg 230)</li>

<li><a href="Johns_Hopkins_University" title="Johns Hopkins University">Johns Hopkins University</a>, Experimental Particle Physics Group (Sigma 7)</li>

<li>Los Alamos Scientific Laboratory (930)</li>

<li>Los Angeles County Roads (Sigma 3 traffic light control system)</li>

<li><a href="Marquette_University" title="Marquette University">Marquette University</a><a href="#cite_note-Calkins1-15">[15]</a> (Sigma 9)</li>

<li>Marquardt Aircraft Co., Van Nuys, Calif.</li>

<li><a href="McDonnell_Douglas" title="McDonnell Douglas">McDonnell Douglas</a><a href="#cite_note-Calkins1-15">[15]</a></li>

<li><a href="Michigan_State_University" title="Michigan State University">Michigan State University</a><a href="#cite_note-Calkins-5">[5]</a></li>

<li><a href="NASA" title="NASA">NASA</a> (Sigma 5 and Sigma 7 - <a href="Pioneer_program" title="Pioneer program">Pioneer Space Project</a>)</li>

<li><a href="OCLC" title="OCLC">Online Computer Library Center, Inc.</a> (OCLC)<a href="#cite_note-Calkins1-15">[15]</a> Sigma6 with OCLC modifications to handle attached IBM 1403 printer and NCR 25 MB removable disks. OP/SYS Software updates by Phillip Long.</li>

<li><a href="Queens_College%2C_City_University_of_New_York" title="Queens College, City University of New York">Queens College, City University of New York</a> (Sigma 7) - In Temp 1 building into at least the 1980s</li>

<li>Robert Plan Corporation<a href="#cite_note-Kirkpatrick-16">[16]</a></li>

<li><a href="Rochester_Institute_of_Technology" title="Rochester Institute of Technology">Rochester Institute of Technology</a> (RIT) (Sigma 6 academic/administrative computing)</li>

<li><a href="SRI_International" title="SRI International">Stanford Research Institute</a> (SRI) (used for "<a href="The_Mother_of_All_Demos" title="The Mother of All Demos">The Mother of All Demos</a>" on the <a href="NLS_(computer_system)" title="NLS (computer system)">oN-Line System</a> (NLS) in 1968)</li>

<li><a href="University_of_California%2C_Irvine" title="University of California, Irvine">University of California, Irvine</a> (UCI) Computing Center (Sigma 7)</li>

<li><a href="University_of_California%2C_Los_Angeles" title="University of California, Los Angeles">University of California, Los Angeles</a> (UCLA) (Sigma 7) "The first computer on the <a href="ARPANET" title="ARPANET">ARPANET</a>"</li>

<li><a href="University_of_Texas_at_Arlington" title="University of Texas at Arlington">University of Texas at Arlington</a> (UTA) (Sigma 7)<a href="#cite_note-Kirkpatrick-16">[16]</a></li>

<li>University of Texas at Austin (910, 930, Sigma 5)</li>

<li><a href="University_of_Vermont" title="University of Vermont">University of Vermont</a> (Sigma 7)</li>

<li><a href="University_of_Wisconsin%E2%80%93Green_Bay" title="University of Wisconsin–Green Bay">University of Wisconsin–Green Bay</a><a href="#cite_note-Calkins1-15">[15]</a></li>

<li><a href="University_of_Wyoming" title="University of Wyoming">University of Wyoming</a> (Sigma 5/7)<a href="#cite_note-Kirkpatrick-16">[16]</a></li>

<li><a href="Vandenberg_Air_Force_Base" class="mw-redirect" title="Vandenberg Air Force Base">Vandenberg Air Force Base</a> (Sigma 5/7 data reduction system at South Base)</li>

<li><a href="Vanderbilt_University" title="Vanderbilt University">Vanderbilt University</a><a href="#cite_note-Kirkpatrick-16">[16]</a></li>

<li>Warner Computer Systems, Inc.<a href="#cite_note-Calkins1-15">[15]</a></li>

<li><a href="Washington_Metropolitan_Area_Transit_Authority" title="Washington Metropolitan Area Transit Authority">Washington Metropolitan Area Transit Authority</a> (WMATA)<a href="#cite_note-Calkins1-15">[15]</a></li>

<li><a href="Whirlpool_Corporation" title="Whirlpool Corporation">Whirlpool</a> (Sigma 3 RTM) (Life testing appliances, Benton Harbor, MI)</li>

<li><a href="Wright-Patterson_Air_Force_Base" title="Wright-Patterson Air Force Base">Wright-Patterson Air Force Base</a> (A/D Flight simulation, Dayton, OH)</li></ul>

</td>

<ul><li><a href="Youngstown_Sheet_and_Tube" title="Youngstown Sheet and Tube">Youngstown Sheet and Tube</a> research lab was running a Sigma 5 as a <a href="Hybrid_computer" title="Hybrid computer">Hybrid computer</a> with an AD 4 analog computer for projects like multiphase diffusion.</li>

<li>The <a href="United_States_Air_Force_Academy" title="United States Air Force Academy">United States Air Force Academy</a> (Sigma 5)</li>

<li>Exploration Data Consultants Lakewood Colorado (Sigma 5)</li>

<li><a href="Martin_Marietta" title="Martin Marietta">Martin Marietta</a> Denver Aerospace Division (4 Sigma 7 for the MOL Program, SDS-930/Sigma 9 at Digidat division)</li>

<li>Martin Marietta Dewey Rocky Mountain Cement, Lyons, Colorado (Sigma 2)</li>

<li><a href="United_States_Air_Force" title="United States Air Force">USAF</a> <a href="Buckley_AFB" class="mw-redirect" title="Buckley AFB">Buckley AFB</a>, Colorado (Sigma 3)</li>

<li>USAF <a href="Nellis_AFB" class="mw-redirect" title="Nellis AFB">Nellis AFB</a>, Nevada (6 Sigma 9's ACEVAL/AIMVAL Project CUBIC ACMI systems)</li>

<li>USAF Nellis AFB, Nevada (2 Sigma 9's NTTR Range Control Operations)</li>

<li>US Navy Yuma Arizona "Top Gun" CUBIC ACMI System (Sigma 5)</li>

<li><a href="Hughes_Aircraft_Company" title="Hughes Aircraft Company">Hughes Aircraft Company</a>, Burbank, California (Sigma 7)</li>

<li>Global Marine <a href="Glomar_Explorer" title="Glomar Explorer">Glomar Explorer</a> research vessel (Sigma 2)</li>

<li><a href="University_of_Southern_Mississippi" title="University of Southern Mississippi">University of Southern Mississippi</a>, Hattiesburg (Sigma 9)</li>

<li><a href="Pacific_Bell" title="Pacific Bell">Pacific Bell Telephone</a>, Seattle, Washington (Sigma 3)</li>

<li><a href="Montana_State_University" title="Montana State University">Montana State University</a>, Bozeman (Sigma 7)</li>

<li><a href="National_Bureau_of_Standards" class="mw-redirect" title="National Bureau of Standards">National Bureau of Standards</a>, Boulder, Colorado (SDS-940)</li>

<li>Naval Nuclear Lab Idaho Falls Idaho (Sigma 5)</li>

<li><a href="Sunspot_Solar_Observatory" title="Sunspot Solar Observatory">Sunspot Solar Observatory</a>, Cloudcroft, New Mexico (Sigma 2, Sigma 5)</li>

<li><a href="Motorola" title="Motorola">Motorola Electronics</a>, Scottsdale, Arizona (Sigma 5, Sigma 9)</li>

<li><a href="United_Airlines" title="United Airlines">United Airlines</a> Flight Training Center, Denver, Colorado (Sigma 5 LINK and Redifon flight Simulators)</li>

<li>USAF <a href="Luke_AFB" class="mw-redirect" title="Luke AFB">Luke AFB</a>, Arizona (Sigma 5 LINK Simulator)</li>

<li><a href="Salt_River_Project" title="Salt River Project">Salt River Project</a>, Phoenix, Arizona (Sigma 2)</li>

<li><a href="Arizona_Public_Service" class="mw-redirect" title="Arizona Public Service">Arizona Public Service</a>, Phoenix, Arizona (Sigma 5)</li>

<li><a href="Tennessee_Valley_Authority" title="Tennessee Valley Authority">Tennessee Valley Authority</a> (Sigma 5)</li>

<li>Dallas Power and Light (Sigma 5)</li>

<li><a href="Carolina_Power_%26_Light_Company" title="Carolina Power & Light Company">Carolina Power and Light</a> (Sigma 5)</li>

<li><a href="Conoco" title="Conoco">Conoco Corporation</a>, Ponca City, Oklahoma (Sigma 7, Sigma 9)</li>

<li>Space Data Corporation (Sigma 5 White Sands & Poker Flat Alaska)</li>

<li><a href="Los_Alamos_National_Laboratory" title="Los Alamos National Laboratory">Los Alamos National Laboratory</a> (Sigma 2)</li>

<li><a href="Lawrence_Livermore_National_Laboratory" title="Lawrence Livermore National Laboratory">Lawrence Livermore National Laboratory</a> (Sigma 7)</li></ul>

</td></tr></tbody></table>

Known users outside the U.S. include:

<table>

<ul><li><a href="British_Airways" title="British Airways">British Airways</a> (Sigma 2 & 3 - Flight Simulation)</li>

<li>Link Simulation (Lansing)</li>

<li><a href="WS_Atkins" class="mw-redirect" title="WS Atkins">WS Atkins</a> Engineering (Epsom)</li>

<li><a href="British_Aerospace" title="British Aerospace">British Aerospace</a> (Wharton) (Dual Sigma 5 - MRCA (Tornado) Flight Telemetry)</li>

<li><a href="Carleton_University" title="Carleton University">Carleton University</a> (Sigma 9)</li>

<li>Comshare (London)</li>

<li>Cybernetics Research Consultants (Slough)</li>

<li>Dornier System ( Immenstaad Germany ) MUDAS- & CAMAC-cross-Assembler and other.</li>

<li><a href="Rank_Xerox" title="Rank Xerox">Rank Xerox</a> (Denham)</li>

<li>Rank Radio International (Plymouth)</li>

<li><a href="Royal_Naval_Engineering_College" title="Royal Naval Engineering College">Royal Naval Engineering College</a> (Manadon)</li>

<li><a href="Warwick_University" class="mw-redirect" title="Warwick University">Warwick University</a> (Sigma 5 - Braille Printer Research)</li>

<li><a href="Liverpool_University" class="mw-redirect" title="Liverpool University">Liverpool University</a> (Sigma 2 - Particle Research)</li>

<li><a href="Addenbrooke's_Hospital" title="Addenbrooke's Hospital">Addenbrooke's Hospital</a> (Cambridge)</li>

<li><a href="Charing_Cross_Hospital" title="Charing Cross Hospital">Charing Cross Hospital</a> (London)</li>

<li><a href="University_College_Hospital" title="University College Hospital">University College Hospital</a> (London)</li>

<li><a href="Rolls-Royce_and_Associates" class="mw-redirect" title="Rolls-Royce and Associates">Rolls-Royce and Associates</a> (550 - Submarine Power Plant Research)</li>

<li><a href="St_Thomas'_Hospital" title="St Thomas' Hospital">St Thomas' Hospital</a> (London)</li>

<li>Government Chemist</li>

<li>N.G.T.E. Pyestock (<a href="National_Gas_Turbine_Establishment" title="National Gas Turbine Establishment">National Gas Turbine Establishment</a>, AKA Ministry of Public Buildings)</li>

<li>J. Sefel</li></ul>

</td>

<ul><li>Watsons (Insurance) Redhill</li>

<li><a href="A%26AEE" class="mw-redirect" title="A&AEE">A&AEE</a> Boscombe Down (Sigma 5 - MRCA (Tornado) Flight Telemetry)</li>

<li><a href="RAE_Bedford" title="RAE Bedford">RAE Bedford</a> (Sigma 9 flight simulator)</li>

<li><a href="Cambridge_University" class="mw-redirect" title="Cambridge University">Cambridge University</a> Department of Engineering (Sigma 6)</li>

<li>SMRE - Safety in Mines Research Establishment - Sheffield</li>

<li><a href="Aeritalia" title="Aeritalia">Aeritalia</a> Turin (Sigma 5 - MRCA (Tornado) Flight Telemetry)</li>

<li><a href="Messerschmitt-B%C3%B6lkow-Blohm" title="Messerschmitt-Bölkow-Blohm">MBB</a> Munich (Sigma 5 - MRCA (Tornado) Flight Telemetry)</li>

<li><a href="Imperial_Chemical_Industries" title="Imperial Chemical Industries">ICI</a> North England (Sigma 2, 3, 5 - Chemical Plant Control)</li>

<li><a href="Sonatrach" title="Sonatrach">Sonatrach</a> (Algeria)</li>

<li>Rank Xerox (Milan)</li>

<li>American Israeli Paper Mills (Israel)</li>

<li><a href="Israeli_Navy" title="Israeli Navy">Israeli Navy</a> (560)</li>

<li><a href="Israeli_Air_Force" title="Israeli Air Force">IAF</a> Aircraft (Israel) (Sigma 5 - Flight Telemetry)</li>

<li>AKU Studsvik (Sweden) (Dual Sigma 9 - Nuclear Power Station Simulators)</li>

<li><a href="Vattenfall" title="Vattenfall">Vattenfall</a> Vällingby (Sweden) (Dual Sigma 9 - Electricity Grid Monitoring)</li>

<li>West Chester University (Sigma 9 and X560)</li>

<li><a href="University_of_Toronto_Libraries" title="University of Toronto Libraries">UTLAS</a> (prev. University of Toronto Library Automation Systems) (Sigma 5, 7, 9)</li>

<li><a href="Dalhousie_University" title="Dalhousie University">Dalhousie University</a> (Sigma 5 with Honeywell memory mapping upgrade)</li>

<li><a href="Mitsubishi_Heavy_Industries" title="Mitsubishi Heavy Industries">Mitsubishi Heavy Industries</a> Tsuruga Japan (Sigma 5 - Nuclear Core Simulator)</li></ul>

</td></tr></tbody></table>

<div class="mw-heading mw-heading2"><h2 id="SDS_software">SDS software</h2></div>

The primary operating system for the 900 series was called Monarch. For the Sigma 32-bit range RBM, a real-time and batch monitor, and BTM, a batch and timesharing monitor were available. In 1971 a more sophisticated timesharing system <a href="Universal_Time-Sharing_System" title="Universal Time-Sharing System">UTS</a> was released, which was developed into <a href="CP-V_operating_system" class="mw-redirect" title="CP-V operating system">CP-V</a>. The RBM operating system was replaced by CP-R, a real-time and timesharing system. In March 1982 Honeywell gave the remaining software for the 900 series to a group in Kansas City that offered to continue making copies for people still using the systems. Honeywell had stopped supporting the systems many years before this. In September 2006, this collection was donated to the <a href="Computer_History_Museum" title="Computer History Museum">Computer History Museum</a> along with all of the program's original documentation, and copies of most of the SDS user's manuals. This is one of the largest collections of software to have survived from the 1960s intact. Unfortunately, the timesharing software for the 940 series was not present in the Honeywell LADS Library and does not appear to have survived. Copies of the original system developed at <a href="UC_Berkeley" class="mw-redirect" title="UC Berkeley">UC Berkeley</a> exist as file system backups. Most of the customers for 940 systems (in particular Tymshare) made extensive modifications to the 940 system software, and no copies of that version of the software are known to have survived.

Multiple simulators for the Sigma series are known to exist, and Sigma series software is being collected by the <a href="Computer_History_Museum" title="Computer History Museum">Computer History Museum</a>. Early versions were not copyrighted (CP-V C00 and earlier), while later versions developed by Honeywell were (CP-V E00 and F00). Some copies of CP-V D00 were released without licensing agreements and subsequently public domain status was claimed by users.

The Xerox CE16 and CF16 <a href="Minicomputer" title="Minicomputer">minicomputers</a>, announced in May 1969, were small 16-bit computers designed primarily for process control applications. Both systems came with a base 4 KW of 16-bit core memory, expandable to 16 KW, and three "interrupt channels." The CE16 CPU can perform an addition in 16 μsec and a (software) multiplication in 126 μsec. Its price of $12,800 was equivalent to $109,752 in 2024. The CF16 CPU is rated at 5.33 μsec for addition and 42 μsec for (hardware) multiplication. It cost $14,900, equivalent to $127,759 in 2024.<a href="#cite_note-17">[17]</a><a href="#cite_note-18">[18]</a>

<ul><li><a href="Berkeley_Timesharing_System" title="Berkeley Timesharing System">Berkeley Timesharing System</a></li>

<li><a href="SDS_9xx_computers" class="mw-redirect" title="SDS 9xx computers">SDS 9xx computers</a></li></ul>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

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</style><cite id="CITEREFGregory2018" class="citation book cs1">Gregory, Nathan (Mar 16, 2018). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=UIFcDwAAQBAJ&pg=PA85">The Tym Before ...</a> Lulu. p. 85. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-387-30405-9</bdi>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20221217093134/https://books.google.com/books?id=UIFcDwAAQBAJ&pg=PA85">Archived</a> from the original on December 17, 2022. Retrieved Feb 15, 2020.</cite>

</li>

<li id="cite_note-2"><a href="#cite_ref-2">^</a> <cite id="CITEREFScientific_Data_Systems" class="citation web cs1">Scientific Data Systems. <a rel="nofollow" class="external text" href="https://www.yumpu.com/en/document/view/42710052/sds-900-series-1965-ca">"SDS 900 series"</a>. yumpu.com. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200215171935/https://www.yumpu.com/en/document/view/42710052/sds-900-series-1965-ca">Archived</a> from the original on February 15, 2020. Retrieved Feb 15, 2020.</cite>

</li>

<li id="cite_note-3"><a href="#cite_ref-3">^</a> A programmed operator was a hardware concept on the SDS 900 series of computers similar to the concept of the <a href="Atlas_Computer_(Manchester)" class="mw-redirect" title="Atlas Computer (Manchester)">Atlas computer</a>'s "extracodes". The programmed operator calling mechanism allowed computer operation codes to be interpreted by software code. See Scientific Data Systems, <a rel="nofollow" class="external text" href="http://archive.computerhistory.org/resources/text/SDS/SDS.900.1962.102646286.pdf">"SDS 900 Series"</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20081218041721/http://archive.computerhistory.org/resources/text/SDS/SDS.900.1962.102646286.pdf">Archived</a> 2008-12-18 at the <a href="Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, technical manual. Cf. Programmed Operator. Also see <a rel="nofollow" class="external text" href="http://bitsavers.org/pdf/sds/9xx/910/900008D_910_RefMan_Feb70.pdf">"SDS 910 Reference Manual"</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110117070553/http://www.bitsavers.org/pdf/sds/9xx/910/900008D_910_RefMan_Feb70.pdf">Archived</a> 2011-01-17 at the <a href="Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, February 1970. Cf. Appendix E. page A-19, "Programmed Operators" for an in-depth discussion of Programmed Operators.

</li>

<li id="cite_note-4"><a href="#cite_ref-4">^</a> Bell, Gordon, <a rel="nofollow" class="external text" href="http://research.microsoft.com/en-us/um/people/gbell/Computer_Structures__Readings_and_Examples/00000295.htm">"Computer Structures: Readings and Examples"</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20081226125041/http://research.microsoft.com/en-us/um/people/gbell/Computer_Structures__Readings_and_Examples/00000295.htm">Archived</a> 2008-12-26 at the <a href="Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, Section 6: Processors with multiprogramming ability, p.275. "The [SDS] 940 uses a memory map which is almost a subset of that of Atlas but is more modest than that of the IBM 360/67 [Arden et al., 1966] and GE 645 [Dennis, 1965; Daley and Dennis, 1968]. A number of instructions are apparently built in via the programmed operator calling mechanism, based on Atlas extracodes (Chap. 23). The software-defined instructions emphasize the need for hardware features. For example, floating-point arithmetic is needed when several computer-bound programs are run. The SDS 945 is a successor to the 940, with slightly increased capability but at a lower cost."

</li>

<li id="cite_note-Calkins-5">^ <a href="#cite_ref-Calkins_5-0">a</a> <a href="#cite_ref-Calkins_5-1">b</a> <a href="#cite_ref-Calkins_5-2">c</a> <a href="#cite_ref-Calkins_5-3">d</a> <cite id="CITEREFKeith_G._Calkins1984" class="citation web cs1">Keith G. Calkins (June 1984). <a rel="nofollow" class="external text" href="http://www.andrews.edu/~calkins/profess/SDSigma7.htm">"The Computer That Will Not Die: The SDS SIGMA 7"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110525174115/http://www.andrews.edu/~calkins/profess/SDSigma7.htm">Archived</a> from the original on 25 May 2011. Retrieved 15 May 2011.</cite>

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<li id="cite_note-SDS92Ref-6">^ <a href="#cite_ref-SDS92Ref_6-0">a</a> <a href="#cite_ref-SDS92Ref_6-1">b</a> <a href="#cite_ref-SDS92Ref_6-2">c</a> <a href="#cite_ref-SDS92Ref_6-3">d</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.bitsavers.org/pdf/sds/92/900505C_SDS_92_Reference_Jun65.pdf">"SDS 92 Reference Manual"</a> (PDF). www.bitsavers.org. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200327193614/http://bitsavers.org/pdf/sds/92/900505C_SDS_92_Reference_Jun65.pdf">Archived</a> (PDF) from the original on March 27, 2020. Retrieved March 16, 2019.</cite>

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<li id="cite_note-7"><a href="#cite_ref-7">^</a> <cite id="CITEREFBrock1975" class="citation book cs1">Brock, Gerald W. (1975). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=jfyvXAOhWXAC&q=%22SDS+92%22+delivered">The U.S. computer industry: a study of market power</a>. Ballinger Pub. Co. p. 192. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>9780884102618</bdi>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20221217093202/https://books.google.com/books?id=jfyvXAOhWXAC&q=%22SDS+92%22+delivered">Archived</a> from the original on 2022-12-17. Retrieved 2020-12-04. <q>That same month [April 1965] Scientific Data Systems delivered the first commercial integrated circuit computer, the SDS-92.</q></cite>

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<li id="cite_note-8"><a href="#cite_ref-8">^</a> <cite id="CITEREFPughJohnsonPalmer1991" class="citation book cs1">Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H. (1991). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=MFGj_PT_clIC&q=%22sds+92%22&pg=PA440">IBM's 360 and Early 370 Systems</a>. MIT Press. p. 440. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>9780262161237</bdi>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230813085115/https://books.google.com/books?id=MFGj_PT_clIC&q=%22sds+92%22&pg=PA440">Archived</a> from the original on 2023-08-13. Retrieved 2020-12-04.</cite>

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<li id="cite_note-9"><a href="#cite_ref-9">^</a> <cite class="citation book cs1"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=cY0TAAAAIAAJ&q=%22sds+92%22">The Industrial Reorganization Act</a>. Columns: computer, solid state?, avg monthly rentals, date of 1st installation, number of installations, number of unfilled orders. 1974. p. 5577. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230813085111/https://books.google.com/books?id=cY0TAAAAIAAJ&q=%22sds+92%22">Archived</a> from the original on 2023-08-13. Retrieved 2020-12-04.</cite><code class="cs1-code">{{cite book}}</code>: CS1 maint: others (link)

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<li id="cite_note-10"><a href="#cite_ref-10">^</a> <cite id="CITEREFScientific_Data_Systems1965" class="citation book cs1">Scientific Data Systems (June 1965). <a rel="nofollow" class="external text" href="http://bitsavers.trailing-edge.com/pdf/sds/92/900505C_SDS_92_Reference_Jun65.pdf">Reference Manual SDS 92 Computer</a> (PDF). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140924053626/http://bitsavers.trailing-edge.com/pdf/sds/92/900505C_SDS_92_Reference_Jun65.pdf">Archived</a> (PDF) from the original on September 24, 2014. Retrieved Sep 20, 2014.</cite>

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<li id="cite_note-11"><a href="#cite_ref-11">^</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.uwgb.edu/UWGBCMS/media/Catalog/files/1984-1986_GRAD.pdf">"Graduate Studies Catalog"</a> (PDF). UW-Green bay. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200711121245/https://www.uwgb.edu/UWGBCMS/media/Catalog/files/1984-1986_GRAD.pdf">Archived</a> (PDF) from the original on July 11, 2020. Retrieved July 9, 2020.</cite>

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<li id="cite_note-12"><a href="#cite_ref-12">^</a> <cite id="CITEREFSpin" class="citation web cs1">Spin, William A. <a rel="nofollow" class="external text" href="https://nautilus.org/wp-content/uploads/2012/09/413-William-A.-Spin.pdf">"ANNUAL HISTORICAL REVIEW KWAJALEIN MISSILE RANGE"</a> (PDF). Nautilus Institute. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200709213228/https://nautilus.org/wp-content/uploads/2012/09/413-William-A.-Spin.pdf">Archived</a> (PDF) from the original on July 9, 2020. Retrieved July 9, 2020.</cite>

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<li id="cite_note-13"><a href="#cite_ref-13">^</a> <cite id="CITEREFMcMurran2008" class="citation book cs1">McMurran, Marshall William (2008). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=UU3v0tbq8acC&pg=PA393">Achieving Accuracy: A Legacy of Computers and Missiles</a>. Xlibris Corporation. p. 104. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4363-8107-9</bdi>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200807043943/https://books.google.com/books?id=UU3v0tbq8acC&pg=PA393">Archived</a> from the original on August 7, 2020. Retrieved Jul 9, 2020.</cite>

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<li id="cite_note-14"><a href="#cite_ref-14">^</a> <cite id="CITEREFRosenberg1979" class="citation news cs1">Rosenberg, Marcy (Feb 12, 1979). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=sglMaWvdPEUC&q=%22SDS+420%22&pg=RA1-PA111">"SDS Resurfaces With Same Name, New Target"</a>. Computerworld. Vol. XIII, no. 7. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230909011940/https://books.google.com/books?id=sglMaWvdPEUC&q=%22SDS+420%22&pg=RA1-PA111">Archived</a> from the original on September 9, 2023. Retrieved Nov 6, 2015.</cite>

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<li id="cite_note-Calkins1-15">^ <a href="#cite_ref-Calkins1_15-0">a</a> <a href="#cite_ref-Calkins1_15-1">b</a> <a href="#cite_ref-Calkins1_15-2">c</a> <a href="#cite_ref-Calkins1_15-3">d</a> <a href="#cite_ref-Calkins1_15-4">e</a> <a href="#cite_ref-Calkins1_15-5">f</a> <a href="#cite_ref-Calkins1_15-6">g</a> <cite id="CITEREFCalkins" class="citation web cs1">Calkins, Keith. <a rel="nofollow" class="external text" href="http://www.andrews.edu/~calkins/profess/sigma.htm">"Former Sigma sites"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20150206072552/http://www.andrews.edu/~calkins/profess/sigma.htm">Archived</a> from the original on February 6, 2015. Retrieved August 29, 2013.</cite>

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<li id="cite_note-Kirkpatrick-16">^ <a href="#cite_ref-Kirkpatrick_16-0">a</a> <a href="#cite_ref-Kirkpatrick_16-1">b</a> <a href="#cite_ref-Kirkpatrick_16-2">c</a> <a href="#cite_ref-Kirkpatrick_16-3">d</a> <a href="#cite_ref-Kirkpatrick_16-4">e</a> <cite id="CITEREFKirkpatrick" class="citation web cs1">Kirkpatrick, Jim. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210421230200/http://w3.uwyo.edu/~jimkirk/sigma_era.html">"The Sigma Era"</a>. Archived from <a rel="nofollow" class="external text" href="http://w3.uwyo.edu/~jimkirk/sigma_era.html">the original</a> on April 21, 2021. Retrieved July 17, 2023.</cite>

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<li id="cite_note-17"><a href="#cite_ref-17">^</a> <cite class="citation magazine cs1"><a rel="nofollow" class="external text" href="http://bitsavers.trailing-edge.com/magazines/Datamation/196905.pdf">"controller/computers"</a> (PDF). Datamation. Vol. 15, no. 5. May 1969. p. 193. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230718194304/http://bitsavers.trailing-edge.com/magazines/Datamation/196905.pdf">Archived</a> (PDF) from the original on July 18, 2023. Retrieved July 18, 2023.</cite>

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<li id="cite_note-18"><a href="#cite_ref-18">^</a> <cite class="citation magazine cs1"><a rel="nofollow" class="external text" href="http://bitsavers.trailing-edge.com/magazines/Modern_Data/Modern_Data_1969_08.pdf">"Technology Profile: Mini-Computers"</a> (PDF). Modern Data. Vol. 2, no. 8. August 1969. p. 61. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230718194317/http://bitsavers.trailing-edge.com/magazines/Modern_Data/Modern_Data_1969_08.pdf">Archived</a> (PDF) from the original on July 18, 2023. Retrieved July 18, 2023.</cite>

</li>

</ol></div></div>

<div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2></div>

<ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20080220092745/http://www.time.com/time/magazine/article/0,9171,899454,00.html">"Enter Max Palevsky"</a>, <a href="Time_(magazine)" title="Time (magazine)">Time Magazine</a>, Friday, February 24, 1967</li></ul>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

<ul><li><a rel="nofollow" class="external text" href="http://purl.umn.edu/107640">Oral history interview with Paul A. Strassmann</a>, <a href="Charles_Babbage_Institute" class="mw-redirect" title="Charles Babbage Institute">Charles Babbage Institute</a>, University of Minnesota, Minneapolis</li>

<li><a rel="nofollow" class="external text" href="http://archive.computerhistory.org/resources/text/SDS/SDS.Sigma.1967.102646100.pdf">Scientific Data Systems The Sigma Family: Introducing Sigma from Scientific Data Systems. 1967</a></li>

<li><a rel="nofollow" class="external text" href="http://www.andrews.edu/~calkins/profess/SDSigma7.htm">SDS Sigma 7 technical information</a></li>

<li><a rel="nofollow" class="external text" href="http://bitsavers.org/pdf/sds/9xx">SDS 900 series documentation at bitsavers.org</a></li>

<li><a rel="nofollow" class="external text" href="http://bitsavers.org/pdf/sds/sigma">Sigma series documentation at bitsavers.org</a></li>

<li><a rel="nofollow" class="external text" href="http://bitsavers.org/pdf/sds/tymshare">Tymshare documentation at bitsavers.org</a></li></ul></div><div><div class="zim-footer">

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