The SDS 930 was a commercial

24-bit Notable 24-bit machines include the CDC 924 – a 24-bit version of the CDC 1604, CDC lower 3000 series, SDS 930 and SDS 940, the ICT 1900 series, the Elliott 4100 series, and the Datacraft minicomputers/Harris H series. The term SWORD i ...

computer using

bipolar junction transistor A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipola ...

s sold by

Scientific Data Systems Scientific Data Systems (SDS), was an American computer company founded in September 1961 by Max Palevsky and Robert Beck, veterans of Packard Bell Corporation and Bendix, along with eleven other computer scientists. SDS was an early adopter of i ...

. It was announced in December 1963, with first installations in June 1964.

Description

An SDS 930 system consists of at least three standard () cabinets, weighing about . It is composed of an arithmetic and logic unit, at least 8,192 words (24-bit + simple

parity bit A parity bit, or check bit, is a bit added to a string of binary code. Parity bits are a simple form of error detecting code. Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes) ...

)

magnetic-core memory Magnetic-core memory was the predominant form of random-access computer memory for 20 years between about 1955 and 1975. Such memory is often just called core memory, or, informally, core. Core memory uses toroids (rings) of a hard magneti ...

, and the IO unit.

Two's complement Two's complement is a mathematical operation to reversibly convert a positive binary number into a negative binary number with equivalent (but negative) value, using the binary digit with the greatest place value (the leftmost bit in big- endian ...

integer arithmetic is used. The machine has integer multiply and divide, but no floating-point hardware. An optional correlation and filtering unit (CFE) can be added, which is capable of very fast floating-point multiply-add operations (primarily intended for digital signal processing applications). A free-standing console is also provided, which includes binary displays of the machine's registers and switches to boot and debug programs. User input is by a

Teletype A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Init ...

Model 35 ASR unit and a high-speed paper-tape reader (300 cps). Most systems include at least two magnetic-tape drives, operating at up to 75 in/s at 800 bpi. The normal variety of peripherals is also available, including magnetic-drum units, card readers and punches, and an extensive set of analog-digital/digital-analog conversion devices. A (vector mode) graphic display unit is also available, but it does not include a means of keyboard input. The SDS 930 is a typical small- to medium-scale scientific computer of the 1960s. Speed is good for its cost, but with an integer add time of 3.5 microseconds, it is not in the same league as the scientific workhorses of the day (the

CDC 6600 The CDC 6600 was the flagship of the 6000 series of mainframe computer systems manufactured by Control Data Corporation. Generally considered to be the first successful supercomputer, it outperformed the industry's prior recordholder, the IBM ...

, for example). A well equipped 930 can easily exceed 10 cabinets and require a climate-controlled room. The price of such a system in 1966 would be in the neighborhood of $500K. Programming languages available include FORTRAN II, ALGOL 60, and the assembly language known as Meta-Symbol. The FORTRAN system is very compact, having been designed and implemented by Digitek for SDS to compile and run in 4,096 word SDS 900 series machines. To do anything useful in such small memory space, the compiler relies on an SDS architectural feature known as Programmed OPeratorS, or POPS. This feature consists of a single bit in the instruction word that causes the machine to "mark place and branch" to the memory address of the instruction code value plus 100 (octal). As a result, pseudo instructions can be defined and implemented yielding very compact special-purpose code. Both the FORTRAN compiler and runtime take advantage of this capability. Towards the end of the SDS 930's market lifetime a real-time monitor system was introduced, which included a FORTRAN IV compiler. Neither the operating system nor the compiler were used heavily by customers. Many organizations modified and enhanced the 930's hardware.

Project Genie Project Genie was a computer research project started in 1964 at the University of California, Berkeley. It produced an early time-sharing system including the Berkeley Timesharing System, which was then commercialized as the SDS 940. History ...

at the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...

, added hardware to permit time-sharing with the

Berkeley Timesharing System The Berkeley Timesharing System was a pioneering time-sharing operating system implemented between 1964 and 1967 at the University of California, Berkeley. It was designed as part of Project Genie and marketed by Scientific Data Systems for the ...

. These changes later formed the basis for the SDS 940. Other operating systems were also written for the machine by customers, including Arachnid (Spider) at the University of Texas at Austin. SDS 930s could be found at most of the major US government labs at the time, including Los Alamos Scientific Laboratory. Early

flight simulator A flight simulator is a device that artificially re-creates aircraft flight and the environment in which it flies, for pilot training, design, or other purposes. It includes replicating the equations that govern how aircraft fly, how they rea ...

s used the SDS 930, because of its hardware integer multiply and divide capability and its real-time data acquisition and control peripheral modules. The machines are particularly well suited to this and other kinds of data acquisition and real-time analysis, as well as to serving as a digital control system for analog-hybrid systems. The Surface Ship

ASW ASW, a three-letter abbreviation, may refer to: * an Associate Clinical Social Worker (ASW) in the state of California * High-temperature insulation wool#alumino silicate wool *Asynchronous SpaceWarp, a framerate smoothing technique used on the Ocul ...

Attack Trainer (Device 14A2A) used a SDS 930 computer and was designed to train the ASW attack team of a

US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

destroyer in submarine warfare by providing realistic simulations ashore with cost savings in operating time and expense at sea. Sophisticated ASW Devices Now Operating in the Navy. Naval Training Bulletin. Winter 1966-1967. page 34-38. https://books.google.com/books?id=j0lepyMcE-sC By 1974 estimates, there were about 200 SDS-930/940/945 computers still installed.

References

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External links

SDS 900-series documents at bitsavers.org
(archived 2008) Scientific Data Systems computers Transistorized computers 24-bit computers

Description

See also

References

External links