Sylvania's MOBIDIC, short for "MOBIle DIgital Computer", was a transistorized computer intended to store, sort and route information as one part of the

United States Army The United States Army (USA) is the land warfare, land military branch, service branch of the United States Armed Forces. It is one of the eight Uniformed services of the United States, U.S. uniformed services, and is designated as the Army o ...

's Fieldata concept. Fieldata aimed to automate the distribution of battlefield data in any form, ensuring the delivery of reports to the proper recipients regardless of the physical form they were sent or received. MOBIDIC was mounted in the trailer of a

semi-trailer A semi-trailer is a trailer without a front axle. In the United States, the term is also used to refer to the combination of a truck and a semi-trailer; a tractor-trailer. A large proportion of a semi-trailer's weight is supported by a trac ...

truck, while a second supplied power, allowing it to be moved about the battlefield. The Army referred to the system as the AN/MYK-1, or AN/MYK-2 for the dual-CPU version, Sylvania later offered a commercial version as the S 9400.

History

In early 1956 the

Army Signal Corps The United States Army Signal Corps (USASC) is a branch of the United States Army that creates and manages communications and information systems for the command and control of combined arms forces. It was established in 1860, the brainchild of Ma ...

Fort Monmouth Fort Monmouth is a former installation of the Department of the Army in Monmouth County, New Jersey. The post is surrounded by the communities of Eatontown, Tinton Falls and Oceanport, New Jersey, and is located about from the Atlantic Ocean. T ...

released a contract tender for the development of a van-mounted mobile computer as part of their Fieldata efforts. Fieldata envisioned a system where any sort of reports would be converted into text format and then sent electronically around an extended battlefield. At the recipient's end, it would be converted into an appropriate output, often on a

line printer A line printer prints one entire line of text before advancing to another line. Most early line printers were impact printers. Line printers are mostly associated with unit record equipment and the early days of digital computing, but the ...

or similar device. By automating the process of routing the messages in the middle of the information flow, the Signal Corps was hoping to guarantee delivery and improve responsiveness. Fieldata can be thought of as a general purpose version of the system the

US Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sig ...

was developing in their

SAGE system Sage or SAGE may refer to: Plants * ''Salvia officinalis'', common sage, a small evergreen subshrub used as a culinary herb ** Lamiaceae, a family of flowering plants commonly known as the mint or deadnettle or sage family ** ''Salvia'', a large ...

, which did the same task but limited to the field of information about aircraft locations and status. The heart of Fieldata would be computer systems that would receive, store, prioritize and send the messages. The machines would have to be built using transistors in order to meet the size and power requirements, so in effect, the Army was paying to develop

transistorized computers upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...

. In spite of this, most established players ignored the Army's calls for the small machine. Sylvania's director of development speculated that the Army's terminology in the contract may have hidden the apparent wonderful opportunity. In the end,

RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...

and Sylvania entered bids, along with a number of smaller companies with unproven track records. Sylvania's bid was the lower of the "big two", and they won the contract in September 1956. The first experimental machine, retroactively known as MOBIDIC A, was delivered to Fort Monmouth in December 1959. By this time the Army had expressed increasing interest in the concept and had ordered four additional machines and associated software, including a COBOL compiler. The original contract for the experimental machine was for $1.6 million, but the new developments increased the total to between $20 and $30 million.Sokol, pg. 5 MOBIDIC B was supplied to the Army's Tactical Operations Center and featured dual CPUs for increased reliability. MOBIDIC A/B weighed about . MOBIDIC C was sent to Fort Huachuca as a

software Software is a set of computer programs and associated software documentation, documentation and data (computing), data. This is in contrast to Computer hardware, hardware, from which the system is built and which actually performs the work. ...

testing system. MOBIDIC D was ordered for the Army Security Agency in Europe, and MOBIDIC 7A was shipped to the 7th Army Stock Control Center in

Zweibrücken Zweibrücken (; french: Deux-Ponts, ; Palatinate German: ''Zweebrigge'', ; literally translated as "Two Bridges") is a town in Rhineland-Palatinate, Germany, on the Schwarzbach river. Name The name ''Zweibrücken'' means 'two bridges'; olde ...

, Germany. 7A's service entry was delayed due to the failure of the Army-supplied

tape drive A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and a long archival stability. ...

s, but Sylvania replaced these with off-the-shelf commercial units and the system went operational in January 1962,Sokol, pg. 4 the first off-shore deployment. MOBIDIC C/D/7A weighed about . The 7A unit was extremely successful in operation, cutting the time needed to order and deliver spare parts dramatically. Although Fieldata was developed for battlefield information, MOBIDIC was just as useful for other sorts of information as well, as the 7A machine demonstrated. It was so successful that the MOBIDIC D was diverted to the Army's 3922nd Ordnance Supply Control Agency in

Orléans Orléans (;"Orleans"
(US) and RAMAC 305 card system. By 1962, however, the Army had lost interest in Fieldata and canceled the project. The B machine was no longer needed for Fieldata software development, and in 1965 it was purchased by the

National Bureau of Standards The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...

for software development and research. The C, D, and 7A machines were later all moved to

Karlsruhe Karlsruhe ( , , ; South Franconian: ''Kallsruh'') is the third-largest city of the German state (''Land'') of Baden-Württemberg after its capital of Stuttgart and Mannheim, and the 22nd-largest city in the nation, with 308,436 inhabitants. ...

, Germany, where they operated in the supply role for years. MOBIDIC's success, independent of Fieldata's failure, led to additional Army contracts for the smaller AN/APQ-32 computers, which processed artillery radar data. The basic layout of the MOBIDIC system was also used for the AN/ASD-1 computer used on the

Boeing RC-135 The Boeing RC-135 is a family of large reconnaissance aircraft built by Boeing and modified by a number of companies, including General Dynamics, Lockheed, LTV, E-Systems, and L3 Technologies, and used by the United States Air Force and Royal ...

ELINT Signals intelligence (SIGINT) is intelligence-gathering by interception of '' signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication ...

aircraft, the PARADE and TIDEWATER projects, and its basic circuitry was used extensively in the development of the

IBM 7090 The IBM 7090 is a second-generation transistorized version of the earlier IBM 709 vacuum tube mainframe computer that was designed for "large-scale scientific and technological applications". The 7090 is the fourth member of the IBM 700/7000 se ...

for the BMEWS systems.Sokol, pg. 7 As Sylvania had hoped, commercial interest in a small, low-cost, robust computer system seemed widespread. MOBIDIC was adapted into the Sylvania 9400 that was marketed towards factory automation systems. Two systems were ordered, one by the Office of the Assistant Chief of Staff for Intelligence in the Pentagon, and another by

General Telephone GTE Corporation, formerly General Telephone & Electronics Corporation (1955–1982), was the largest independent telephone company in the United States during the days of the Bell System. The company operated from 1926, with roots tracing furt ...

in California. However, as the costs of trying to compete in the commercial computer market became clear, Sylvania decided to withdraw from the market, and General Telephone canceled their order. Both 9400's were built; General Telephone's intended delivery was used by Sylvania internally.Sokol, pg. 6

Description

MOBIDIC's design goal was the real time operation of its

input/output In computing, input/output (I/O, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system. Inputs are the signals ...

system. A typical use for MOBIDIC would be to collate all the messages flowing through an input to different tape outputs based on a field in the data. The tapes could then be removed and the messages printed on an offline printer. For instance, a large supply depot might have numerous warehouses for different sorts of materials; MOBIDIC could route incoming requests by examining the part number and then sending that message to a particular tape. All of the output on that tape would then be printed and sent to the associated warehouse. MOBIDIC replaced many manual steps; it performed the collation lookup, sorting the data, and collecting all the printed messages for delivery. MOBIDIC was a

36-bit 36-bit computers were popular in the early mainframe computer era from the 1950s through the early 1970s. Starting in the 1960s, but especially the 1970s, the introduction of 7-bit ASCII and 8-bit EBCDIC led to the move to machines using 8-bit ...

binary machine, a common word size for early computers. The system used 36-bit data throughout, but stored it as 40-bit values to add additional sign and parity bits, and two spares.Weik, pg. 0650 This allowed it to store the full range from -(1 - 2⁻³⁶) to +(1 - 2⁻³⁶). Machines were normally equipped with two parallel banks of

core memory Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the centra ...

with 4096 words each, but was expandable to seven banks maximum.Weik, pg. 0651 It could support up to 63

punch tape Five- and eight-hole punched paper tape Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop Punched tape or perforated paper tape is a form of data storage ...

input and output, as well as a

Flexowriter The Friden Flexowriter produced by the Friden Calculating Machine Company, was a teleprinter, a heavy-duty electric typewriter capable of being driven not only by a human typing, but also automatically by several methods, including direct atta ...

. One connection could also be dedicated to sending data to another MOBIDIC system. The tape drives used one of the spare bits in the 40-bit word as a STOP indicator. Most of the 52 instructions were in the one-address format, collecting into an accumulator, but a small number (load, move, etc.) were in two-address format. There were 15 arithmetic, eight transfer (memory), 17 logic, three sense and nine input-output instructions. An add required 16 microseconds, a multiply or divide 86, these slow times a side effect of its serial operation. MOBIDIC's CPU and I/O systems were housed in a 30-foot (10 meters) van. The machine required 29.76 kW of power, which was supplied from a second, smaller, van containing a generator set. Two other vans contained auxiliary EAM equipment and a repair shop. All four vans were backed up; two to a side, to a raised wooden platform with steps on one end. One of the concepts being; since this was the Cold War era than in case of enemy attack, everything could be moved instead of having to be abandoned and destroyed.Weik, pg. 0652 The dual-CPU MOBIDIC B (only one was produced) included three additional general instructions, as well as nine new instructions for supporting subroutines. The CPUs were independent but shared a single main memory consisting of 8,192 words of core. In a sample use, one of the CPUs would be used to import data, handing off data via shared memory to the second for output. Although the machine's speed was slower overall (adds were 42 μs), throughput could be greatly improved. If one of the machines failed, the program could be restarted on the remaining CPU, running both sides of the I/O task with reduced throughput.Weik, pg. 0654

References

Notes

Bibliography

* George Sokol
"MOBIDIC History"
Sylvania, 4 September 1967 * M.D. Abrams and R. Rosenthal, "On The Passing Of MOBIDIC-B", ''IEEE Computer'', Volume 6 Issue 3 (March 1973), pg. 10–18. doi:10.1109/C-M.1973.217033 * Martin Weik

https://hdl.handle.net/2027/mdp.39015023453221?urlappend=%3Bseq=660%3Bview=1up], A Third Survey of Domestic Electronic Digital Computing Systems, Ballistic Research Laboratories, Report No. 1115, March 1961, pg. 0650-0657

History

Description

References

Notes

Bibliography

Further reading