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'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 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.

In early 1956 the Army Signal Corps at Fort Monmouth 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 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 was developing in their SAGE system, 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. 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 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.

MOBIDIC B was supplied to the Army's Tactical Operations Center and featured dual CPUs for increased reliability.

MOBIDIC A/B weighed about 12,000 pounds (6.0 short tons; 5.4 t).

MOBIDIC C was sent to Fort Huachuca as a software 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, Germany. 7A's service entry was delayed due to the failure of the Army-supplied tape drives, but Sylvania replaced these with off-the-shelf commercial units and the system went operational in January 1962, the first off-shore deployment.

MOBIDIC C/D/7A weighed about 7,000 pounds (3.5 short tons; 3.2 t).