Tymshare Bitsaver

Tymshare, Inc. was a well-known timesharing service and third-party hardware maintenance company throughout its history and competed with companies such as Four Phase, Compuserve, and Digital Equipment Corporation (DEC, Digital). Tymshare developed or acquired innovative technologies, including data networking (Tymnet), electronic data interchange (EDI), credit card and payment processing (TTS, Western29), telecommunications provisioning (COEES), office automation (August, Augment) and database technology (Magnum). It was headquartered in Cupertino, California from 1964 to 1984. The computing platforms included the XDS 940 (Tymcom-IX), XDS Sigma 7, DEC PDP-10 models KA, KI, KL and KS (Tymcom-X/XX, Tenex, August, Tops-20), XKL Toad-1, IBM 360 & 370 (VM, MVS, GNOSIS) servers.

In 1984 Tymshare was acquired by McDonnell Douglas, restructured, split up and portions were resold, spun off, and merged with other companies from 1984 through 2004 when most of its legacy network was finally shut down. Islands of its network technology continued as part of EDI, at least into 2008. Rights to use technology developed by Tymshare is currently held by Boeing, British Telecom (BT), Verizon, and AT&T Inc. due to the acquisitions and mergers from 1984 through 2005.

Tymshare was founded in 1964 by Tom O’Rourke and Dave Schmidt as a time sharing company, selling computer time and software packages for users. It had two SDS/XDS 940 computers; access was via direct dial-up to the computers. In 1968, it purchased Dial Data, another time-sharing service bureau.

In 1968, Ann and Norm Hardy, Bill Frantz, Joe Rinde, and LaRoy Tymes developed the idea of using remote sites with minicomputers to communicate with the mainframes. The minicomputers would serve as the network's nodes, running a program called a "Supervisor" to route data. In November 1971, the first Tymnet Supervisor program became operational. Written in assembly code by LaRoy Tymes for the SDS 940, with architectural design contributions from Norman Hardy, the "Supervisor" was the beginning of the Tymnet network. The Varian 620i was also used for the TYMNET nodes. During those first years, Tymshare and its direct customers were the network's only users.

It soon became apparent that the SDS 940 could not keep up with the rapid growth of the network. In 1972, Joseph Rinde joined the Tymnet group and began porting the Supervisor code to the 32-bit Interdata 7/32, as the 8/32 was not yet ready. In 1973, the 8/32 became available, but the performance was disappointing and a crash-effort was made to develop a machine that could run Rinde's Supervisor. In 1974, a second, more efficient version of the Supervisor software became operational. The new Tymnet "Engine" software was used on both the Supervisor machines and on the nodes. After the migration to Interdata, they started developing Tymnet on the PDP-10. Tymshare sold a copy of the Tymnet network software to TRW, who created their own private network, TRWNET.

In the 1970s, Tymshare, which had used Digital Equipment's operating system TOPS-10 for its PDP-10s, began independent work on the OS for their systems, called it TYMCOM-X, and implemented a file system that supported random access, paging with working sets, and spawnable processes. The OS work was done by a group of eight people: Bill Weiher, Vance Socci, Allen Ginzburg, Karen Kolling, Art Atkinson, Gary Morgenthaler (founder of the company that produced IDRIS), Todd Corenson and Murray Bowles. Most Tymnet development was then done on TYMCOM-X.[3][4] Also in the 1970s, Tymshare acquired the Augmentation Research Center from SRI International. Tymes and Rinde then developed Tymnet II. Tymnet II ran in parallel with the original network, which continued to run on the Varian machines until it was phased out over a period of several years. Tymnet II's different method of constructing virtual circuits allowed for much better scalability.

In about 1979, Tymnet Inc. was spun off from Tymshare Inc. to continue administration and operation of the network. The network continued to grow, and customers who owned their own host computers and wanted access to them from remote sites became interested in connecting their computers to the network. This led to the foundation of Tymnet as a wholly owned subsidiary of Tymshare to run a public network as a common carrier within the United States. This allowed users to connect their host computers and terminals to the network, and use the computers from remote sites or sell time on their computers to other users of the network, with Tymnet charging them for the use of the network.

In 1984 Tymnet was bought by the McDonnell Douglas Corporation as part of the acquisition of Tymshare. The company was renamed McDonnell Douglas Tymshare, and began a major reorganization. A year later, McDonnell Douglas (MD) split Tymshare into several separate operating companies: MD Network Systems Company, MD Field Service Company, MD RCS, MD "xxx" and many more. (This is sometimes referred to the Alphabet Soup phase of the company). At this point, Tymnet had outlived its parent company Tymshare.

McDonnell Douglas acquired Microdata and created McDonnell Douglas Information Systems Group (MDISC), expecting to turn Microdata's desktop and server systems along with Tymshare's servers and Tymnet data network into a major player in the Information Services market. Microdata's systems were integrated into many parts of McDonnell Douglas, but Tymnet never was. MDC really did not seem to understand the telecommunications market. After five years, peace was breaking out in many places in the world and McDonnell Douglas sold off MDNSC and MDFSC at a profit for much needed cash.