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Titre :

Beyond Tymshare - MDC, BT, MCI, Concert, Worldcom


Carl Baltrunas


August 4, 2006


A brief timeline of the companies that controlled the Tymshare legacy.

Tymshare was acquired by McDonnell Douglas sometime around April 1984. MDC renamed the company McDonnell Douglas Tymshare.

  • Under MDC's stewardship, parts of the company were integrated, parts were dismantled and other parts were held as assets later sold for a profit.
  • They created MDC-ISG to sell and market their computing and networking products.

As peace was breaking out all over the world in the late 1980s, McDonnell Douglas needed cash.

  • They spun off MDCFSCO (MDC Field Service Company) to a startup lead by Bert Novak named Novadyne.
  • MDC sold MDCNSC (Network Systems Company) and part the Computer Operations in Fremont, Cupertino and Valley Forge to British Telecom. The sale was announced on July 31st, 1989 and all transfers into or out of MDCFSCO and MDCNSC were frozen. The sale was finalized on November 17th, 1989, and BT renamed MDNSC to BT Tymnet.

A year or two later BT Tymnet was renamed BT North America, and yet again to BTNA. When BT purchased the Tymnet property, US telecommunications laws required BT to obtain restricted licenses to continue to run Tymnet. As the laws changed, BT wanted to expand, and obtain a footing in the USA. They looked to MCI, first to buy, but now allowed, and then to create an alliance. Called "The Deal of the Century", BT "sold" the US-based portion of the original BT Tymnet properties to MCI, kept the rest of Tymnet worldwide as part of BT, and formed a new company, to be named later, called NewCo, to handle all international traffic. NewCo was eventually named Concert which was a partnership that allowed US based MCI, and UK based BT to work together "in Concert". The deal was finalized, and MCI took over the US based properties on February 1st, 1994.

MCI took awhile to integrate Tymnet into its fold. Although they knew how to run a long distance telephone carrier, and lease private telecommunications lines to companies, owning the assets to run and manage a complete end-to-end data network was a little different. Two things rang true the entire time that MCI was at the helm. Their motto seemed to be, "Ready, Fire, Aim", and every month there was a reorganizaion somewhere in MCI. We joked that there was a reorganization, it took two weeks to have personnel move into new quarters with the rest of their new groups, and two weeks later there was another reorganization.

By 1997, telecommunication laws changed and BT was looking to actually purchase MCI. BT and MCI were the 4th and 6th largest telecom companies world-wide, and by merging they would become the 3rd largest immediately behind the German Bundespost and AT&T. The deal was set. Stockholders in both companies had approved the merger. BT higher-ups thought that if they could renegotiate a slightly lower price tag, they would be able to put that saved money into the dividends they paid out each year. That waver was seen by Worldcom as a hole in an otherwise iron-clad deal. BTs deal would cash-out any stock held in MCI. Worldcom offered a nearly identical deal, but with a stock-swap instead of a cash-out which meant no capital gains tax for many many people. MCI took the Worldcom deal, and the sale became final on September 15th 1998. Both MCI and worldcom had to divest certain product lines to insure they did not hold monopoly power over the internet infrastructure or ISP services. One month after the sale was final, BT and MCI dissolved their alliance and MCI withdrew their stake in Concert.

BT retained intellectual property rights over the Tymnet technology, but Worldcom was given a right to use it. This initiated the project to plan and implement the separation of physical assets each party owned in Tymnet, and included each company taking their portion of clients with them. Worldcom split it's holdings into a few separate units, with Tymnet being part of MCI Worldcom. BT found another partner in Concert and went 50-50 with AT&T. Due to the rivalry between AT&T and MCI, MCI Worldcom management dragged it's feet and refused to co-operate with BT and Concert on many projects, including the network split. Due to this and other obstacles, the split project was put on hold several times and was finally abandoned when Worldcom shut down its portion of the network on April 1st, 2003. Much of the split had been completed by then. Concert, which took total control of BTs Tymnet assets in 1999 replicated all the components needed to run the supervisors, accounting collection, and all the administration and took over running the now un-split network on April 1st.

On October 31st 2002, BT and AT&T broke their alliance in Concert. This gave AT&T all the far east and pacific holdings, many of which were originally part of Tymshare and Tymnet. A small west-coast portion (my group) and eastern USA and qurope were retained by BT. BT merged it's Concert properties and BTNA into BT Americas. BT and BT Americas continued the second half of the split project which was to migrate their Tymnet clients to other IP and x.25 product lines. The last active Tymnet customer, the Germany-based Amadeus, a hotel and travel registration service, with clients that used Tymnet from Malasia, was finally migrated in February 2004. The remaining former Concert employees that supported and maintained Tymnet were let go at the end of January 2004. Tymnet was finally shut down in late February by disabling the links from the last 2 active supervisors to the network, thus making it impossible for any new circuits to be created.

However, one small part of Tymnet still survives. The EDI group, once also called Payment Systems, were running Tandem computers with a non-standard x.25 configuration. Tymnet know how to communicate with the Tandem hosts, buts the Cisco and other off-the-shelf products did not. Ron Vivier and Jerry Lucas conceived and implemented the idea of having a stand-alone Tymnet node that could build internal circuits between slots on that node. Node code was modified to not require a supervisor connection, and to be able to build those internal slot to slot circuits based on host numbers in each slot. All nodes in this configuration were loaded via the TTY port on the node and their connections to Tymnet were severed. Tymnet technology lives on in one-node networks allowing the EDI product to continue, at least until those clients are moved to other services.

As of this writing, I believe the EDI connections are still up. When I find out they are gone, I will update this entry with the relevent information.