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Description:
Beautifully engraved unissued certificate from the Tymshare, Inc. This historic document was printed by the American Banknote Company in 1978 and has an ornate border around it with a vignette of a woman infront of a city skyline. This item has the printed signatures of the Company’s President and Secretary. This is the first time we have had this certificate for sale.
Certificate Vignette TYMNET A United States-wide commercial computer network, created by Tymshare, Inc. some time before 1970, and used for remote login and file transfer. In its original implementation, it was made up of a number of fairly simple circuit-oriented nodes, whose circuits were created by one central network supervisor writing into the appropriate nodes' "permuter tables". The supervisors also performed login validations as well as circuit management. Circuits were character oriented and the network was oriented towards interactive character-by-character full-duplex communications circuits. There was a clever scheme to switch the echoing function between the local node and the host based on whether or not a special character had been typed by the user. Data transfers were also possible via "auxiliary circuits". The network had more than one supervisor running, but only one was active, the others being put to sleep with "sleeping pill" messages. If the active supervisor went down, all the others would wake up and battle for control of the network. After the battle, the supervisor with the highest pre-set priority would dominate, and the network would then again be controlled by only one supervisor. (During the takeover battle, the net consisted of subsets of itself across which new circuits could not be built). Existing circuits were not affected by supervisor switches. Tymshare, Inc. originally wrote and implemented TYMNET to provide nationwide access for their time-sharing customers. When Tymshare started using Interdata 8/32 minicomputers as nodes they started developing TYMNET on PDP-10. The Tymshare hosts (which ran customer code) were SDS 940, XDS 940, DEC PDP-10, and eventually IBM 370 computers. The switches were originally: Varian Data Machines 620 and Interdata 8/32. PDP-10s supported (and still do in 1999) cross-platform development and billing. Tymshare sold the TYMNET network software to TRW, who created their own private network (which was not called TYMNET). In about 1979, TYMNET Inc. was spun off from Tymshare, Inc. to continue administration and development of the network. TYMNET was the largest commercial network in the United States in its heyday, with nodes in every major US city and a few overseas as well. Tymshare acquired a French subsidiary, SLIGOS, and had TYMNET nodes in Paris, France. Tymshare was purchased by McDonnell Douglas in 1984 who renamed the Tymnet group to the McDonnell Douglas Network Systems Company. Tymshare's hardware personnel became the McDonnell Douglass Field Service Company. McDonnell Douglas sold the networking part of the company to British Telecom, who named it BT Tymnet and then to BT North America. BT subsequently sold the networking group to MCI and formed a partnership of MCI + BT called Concert. BT was planning a merger with MCI but WorldCom made a better offer. MCI became MCI Worldcomm.
| Status: For Sale |
Reference#: tymshareinc |
| Condition:
See Description |
Year:
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