![]() ![]() The minicomputers would serve as the network's nodes, running a program to route data. In 1968, Norm Hardy and LaRoy Tymes developed the idea of using remote sites with minicomputers to communicate with the mainframes. In 1968, it purchased Dial Data, another time-sharing service bureau. It had two SDS/XDS 940 computers access was via direct dial-up to the computers. Tymshare was founded in 1964 as a time sharing company, selling computer time and software packages for users. Data transfers were also possible via "auxiliary circuits". A Tymnet II node would set up its own "permuter tables", eliminating the need for the supervisor to keep copies of them, and had greater flexibility in handling its inter-node links. Tymnet II was developed to ameliorate the problems outlined above by off-loading some of the work-load from the supervisor and providing greater flexibility in the network by putting more intelligence into the node code. Tymnet II was developed in response to this challenge. As the network grew, the supervisor was in danger of being overloaded by the sheer number of nodes in the network, since the requirements for controlling the network took a great part of the supervisor's capacity. Tymnet later developed their own custom hardware, the Tymnet Engine, which contained both nodes and a supervisor running on one of those nodes. This did have the side effect of making data transfers quite difficult, as bytes from the file would be invisibly "translated" without specific intervention on the part of the user. The nodes handled character translation between various character sets, which were numerous at that time. In its original incarnation, the users connected to nodes built using Varian minicomputers, then entered commands that were passed to the supervisor which ran on a XDS 940 host.Ĭircuits were character oriented and the network was oriented towards interactive character-by-character full-duplex communications circuits. Unlike the TCP/IP protocol underlying the internet, Tymnet used a circuit switching layout which allowed the supervisors to be aware of every possible end-point. In its original implementation, the network supervisor contained most of the routing intelligence in the network. Tymnet was extensively used by large companies to provide dial-up services for their employees who were "on the road", as well as a gateway for users to connect to large online services such as CompuServe or The Source. For various technical reasons, the connection was not entirely "invisible", and sometimes required the user to enter arcane commands to make 8-bit clean connections work properly for file transfer. Once connected, data was passed to and from the user as if connected directly to a modem on the distant system. Users would dial into Tymnet and then interact with a simple command-line interface to establish a connection with a remote system. Tymnet offered local dial-up modem access in most cities in the United States and to a limited degree in Canada, which preferred its own DATAPAC service.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |