The virtual circuit service is a common feature of local area communications networks (LACNs). This feature provides the user of a network with the functionality of direct connectivity to any host computer on the network. At the University of California, San Francisco Hospital a microcomputer based LACN using fiberoptic communications media has been in use for over two years. We have limited our use of the virtual circuit function for direct user terminal connectivity to situations involving only the most sophisticated users, such as programmers and analysts. For functions involving typical hospital users such as physicians and nurses, we chose a more "user friendly" approach by interposing host application software between the user and other host computers on the network.
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