The server network generator (SNG): a CASE tool for distributed cooperative processing

The Server Network Generator (SNG) is a CASE tool that employs a problem solver's ability to represent an application as an ordinary block diagram, a graphical specification of its macroscopic structure. This functional decomposition provides a natural mechanism for subdividing the application into processing tasks that can be distributed across a computing network. Each "server" is a software process that assumes the role of one block in the diagram, performing one processing task, employing interprocess communication as indicated graphically. This approach differs from related research in its use of a functional decomposition in the application context, and its use of graphical programming of the application's macroscopic structure. A distributed network of IBM 7437 VM/SP Technical Workstations are shown as a powerful platform for problem solving, using the SNG as a CASE tool. Distributed computing models based upon networks of microprocessors have long been proposed as an alternative to centralized mainframe computing. The 7437 provides a genuine VM/370 computing environment, so that this approach to distributed computing allows large mainframe systems to be the most powerful nodes in the network, rather than attempting to replace them. A recently completed auxiliary processor is presented that was required to support interprocess communication via the shared-variable interface between virtual machines on different hosts.