Abstract

A method to preserve system resources during the execution of distributed application programs in an SNA type data processing network that supports program to program communication between an Intelligent Work Station (IWS) and a host processor in accordance with SNA Logical Unit 6.2 protocols when a Virtual Machine Pool Manager exists at the host processor and functions to,(1) create a pool of virtual machines at the host processor that are brought to a run ready state prior to any program to program communciation,(2) dynamically assign an idle run ready virtual machine to process each request from the IWS involving one application program so that sequential requests from the one program are assigned to different ones of the idle virtual machines and run concurrently, and3) provide a Pool Manager Data Structure for use by the Pool Manager during the step of dynamically assigning the idle run ready virtual machines in the pool. The Operating System for the IWS attaches a process identifier (PRID) and a thread identifier (THRID) to predefined segments of the resident application program that include LU 6.2 type conversation requests. The ID are transmitted to the host at the time a request is transmitted to permit the Virtual Machine Pool Manager to decide, based on the transmitted ID and previously received IDs whether to assign the request to an active or idle virtual machine in the pool. If the ID is the same as a segment being run on an active machine, the request are assigned to the same machine. If the transmitted THRID is different, the request is assigned to an idle machine in the pool. Therefore, predefined segments can be executed concurrently on different assigned virtual machines at the host only when the application program segments have been assigned different THRIDs by the terminal operating system.

Other References

• IBM, "An Introduction to Advanced Program-to-Program Communication (APPC)", Document No. GG24-1584-1, Nov. 1986, Int. Tech. Support Center, Raleigh, North Carolin