Using PS-nets for analysis of parallel processes interaction in application server

Application servers (ASs) are actively used by various companies as a basis of distributed systems supporting remote user access to some application functions. Developing multi-user software seems a non-trivial problem for the necessity of providing parallel process interaction. The geoinformation AS (Markov and Ostrast, 1999) is of the following structure of process interaction. For each user connected, a session is created as a process. Each session has a time limit, after expiration of which the unused session is deleted. The main process carries out process creation/deletion and processing of the global session list. A lump of processes and the necessity of their synchronization have required modeling AS software for validating its correctness. The formalism of PS-nets has been used by the authors as the model of representing the parallel processes (Markov et al., 1997). With its help, the problems of validating AS software correctness have been analyzed.