The State of PEP ? Bernd

The PEP tool can be considered to be one of the most widely distributed Petri net based tools. A continuously increasing functionality and an adequate graphical user interface may have been good reasons for its acceptance. Currently the tool contains approximately 500,000 lines of source code, and supports (to the best of our knowledge) the widest variety of input formalisms and veriication methods of all veriication tools. We brieey review the most recent developments. Ftp-able versions of the tool and PEP related papers are available via 1 New Petri net generators One of the key features of the PEP tool 3] is that simulation, analysis and veriication of diierent input formalisms { SDL (Speciication Description Language 6]) systems, { parallel programs written in B(PN) 2 4], { parallel nite automata (PFA) 11], { process algebra terms expressed in the PBC 1], { high-level (HL) Petri nets in the M-nets algebra 2], and { low-level (LL) Petri nets 1] are based on Petri net theory. PEP's existing transformers between diierent formalisms (PFA) B(PN) 2 , B(PN) 2) PBC, PBC) LL net, B(PN) 2) HL net, and HL net) LL net) were accomplished with two new compilers. An HL Petri net semantics of SDL 10] was implemented. In particular, dynamic creation as well as termination of processes and (also recursive) procedures are covered. Its integration in PEP supports almost the same simulation, analysis and veriication methods as there are available for B(PN) 2 programs: { An SDL simulation may be triggered by a Petri net simulation. { Standard analyses, such as deadlock detection are possible. { CTL and LTL properties of SDL speciications may be checked. The user may, e.g., ask whether there exists an instance of a certain process Sender, such that whenever this instance is in state wait while its input queue is non-empty, then it may reach a state send while its variable X has value 3: ? PEP has been a joint project between thèUniversitt at Hildesheim', thèCarl-von-Ossietzky Universitt at Oldenburg' and thèHumboldt-Universitt at zu Berlin' which has been nanced by the DFG (German Research Foundation).