The Pep Tool Pep Has Been Implemented on Solaris 2.x, Sun Os 4.1.x and Linux. Ftp-able Ver- 2 Editing and Simulation Component

The PEP tool embeds sophisticated programming and veriication components in a user-friendly graphical interface. The basic idea is that the programming component allows the user to design concurrent algorithms in an imperative language, and that the PEP system then generates Petri nets from such programs in order to use Petri net theory for simulation and veriication purposes. A key feature is exibility; its modular design eases the task of adding new interfaces to other veriication packages, such as`INA', `PROD' or`SMV'. 1 System overview The PEP 1 tool is a Programming Environment based on Petri Nets 5]. The main phases of the development of parallel systems (modelling, simulation, analysis and veriication) are supported. From an abstract point of view the tool consists of the following three components (see Fig. 1): 1. The editing and simulation component contains editors and simulators for parallel systems from which Petri nets can be generated automatically using the diierent compilers integrated in this component. 2. The formula component ooers the possibility to enter formulae which can either refer to a parallel program or a net. Furthermore, program formulae can be transformed into net formulae 14]. 3. The veriication component consisted of a model checker 11,15] based on the nite preex of the branching process 20,10]. Interfaces to other veriication packages, likèINA' 21], `PROD' 24] or`SMV' 8], have been added recently in order to ooer as many diierent veriication methods as possible and to support stronger logics. The editing and simulation component of the PEP system has grown continuously. Corresponding to the main intention of the tool { i.e. to use Petri net theory in order to provide program veriication { a program editor and a net editor have been the starting point. With the rst version of PEP it was possible to edit parallel algorithms expressed in B(PN) 2 , an imperative / predicative programming language. B(PN) 2 1 PEP is a joint project between thèUniversitt at Hildesheim' and thèHumboldt