Rapid Prototyping of Protocols from LOTOS Specifications

A new tool for generating implementation prototypes of communication protocols and concurrent systems specified using the ISO LOTOS language is presented in this paper. A brief introduction to LOTOS and a discussion of the main problems related to the efficient execution of specifications written in LOTOS are presented first. The design and implementation of the tool are then considered: LOTOS specifications are analysed and translated into C functions which are executed by co-operating processes in the Unix environment. The set of LOTOS process definitions is first translated into a suitable number of extended finite-state machines (EFSMs). The method proposed allows the problem of deriving unbounded EFSMs to be circumvented and a sort of control on the process number/size trade-off to be obtained at the same time. The problem of implementing the LOTOS multi-way rendezvous mechanism for process synchronization is solved by using an algorithm based on message-passing techniques. An example of prototype derivation is also described, showing the form of C code generated by translating a simple specification. Finally, some performance figures are presented.