3 Related Work

In the distributed systems world, many works formalizing the objects behaviour exist. These works can be separated into two categories :

• the FDTs (Formal Description Techniques) ;
• the extensions of existing distributed system specification languages.

An FDT is an existing language which is being used in other domains. Specifying object behaviours with a FDT language comes to impose the FDT language properties such as the typing of data on the application specifications ([Kel95], [Fes94]). Some FDT examples are VDM, LOTOS, Z, etc [ISO94].

In some distributed system specification languages, the object behaviours are defined informally (cf. section 1). In these languages, the object behaviours are explicitly identified in specifications. Some works replace these informal behaviours by formal descriptions. In contrast to FDTs, no constraints on typing of data are defined, since the extended specification languages do not constraint the languages extended. Some extended languages are $\mbox{GDMO}^+$ [GDM97], GDMO/CRS [Fes94], Q-GDMO-GRM [TIN95], etc.

None of the above mentionned solutions define animated specifications such as the use of explicit determinism. Furthermore, our work is to apply explicit determinism on Q-GDMO-GRM. Q-GDMO-GRM allows to the use of any logical formalism to specify object behaviours. Our practical work is to simulate Q-GDMO-GRM specifications extended with explicit determinism.