Path: utzoo!attcan!uunet!zephyr.ens.tek.com!tektronix!nosun!qiclab!m2xenix!quagga!ucthpx!uctcs!gram From: gram@uctcs.uucp (Graham Wheeler) Newsgroups: comp.protocols.iso Subject: Re: Formal Specification in OSI Keywords: FDT, Estelle and LOTOS. Message-ID: <802@ucthpx.UUCP> Date: 4 Oct 90 06:54:27 GMT References: <1262@umvlsi.ecs.umass.edu> Sender: news@ucthpx.UUCP Reply-To: gram@staff.UUCP (Graham Wheeler) Organization: Dept. of Computer Science, University of Cape Town Lines: 21 Just a brief comment - Estelle (Extended State Transition Language) is a Pascal superset allowing asynchronous concurrent execution of FSM-based processes communicating via message passing. It is an implementation-oriented FDT. Lotos is based on Petri-nets, as far as I can recall. It is much more `academic' than Estelle. I heard (second-hand) that Dave Parnas said (at the 2nd International Conference on FDT's in Canada late last year) that Lotos was popular because it had a lot of scope for making little extensions and modifications and getting publications as a result. Real protocol developers use Estelle (if they use any FDT). Just my two cents worth... Graham Wheeler | "Don't bother me, Data Network Architectures Lab| I'm reading a `Crisis'!" Dept. of Computer Science | Internet: University of Cape Town | BANG: <...uunet!ddsw1!olsa99!uctcs!gram>