What is the relationship between Ptolemy and Metropolis?
Ptolemy (http://ptolemy.eecs.berkeley.edu) and Metropolis (http://embedded.eecs.berkeley.edu/metropolis/) are separate research projects at Berkeley, albeit ones with considerable cross-influences. Ptolemy is headed by Edward Lee, while Metropolis is headed by Alberto Sangiovanni-Vincentelli. A key principle in Metropolis is its “meta model,” which in the terminology of the Ptolemy project we would call its “abstract semantics.” In Metropolis, models consist of processes, with their own thread of control, that communicate through ports and “media.” The media are roughly equivalent to Ptolemy Receivers; they define the communication semantics between components. The abstract semantics of Metropolis, is an abstraction of the model of computation that appears in the Ptolemy PN and CSP domains. It is an abstraction because in Metropolis, the communication semantics is not defined, whereas in PN and CSP, it is (in two different ways). Metropolis model builders construct the media that proce
