A tool for the animation of message interactions between
concurrent processes is presented. Each message interaction,
such as a send or receive, has a corresponding static graphical
representation. The interactions among the processes of an executing
distributed computation are represented by an animated sequence of
these static images.
This graphical monitoring tool, called Mona, is part of a
distributed software prototyping environment, called Jade. The Jade
environment supports the implementation of distributed programs
written in ADA, C, Lisp, Prolog, and Simula. The execution of these
multilingual programs can be distributed over a loosely coupled
network of Vax/Unix systems and microcomputer workstations.
Preliminary experience using Mona to develop distributed programs is
also reported. In particular, the application of Mona to the debugging
of a distributed implementation of a workstation virtual terminal window
system is described. We also discuss the advantages of graphical
monitoring over more traditional approaches, i.e. textual tracing.