[seek-dev] Re: [kepler-dev] Re: [seek-kr-sms] UI

[Edward A Lee]

At 09:04 AM 6/11/2004 -0500, Rod Spears wrote:
>In a perfect world of time and budgets it would be nice to create a tool 
>that has standalone Modeling and Analysis Definition Language, then a core 
>standalone analysis/simulation engine, and lastly a set of GUI tools that 
>assist the scientists in creating the models and monitoring the execution. 
>Notice how the GUI came last? The GUI needs to be born out of the 
>underlying technology instead of defining it.

If I can chime in...

I believe that current work in Kepler _is_ that of creating
a Modeling and Analysis Definition Language.  The fact that it has
a visual syntax does not make it any less a language. In fact, I would
argue that when one is thinking about concurrent and distributed models,
focusing on a visual syntax can be liberating, because it helps us
break out of the procedural mode that prevails in textual languages.

That said, I think we haven't done enough free thinking about
what the semantics of this language can be...  E.g., it may not
always make sense to wrap web services in a process network actor,
since for some web services, the metaphor of streaming data
through the web service may not make sense...
Web services are typically defined in terms of functions
that are invoked remotely...

In view of this, we are working on a mechanism that is intended
to parallel the actor package and its domains, which are all oriented
around streaming data through components. For lack of a better
term, we are calling this the "component" package, because it
bears a basic similarity with standard software component
architectures like CORBA and DCOM, but our intent is to
provide domains built on this "component" package that
provide simple and understandable concurrency models.
We have been inspired by nesC (a language used for programming
sensor nodes in sensor networks) and Click (a language used
for defining software-based network routers).

Edward


------------
Edward A. Lee, Professor
518 Cory Hall, UC Berkeley, Berkeley, CA 94720
phone: 510-642-0455, fax: 510-642-2739
eal at eecs.Berkeley.EDU, http://ptolemy.eecs.berkeley.edu/~eal