Apps Messaging - Semantics of a Message

[Mike Fitzpatrick]

> I think I get the idea, but this is really rather strange.  We would
> like to display an image (for example), so we broadcast a display
> request to anyone who might be out there, and they all on their own
> display the image, or do some other random thing which is similar?

Of course it wouldn't be a random thing, we'd assume the developer
would read the spec's definition of the 'display' class and do something
along those lines in the context of his/her app.  But how is sending a
display request to some anonymous process for handling that much
different than IRAF using the image display without knowing specifically
whether it's XImtool or DS9 on the other end.  Just as the only require-
ment is an understanding of the IIS protocol, in the msg  system the
only requirement is an understanding of a display.fits message (and
implicit agreement that it does "the right thing").

-Mike