[daip] XAS using INET

[Patrick P. Murphy]

On Mon, 27 Nov 2000 16:03:33 -0600, Ben Jarvis <bjarvis at astro.umn.edu> said:

> The users tell me the AIPS cookbook says that AIPS will only allow one
> INET sockets based XAS session at a time, but allows 0-Z UNIX sockets.
> Is it still true that there is a limit of one INET session, 

Yes.

> and if so, why?

Because you can only have one process (effectively a daemon) sitting
listening to, e.g. port 5000 on any given host.  We had tried at various
times to retrofit multiple sockets to allow, say, 10 INET socket based
XAS's, but these schemes were invariably clunky and had other shortcomings
(most of which I don't remember now; this was many years ago) so they got
dropped. 

> We've been having problems involving one user starting AIPS without
> specifying tv=local:0,

I belive I put a hook in one of the startup scripts (in $AIPS_ROOT after
the install) that allows you to make "tv=local" the default:

  USEUNIXSOCK=NO

It's right below a cryptic comment warning about knowing what you're doing
in START_AIPS.  Changing this to YES instead of NO may do the trick.

> Other times /tmp fills up with XAS sockets which are never removed

This is a clear sign of users not shutting the AIPS system down cleanly.
There are several ways of doing this right (and relying on the window
manager to do it is unfortunately not one of them).  The easiest is to
have them use the verb KLEENEX to exit (instead of pressing control-d or
typing EXIT in the AIPS interpreter).  This will send out signals to shut
everything down, and *should* do the right cleanup of the sockets.

Another way is to (a) press <ESCAPE> in the XAS window, (b) press
<CONTROL-C> in the message server window, (c) use <CTRL-LEFT-MOUSE> in the
tekserver xterm and use the "quit" menu item, and (d) type EXIT in AIPS.
You can see why people use KLEENEX instead.

Hope this helps.
				- Pat

-- 
  Patrick P. Murphy, Ph.D.            Division Head, Charlottesville Computing
  (804) 296-0372, 296-0236                National Radio Astronomy Observatory
  Home: http://www.chien-noir.com/      Work: http://www.cv.nrao.edu/~pmurphy/
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