[McIDAS #WPR-272383]: DMRAOB - Program terminated, segmentation violation

Hi Mike,

re:
> Wanting to try the simplest thing first, I deleted those MD files as you
> suggested and that did the trick.  They filled in right away after starting
> LDM back up, and HODO has been working fine ever since.  So thank you for
> that suggestion.

Excellent!

re:
> It's very rare, only happened maybe a few times in the last several years.
> But to clarify, the 'exec "xcd_run MONITOR"' line in our ldmd.conf starts
> up the process, and then doing a 'ps ax | grep xcd' shows startxcd.k
> and xcd_run MONITOR processes.  Once in a great while one of those dies,
> and restarting LDM will start it back up again.  That's all I was referring
> to above.  I don't think it has anything to do directly with LDM, just the
> act of invoking that exec entry.

This is interesting since we have never (to the best of my recollection) seen
startxcd.k exit.

re: rebuild and reinstall the McIDAS-XCD decoders
> I didn't attempt this.  Truthfully I'm probably a version or two behind on
> this server so a full install will probably be coming in the months ahead.

Yes, there have been a number of changes to the XCD portion of the Unidata
McIDAS-X distribution over the past several years.

re:
> Wasn't sure if there was a more surgical approach that would rebuild just
> dmraob.k; I guess there isn't so that's good to know.

One or more of the output MD files must have gotten damaged.

re: examine a core file to see where an executable "went wrong"

> This is news to me.  I don't see any core.xxx files sitting anyplace
> obvious, not sure where they should reside if I had them.

First, the session in which you are running the LDM and XCD decoders
would need to have dumping core files enabled.  If that is done, the
core files would typically be written to the HOME directory of the user
running the LDM, but this can be configured, so where things would
actually be written might be different.

re:
> I also don't
> know how I would enable core dumping.  I went back and looked at the
> install instructions but I didn't see anything about this.

Enabling dumping of a core file is typically a Unix/Linux thing, but
McIDAS can turn off core dumping if it is enabled.  The following
snippit from 'xcd_run" explains what to do:

# NB: Change POKEd value to 0 _IF_ you want XCD decoders to dump core files
mcenv << EOF
ucu.k POKE 142 1
exec startxcd.k
EOF

re:
> For reference,
> here's the guide I'm going off of:
> https://www.unidata.ucar.edu/software/mcidas/current/users_guide/InstallingMcIDAS-XonUnixorMacOSXWorkstations.html

I don't recall every documenting how to turn on core dumping in
the online material.  It is there, however, in the 'xcd_run' source.

re: Questions:
> >
> > - are you using a standard McIDAS installation?
> >
> 
> I thought I was.  But I've never come across anything pertaining to core
> dumping before so now I'm not entirely sure.

Users rarely would turn on core dumping in McIDAS.

re:
> - what OS are your XCD decoders running?
> >
> 
> Ubuntu 18.04.3 LTS

Hmm... You are running in an environment which we have no experience.
I kinda figured that it was the case that you are running in an Ubuntu
environment.  It is interesting to hear that it is v18.04.3 LTS.  I
intend to setup this environment when I re-purpose my old Windows 7
laptop to a Linux machine just so I can get first hand experience in
this environment.

re:
> Thanks, Tom, you've saved my hide once again!

No worries.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: WPR-272383
Department: Support McIDAS
Priority: Normal
Status: Closed
===================
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