[AG-TECH] DPPT3 Failure - Conflict description and a fix

[Marty Hoag]

   For the past few months several of us have had some strange problems
with DPPT.  Our clients would fail for no apparent reason.  While the
last message is something like "nullpointer exception" we noticed that
up a few lines there is a message like 

   Caught JSDT exception: name in use

We had this problem on Monday during a virtual conference in genomics
and bioinformatics we were hub for.  Cindy Sievers at LANL mentioned
a couple times in the moo that her client was failing but then later
NDSU's failed and hers worked.  This pattern was consistent throughout
the day.  We had tried rebooting our display at one point even.
Kay Gunn was great in calling out slide changes but it wasn't so fun
for Cindy or Jim Senechal here who had to manually keep up (Jim 
was too far from the screen to read the numbers so we put binoculars
on our AG Node large event requirements list).

   It struck me that this sounded like some sort of resource conflict
between LANL and NDSU.  We looked at the agserv command window and
noticed the clients are identified by userid and host name.  We
saw that ours was coming in as  ag at agdisplay  .  Cindy had the same
combination!  Bob Olson has verified that this is indeed a problem
by checking the code.

   While I think we had the windows "DNS" stuff set up to use both a 
hostname and domain, we did NOT have that set up in the "Net ID" field 
of windows.  We think we have found a quick fix for this to avoid any
conflict.  There could be some strange implications if you are using
windows networking in some way but we made the change Monday evening
and ran all day Tuesday with LANL and NDSU coexisting and had no other
problems. 

   Here is the "quick fix" we used for W2K (we are at SP2 but I don't
think that should matter).  Please note that I'm not a windows
expert so my terminology might be wrong but I think I have our 
procedures down).  Use at your own risk (at least until independently
confirmed):  

1) Go do Start / Settings / Control Panel / System

2) Click on the Network Identification tab.  If your "Full computer
name" already is fully qualified then your machine should be
uniquely identified (at least for this problem).  If not go on...

3) Click on the Properties button.

4) The Computer Name is just the first element of the name.  To add a 
domain to qualify this click on the More... button.

5) For primary DNS suffix for this computer enter your domain.  E.g.
if the machine is agdisplay.foo.bar.edu then you'd add foo.bar.edu 
here.  

6) We UNCHECKED the "Change primary DNS suffix when domain membership
changes" because we didn't understand it and didn't want to do something
we didn't understand.

7) We OKed those and I think had to reboot.  Then when we connected to
our agserv we saw our Client ID as  ag at agdisplay.ndsu.nodak.edu .

   Since more sites are joining the AG and using more standardized 
software and documentation that probably explains why this seems to
be a more common problem (or maybe Cindy and NDSU are the only ones
who are "uncreative").

   Given work on a future replacement for DPPT (rppt) and the apparent
ease with fixing this (we probably need more than one site to try the
fix to confirm that) I'm not sure it is worth spending time rewriting 
DPPT at this point.  But that would be for others to decide.

   At least LANL and NDSU should be able to both be clients to the same
dppt server now.  ;-)  And this is yet another proof of the value of
collaboration and tools like the moo!  I owe Cindy a couple breakfast
burritos.  

   Marty