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[McIDAS #ABG-678484]: netCDF and McIDAS

Hi Brice,

Some general comments:

It is hard for me to comment in any detail without being able to see
and compare the netCDF files created on your 32-bit and 64-bit
systems.  Off of the top of my head, I would say that there can
be differences in files created on the two systems, but I really
need to talk to the netCDF folks here to make sure.

Second, I have always viewed the netCDF ADDE servers with some suspicion.
I came to this feeling quite some time ago while code diving while
trying to troubleshoot a problem I was experiencing.  I have not looked
at the code in a LONG time, so things may have changed since that one

Just so I understand what you are seeing: are you saying that you
can use the McIDAS ADDE netCDF server for netCDF file(s) generated
on 32-bit systems, but you can not use the file(s) generated on
64-bit systems?  If the answer is yes, perhaps the difference is
that the netCDF files generated on the 64-bit system have large file
support built-in while those created on the 32-bit system do not.
If this is the case, it means that the netCDF library built/used
in McIDAS would need to be built with large file support in order
to handle the file(s) created on the 64-bit system.

> We got around to coming back to this issue and ran smack into a brick wall.
> Worse it's toward the end of another big project and this function is a key
> piece, so now I'm on the hook.  Looking for information more than actual
> code digging.  A new piece of information that surfaced was that when we
> generated netCDF files from the same BUFR point files on the 32 and 64-bit
> machines and ran ncdump on them, a comparison of the ncdump output showed
> only some rounding differences with the exception of the header info.
> Ncdump had no problems displaying all of the data in the files.  What I
> would like from you is validation (or not) of my perception that this
> information shows we are creating the netCDF files correctly on the 64-bit
> system, but that ncdfks is having issues.  We found that the 'hacked'
> version of ncdfks was not required to read the files on the 32-bit systems;
> we are using the McIDAS core ncdfks.  If this theory is correct, and SSEC
> tells me they have almost no one with any netCDF experience any more at
> least with the older McIDAS-X platforms so it's possible, then I can leave
> the transition software alone and focus on the server solution or
> eliminating the netCDF part completely and dumping it to some other
> structure.
> Am I missing something here, do you think?  BTW we did make sure of all the
> linking issues before this.

The only thing that comes to mind that "feels sorta right" is the issue
with large file support.  I could be completely off base, of course;
getting a couple of files created from the same data on the different
platforms should go a long way towards affirming/negating my musing.


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Ticket Details
Ticket ID: ABG-678484
Department: Support McIDAS
Priority: Normal
Status: Open

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