Re: 971208: 500MB file

>To: address@hidden
>From: John Caron <address@hidden>
>Subject: 500MB file
>Organization: .
>Keywords: 199712081818.LAA05231

Hi John,

> I have a 500MB file, which ncdump is hanging on when I say:
>       ncdump -v time <name>
> 
> Is there any problems with files of that size?

No problem that I know of.  Files larger than 2 Gbytes may cause a
problem because of 31-bit offsets.

> Any way to confirm possible corruption?

There's no checksum or similar redundancy in netCDF files, so corruption
may not be detectable.

Can you just do

        ncdump <name> > /dev/null

to verify that ncdump doesn't hang when you don't specify the variable
"time"?  If you have enough disk space, can you verify that ncdump
works on the whole file without specifying the variable "time"?

Alternatively, you might try 

        ncdump <name> | grep "}"

to verify whether ncdump hangs in this case.

If you could make the file available for FTP, we could try to reproduce
and diagnose the problem.

--Russ

_____________________________________________________________________

Russ Rew                                         UCAR Unidata Program
address@hidden                     http://www.unidata.ucar.edu