Writing large files from pnetcdf on IBM
Robert Latham
robl at mcs.anl.gov
Tue Nov 28 13:33:06 CST 2006
On Tue, Nov 28, 2006 at 12:20:06PM -0700, John Michalakes wrote:
> If I keep the NF_64BIT_OFFSET flag and write the file that is < 2GB, I get:
>
> 0000000 4344 4601 0000 0001 0000 000a 0000 0008
> 0000020 0000 0004 5469 6d65 0000 0000 0000 000a
> 0000040 4461 7465 5374 724c 656e 0000 0000 0013
>
> Which is correct, but it's still CDF1, even though the flag is set in the
> NFMPI_CREATE.
>
> BTW, if I use serial NetCDF to write the >2GB file with NF_64BIT_OFFSET:
>
> 0000000 4344 4602 0000 0000 0000 000a 0000 0008
> 0000020 0000 0004 5469 6d65 0000 0000 0000 000a
> 0000040 4461 7465 5374 724c 656e 0000 0000 0013
>
> but it is *very* slow.
>
> Without NF_64BIT_OFFSET, serial NetCDF fails trying to open the file.
Ok, this is good information, especially that the NF_64BIT_OFFSET flag
is not creating CDF-2 files. I will have to dig into this. I'll send
an update when I know more...
==rob
--
Rob Latham
Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA B29D F333 664A 4280 315B
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