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[netCDF #ZCE-849683]: clarification on large file support

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  • Subject: [netCDF #ZCE-849683]: clarification on large file support
  • Date: Mon, 12 Jul 2010 11:28:05 -0600
Fabio,

A little more clarification is needed to my last reply.  I said:

  Each variable in the file cannot exceed 4GB (not 2GB), in netCDF
  versions after 3.6.1, including the current netCDF 4.1.1. The actual
  maximum size of a variable on a 32-bit platform is (2^32 - 4) bytes.
  Part of the confusion is a documentation error here:

    
http://www.unidata.ucar.edu/software/netcdf/docs/netcdf.html#Classic-Limitations

  which I just discovered hasn't been updated since the size limit on a
  single variable was changed from 2GB (2^31 - 4) to 4GB (2^32 - 4) in
  versions since netCDF 3.6.1.

I was confused and the original documentation is correct.  The netCDF classic
format limits all but the last variable to 2GB in size.  It is the 64-bit offset
file format that permits all variables to be 4GB in size, and the last variable
to be even larger.  The netCDF-4/HDF5 format variant has no 4GB limits on the
size of any variable.  Sorry for the confusion!

--Russ



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



Ticket Details
===================
Ticket ID: ZCE-849683
Department: Support netCDF
Priority: Normal
Status: Closed