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Re: "Remik Ziemlinski": NetCDF4 1.0

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  • Subject: Re: "Remik Ziemlinski": NetCDF4 1.0
  • Date: 13 Aug 2004 09:58:32 -0600
"Remik Ziemlinski" <address@hidden> writes:

> Thanks for the reply Ed.  Our current dilemma is w.r.t. the 2 GB
> record limit, i.e. the pointer offset of the last record variable must
> be under 2^31.  Does NC_64BIT_OFFSET address this issue?  We'd be very
> happy with just that!
> 
> Remik

Yes, it does. I've appended a description of the new size limitations
from the soon-to-be-released next version of the netCDF documentation.

"No fixed-size variable can require more than 2^32 - 4 bytes (i.e. 4GB
- 4 bytes) of storage for its data, unless it is the last fixed-size
variable and there are no record variables. When there are no record
variables, the last fixed-size variable can be any size supported by
the file system, e.g. terabytes.

Therefore, a 64-bit offaset format netCDF file can have any number of
fixed sized variables, each under 4GB in size. If there are no record
variables in the file the last fixed variable can be any size.
 
No record variable can require more than 2^32 - 4 bytes of storage for
each record's worth of data, unless it is the last record variable.

A 64-bit offset format netCDF file can have any number of records, of
any number of variables, as long as the size of the data for one
record or one variable is less than 4 GB. As with fixed size
variables, the last record variable can be any size."