Here's another brief comment on the 'netCDF4 requirements' list,
The list includes chunking, but does not include compression.
I don't know if compression support is 'required' for netCDF4,
but it is supported by HDF5 and is a huge performance plus. We
know that NASA is extremely interested in compression.
I would include 'Compression and other filters' as an item, or
else add it to 'Chunking and compression'.
Another feature that should be considered for netCDF4 is
HDF5 'file drivers' other than MPI/IO. These are simple
to add to the API, require nothing of the netCDF profile,
and have significant benefits for some users.
Robert E. McGrath (HDF Java Team Leader)
National Center for Supercomputing Applications
University of Illinois, Urbana-Champaign
Champaign, Illinois 61820