[#XJU-559475]: Re: Fwd: netcdf4 vs. netcdf3

Hi Arlindo,

The current netCDF-4/HDF5 format is based on an alpha release of HDF5, because 
that's all that's available until the HDF5-beta release comes out that has the 
format chages and API additions needed to support shared dimensions and access 
to Group objects in creation order.  I agree with the HDF5 people that it would 
not be a good idea to assume you could later read data trough the netCDF-4 
library that is written with the netCDF-4 alpha release based on an HDF5 alpha 
release.

The latest word we hear is that the HDF5-1.8-beta will be available in about 6 
weeks, and we will then work hard to get out a netCDF-4.0-beta within six weeks 
of that release.  Once a netCDF-4 beta release is available, we will commit to 
supporting the format, which means all future versions of netCDF will be able 
to read data written with that release.  

With some extra work we could also support the current alpha format that 
includes HDF5 artifacts to emulate shared dimensions and creation order, but we 
would rather not do that.  We have a backup plan that supports all the netCDF-4 
interfaces on top of HDF5 1.6.5 with more artifacts, but it would make our code 
harder to maintain if we had multiple versions of the format depending on 
multiple versions of HDF5, so I'm resisting taking that route even though it 
mens more delay in releasing netCDF-4.

--Russ

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



Ticket Details
===================
Ticket ID: XJU-559475
Department: Support netCDF
Priority: Normal
Status: Closed