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Hi Charlie, (I meant to send this support response rather than a private email.) Ed is away for a couple of weeks, and he's the one best able to answer your question. It might be helpful if you can provide us with a simple example of a program that creates a chunked netCDF-4 file fails with a code -101 HDF error. If that's not convenient, then it would be helpful to get the actual HDF error, which you can do by configuring like this: ./configure --enable-logging --enable-netcdf-4 --disable-f77 --disable-cxx --with-hdf5=... make check Then if your test fails, insert the following line: nc_set_log_level(5); in your test case, before the point where the failure occurs. This will produce some log output telling us what is going on. Thanks! --Russ > I have implemented access to the netCDF4 chunking features in NCO. > The "all or nothing" approach---chunking all the variables or none--- > usually works as expected. However, "moderately chunked" approaches--- > where, say, only the 3D variables are chunked, or only the variables > containing a certain dimension---often fail in the HDF library > (error code -101 = "HDF error"). Also, unchunking a completely chunked > dataset fails. > > As I understand it, the chunking of one variable is completely > independent of the chunking of the rest of the variables, i.e., > netCDF4 imposes no special restrictions on chunking (or not) > coordinate variables, record variables, etc. > To me, this indenpendence means that if I chunk one variable that > contains a certain dimension, "longitude" say, then I do not have > to chunk all the other variables that contain "longitude". > My understanding is that I can chunk (or not) any variables I like > as long as each dimension's chunk size is <= the dimension size. > Are there any chunking constraints/limitations present in the HDF > layer that might cause the symptoms I encounter? > > As important, I do (sometimes) call nc_def_var_chunking() multiple > times for the same variable before an nc_enddef(). I assume this is OK > and that each variable will be written with the parameters set for it > in the last nc_def_var_chunking() call before nc_enddef(). > > Thanks, > Charlie > -- > Charlie Zender, Department of Earth System Science > University of California, Irvine (949) 824-2987 :) > > _______________________________________________ > netcdf-hdf mailing list > address@hidden > For list information or to unsubscribe, visit: > http://www.unidata.ucar.edu/mailing_lists/ > > Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: VKC-963616 Department: Support netCDF Priority: Normal Status: Closed