> From owner-netcdf-hdf@xxxxxxxxxxxxxxxx Fri May 15 15:48:37 1992 > Date: Fri, 15 May 1992 16:42:13 EDT > From: "Lloyd A. Treinish" <lloydt@xxxxxxxxxxxxxx> > To: hdf-netcdf@xxxxxxxxxxxxx > Cc: goucher@xxxxxxxxxxxxxxxxxxxx > Subject: CDF, netCDF and HDF > > A second issue is data structure residency and how it is supported. For > scaling to any reasonably interesting data set by size, structure and breadth > (i.e., number of parameters/variables/fields), data structures must be disk- > resident and have a built-in caching mechanism appropriate for those > structures. Both CDF and netCDF attempt to do this. In addition, > transaction- > like operations on data must be supported. In other words, the ability to > query, update/modify, delete data in-place is required. If a substantial > investment in building a large data set is made, it is too expensive to make > updates via copying. If I am current in my knowledge of the netCDF and CDF > implementations then this is supported in CDF and not in netCDF. In the HDF > case none of these ideas apply because the data structures are memory > resident. Well, in netCDF, you can "query, update/modify, delete data in-place" as required. You can change the value of attributes. What you can't do, without copying, is change the "shape" of the netCDF once it has been defined.