PyTables/PyTables — Issue #123: Provide option to set size of UserBlock when creating file
Author: bburan
Created: 2012-01-24 15:49:56+00:00
State: open

HDF5 files provide an optional userblock region at the beginning of the file that the programmer can use to store custom metadata required for their application. This userblock must be created at the same time as the HDF5 file (it cannot be added to existing HDF5 files). The best approach seems to be adding an argument the File() constructor and also, possibly, the openFile() method (but only when the file is created).

I believe HDF5 does not provide a way to write data to the userblock itself (i.e. the programmer must come up with their own way of doing so), so that would be outside the scope of this feature request.

relevant references:
The userblock is described here http://www.hdfgroup.org/HDF5/doc1.6/UG/08_TheFile.html
H5Py also has implemented the ability to set the user block size when creating a file http://code.google.com/p/h5py/source/detail?r=8a3010d07e14