[R] A file with extension .sdb in a codebook section of a large database from a survey?

[Douglas Bates]

The TIMSS2007 database http://timss.bc.edu/TIMSS2007/idb_ug.html seems
to provide "both kinds" of universal data formats - either SPSS saved
data sets or SAS saved data sets.  (Yes, I am being sarcastic.)
These, of course, are accompanied by massive codebooks explaining the
nature of each of the fields in the data sets.  The T07_Codebooks.zip
file available at that site contains .pdf files and .sdb files, which
seem to contain the information from the codebooks in some kind of
binary format.  Does anyone know where that format is defined.  I
imagine I could reverse-engineer it but would prefer not to do so.

I would like to use part of this dataset as an example of a very large
hierarchically structured data set for analysis in lme4.