The seperation of dc/ and trk/ packages as I see is, dc/ is for
drift chamber calibration and trk/ for track reconstruction. We
have to work on it to have a clear and clean seperation. I don't
see any real personal preference to common blocks over bos banks.
They are more for historical reasons.
We can do such that no tcl variables and routines in dc/ are used
in trk/. If we replace common blocks with bos banks, there will be
no common common blocks either.
Regards,
liming