Karen said:

>So the actual meaning of the>subfields is that the 050 $a$b is the LC
>"call number" (including the class number

Yes.  The 050$a$b is the class-as-collection call number, with the
series or set class number in $a, and the series or set Cutter plus
number and sometimes year in $b.  The second $a is the monograph class
number if the item were not be classed as part of a series or set.

When we use the second $a, we created a second 050 with $a$b, and
remove the second $a form the first 050.

It is possible to automate that process.  One can move the second $a
to another 050 and automatically assign a Cutter based on the main
entry (be it 1CC or 245) plus year.  One can *not* use the first $b
with the second $a beasue it is based on a diffent entry, series entry
vs. item entry.

I've seen no mention of the conversion of other knowledge numbers
(055, 060, 070, 080, 082, 086, 090, 092) each of which presents its
own difficulties.  

For example, how to distinguish between standard LCC in LAC's 055, as
opposed to numbers unique to Canada (F5000, FC, KF for common law,
PS8000, and sometimes Moys K). There are also 055s with "*" rather
than subject or geographic Cutters, because that Cutter might differ
in Anglpphone and Francophone libraries. Before the up-to-dateness of
Classweb, I tried to persuade LAC to use different symbols for subject
and geographic Cutter, so we would know which to apply; the class
number with the "*" was sometimes not yet in the printed schedules.

Actual working cataloguers would know all this, documented or not.


   __       __   J. McRee (Mac) Elrod ([log in to unmask])
  {__  |   /     Special Libraries Cataloguing   HTTP://www.slc.bc.ca/
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