If all books in the library system are cataloged on OBIS, why do we still have the card catalog.
--Trying to study, but reading RAE Board :)
Dear Trying to Study,
I'm surprised no one ever asked this before. It definitely belongs on the QTND Board.
We still have the Dewey card catalog because it has quite a lot of information that's not in OBIS. Although we have cataloged almost all the books and journals in our collection, we still have a small percentage of items to convert to machine-readable form. I'll spare you the details, but they include things like complicated analyzed sets.
The catalog is also a very rich source of information for the history of the library. For example, back in the late 1880s Azariah Root, Oberlin's most famous librarian, cataloged the entire collection. If memory serves me right, there were about 14,000 volumes then. His hand-written cards--they used "half size" cards in those days--are still there. Look through the catalog and you'll see some. (And see Nicholson Baker's passionate defense of card catalogs)