exact dups

I have found a bunch of exact duplicates and am wondering if the existence
of these is already well known.

These items are exact byte-for-byte copies.  My test method was to count
all the files in the data dirs (rock, reggae, etc), then compile a list of
sha1s of those files, then eliminate duplicates from the sha1 list and
count the results.  I found 7848 dups using this method.

Thanks in advance.

- Lucas