Help! Upgrade to 8.4 dropped my databases

Greetings all-

Running postgresql under debian, my standard apt-get upgrade upgraded me
from 8.3 to 8.4. As a result, I no longer have access to the databases
that were created under 8.3. Typically I would use pg_upgradecluster to
fix this problem; however, the upgrade also removed 8.3, and so I have no
access to these databases! Reinstalling 8.3 does not restore the
access, although it does appear that the raw files are still there.

I do have regular tape backups of the databases, but am having trouble
getting them to read. So I would love advice on one (or both) of the
following questions:

1.) Is there a way to "reconnect" the 8.3 server, after reinstalling it,
to the raw files, so that the databases are there? I will then do a
pg_upgradecluster and be happy; or, alternatively,

2.) Can someone help with the restore process from tape? The command my
script uses to write the backups to tape is:
     pg_dump -F t <databasename> | bzip2 -c | dd of=/dev/nst0 obs=512 conv=sync

Thanks for advice on either or both.

==Andy Perrin

----------------------------------------------------------------------
Andrew J Perrin - andrew_perrin (at) unc.edu - http://perrin.socsci.unc.edu
Associate Professor and Associate Chair of Sociology
University of North Carolina - CB#3210, Chapel Hill, NC 27599-3210 USA