> I deleted and recreated the database and tried to copy back those aaaa
> files. Did not work.
OK , that's quite a lot different than what you first wrote.
There are ways to do that kind of thing but you need to have prepared
for it in advance.
Unfortunately I doubt Ingres was shut down cleanly before the USB device
was unplugged so your backup is probably corrupt anyway. Ingres buffers
changes in memory and writes them at intervals, and when it does, it
write everything not just the committed updates. You need to take your
backup using the checkpoint utility (ckpdb) so you can restore just the
committed updates from the archive.
I don't think I can give you much reason for optimism about recovering
this particular database this time. You should destroy it, recreate the
tables, and reload the data from scratch.
In future, as I say, you can recover a damaged database but you need to
do it using the tools provided for the purpose. You will find a lot of
useful information in the 'Backup and Recovery'
(
http://docs.actian.com/ingres/9.2/database-administrator-guide/1846-performing-backup-and-recovery)
chapter of the DBA Guide.
I'm sure there's no need for me to labour the point about not using USB
drives for a database.