Revision History Saves the Day
Amidsize software company had a script that automated the process of account creation.
One day, the disk that contained the account database filled up while the program was
rewriting the database. Because it did almost no error checking, the script failed to
notice. It proceeded to push out the new account database to all the authentication
servers, even though it was missing most of the accounts. The SAs quickly realized what
had happened and were able to immediately clear some space and go back to the old
account database as it existed immediately before the script was run. If they had not had a
revision history, they would have had to restore the file from backup tape, which would
have taken much longer and meant that any password changes customers had made
since the backup would have been lost. The automated program had identified itself in
the optional comment field, and thus it was easy to track down the entity responsible for
the truncation. The script was subsequently changed to do a lot more error checking