> I gave some more thought to this problem, and my theory of using
> NBackup would not work because of the embedded engine, unless your
> process disconnected totally from the database, unless NBackup is
> available through some API that I am not yet familiar with.

For full file-level backup, all you need to do is execute
ALTER DATABASE BEGIN BACKUP
then make copy of db file, then
ALTER DATABASE END BACKUP

> Creating a thread and connecting to the services API to do a backup
> from that thread is the best solution as it guarantees the backup will
> not be corrupt and does not interfere at all with your application.

Both methods (NBackup-like and ServicesAPI-GBAK) are safe,
so you can choose which method is better for you
(i.e. either fast physical copy, or slower logical backup)

Ivan
http://www.volny.cz/iprenosil/interbase/