Hello,
Okay, I think I understand now. :) If not, please keep working with me, as I believe I am teachable.
BESR is a disk-based backup solution, meaning that we support writing to disk and optical storage mediums (local hard disks, USB/Firewire, NAS, SAN, network locations, writable CD/DVD drives, etc). If a backup created with BESR made its way onto tape, it was placed there by a means external to BESR (there's nothing wrong with doing that by the way).
If whatever disk or other media type that contains the BESR backups failed, then it's possible those backups would not be recoverable, depending of course on the type of failure, whether the device could be repaired, etc. In your example, if the disk drives within a server (to which backups were stored) failed, then any backups stored to those drives might not be recoverable.
If the media on which backups were stored remained valid, then they could simply be connected to a different, working system and recovered from there. The backups created by BESR (.v2i files) are stand alone backups, meaning they have no true connection or reliance to the system that was responsible for writing them to disk. For example, if a USB drive was connected to an SBS server, and several systems within the network backed up to that USB drive, if the SBS server failed the USB drive could simply be connected to a different system and the backups could be recovered just fine.
Let me know if I've missed the mark again. I hope I didn't just confuse the issue further.
Thanks.