Of many tape formats I have used over the years (from 2400" 800 bpi NRZI 9 track reel-to-reel on) DAT and 8mm drives did prove to be the most temperamental (e.g. the drive would claim it needed cleaning two tapes after being cleaned, or would refuse to surrender the medium it has swallowed etc), but once the read-after-write drive wrote the tape and claimed it OK, it generally really was OK. Having said that, they cannot compare to old 9 track drives or, even less, disks.

Tape backup is generally really not intended to be read, meaning it is there just for disaster recovery. That's why I don't consider speed of access (or lack of it) very important: if your hard drive dies, you just recover all of its content from the tape backup.

However, given tape's far from total reliability, one has to advise backup strategy where there will almost always ba a way to bypass a bad tape (e.g. keeping three most recent total, baseline backups and all incremental backups between them, keeping a copy of recent incremental backups on a separate medium, doing fresh baseline backup whenever major or important change happens). OTOH, a decade of administering (among other things) other people's massive databases and their backup has probably made me too paranoid .

Considering using disk as backup: it is just too hard for me not to swamp it with garbage. My files really do expand to fill all the available space (on my home computers, anyway) .

Dragi "Bonzi" Raos
Zagreb, Croatia
Q#5196, MkII#80000376, 18GB green