In the days when I did programming, all our magnetic media were backed up on to punched paper tape (well mylar actually). At least if the tape got damaged you could stick some new tape over it and punch out the holes again.

Don't fancy that on the megabyte files of today though!

DAT and DLT are used in computing for backup.

Memory sticks from the better manufacturers are guaranteed a 10 year life, which is probably better than CDs, many commercial versions of which are falling to bits already.

John