tape software for Unix or Informix backups

tape software for Unix or Informix backups: Anyone using HP Omniback, SCH Reel, or other products to backup Unix files or Informix databases? Does the vendor product provide write protection to the Informix backups from other programs (or even ontape, onarchive, onbar) inadvertently trying to write over them? Do you have some other method to protect tapes from being overwritten before they expire? Onarchive has the parm expiry_date but that just prevents onarchive from overwriting; any other program can overwrite regardless of the parm expiry_date.