>We are using STK 9840 drives.  The 9840 drives seem much more reliable than
>the 3590.  We have had some problems with the reliability of the 9840 tapes.
>When one fails, we have lost between 20 and 120 gigabytes of data.  One way
>to work around the 9840 reliability is to dual copy most backups.

As a medium open to the elements and subjected to a lot of mechanical wear,
creation of Copy Storage Pool backups is de rigueur for any type of tape
if the data is of importance.
But how is it with 9840s that you lose so much data when a tape goes bad?
Are these single, huge files?  Usually, when a "bad spot" occurs on a tape,
only the file in which it occurs is lost: those around it tend to remain
usable.  (This varies by recording technology (serpentine, whatever).)

>One disadvantage of the 9840 drives is that the service techs are not
>allowed to perform many services on the drives.  If a drive malfunctions, it
>must be pulled and replaced.  I do not know if this applies to the 3590
>drives.  We have an excellent relationship with our STK service reps, and
>they seem concerned about our business, not just meeting the terms of their
>service contract.  IBM is not concerned about our business, and service
>calls to IBM are often frustrating.

Maybe an advantage.  We've had IBM CE's spend a whole shift or more on site
working on a 3590 drive.  At those times I would have preferred that they
brought in a remanufactured replacement unit to replace the downed unit.

   Richard Sims, BU