I have a Quantum pub called "DLT University Handbook", second edition.  It says
that Quantum "calculates most reliability figures at 100% duty cycle" and
current drives are "rated at 200,000 hour MTBF"  page 5.8.

So, you are right, except, I don't know what "most" means.  I do know that some
Quantum resellers, such as ATL (now part of Quantum) redesigned significant
parts of the drive your use in libraries, particularly the motor controlling
leader load.   ATL always claimed that there MTBF was a true 200,000 hours,
which led me to believe that without these changes, drives running in other
libraries had lower MTBF's.

The real answer would come from Quantum.  They could publish there MTBF based
on field data, not engineering projections.  I have seen other vendors do this,
and there is always a difference between projected MTBF (the engineering goal)
and field MTBF (reality!)

Larry Chisesi
CoComp Technical Services


Paul Zarnowski wrote:

> At 05:00 PM 11/11/98 -0700, Larry Chisesi wrote:
> >     Duty cycles on DLT are based on 10-20%
> >utilization, but ADSM can require much more out of a tape drive.
>
> The literature I have seen on DLT indicated that their numbers were based
> on 100% duty cycles.  If you have evidence to the contrary, I would be very
> interested in seeing it.