On Apr 20, 2006, at 12:29 PM, Gill, Geoffrey L. wrote:

Why it is LTO2 capacity reads differently than 3590's. My 3590's
report 40GB
when filling and "at least" 40GB when full. K tapes read 20/40 and
LTO2's
200/400. So why wouldn't it show at least 400?

Is this a TSM, LTO or some other issue causing this?

Estimated Capacity is an arbitrary, settable number, principally to
guide humans in an expectation of how much a given media may hold.

Is a tape reporting 215GB when full really holding more than that?

That is the amount of data which TSM wrote through the drive.

It also makes no sense if estimated capacity is 400GB, and the
drive is
capable of supporting that, it only reports 200.

Sure it does... The native capacity of LTO2 is 200 GB (plus or minus
a tad, depending upon the actual length of the individual tape).
Think of a tape as containing 200 billion cells, and no more: the
tape is incapable of holding more units than that. If the incoming
data is compressible, the drive can store a representation of that
original data and use fewer "cells" doing it, and *effectively* store
more data on the tape.

  Richard Sims