I've got a lot to say today, I guess.

I am the proud parent of a bouncing baby 3584-S24 frame.  That's one
of the new "high-density" frames, with tape slots that are four (or in
the LTO case, 5) tapes deep.  This means that I've got 1000 slots in
the floorspace which used to hold 400.  For you LTO types, it's
440->1320.

The device is quite neat, and I think that any of you whose libraries
are not usually waiting on the gripper as a bottleneck in your systems
might want to consider at least one of them.


The basic idea is that, on the "back" wall (not the door) in the
volume taken up by drives and stuff in the D frames, there are
springloaded slots which can hold several tapes.  The gripper plays
Towers Of Hanoi with them to get the tape you want.

There are several rows of tape slots at the top (and bottom??) which
are marked with 'construction' / 'caution' yellow and black stripes,
which I understand implies you're not to manually stick tapes there.

When you insert a bunch of tapes in the frame, you get this funky
double-tap behavior out of the gripper.  It moves to the top (for
example) of a row, with the two dont-touch-me cells above it,


+ Scan top two tapes (i.e. first cell and second cell down)
+ Grab top two tapes (revealing the second on each shelf)
+ Insert top two tapes into construction zone


It does this four times, (or maybe fewer if you've got less than four
tapes in each slot).  At this point, it's generated two -new- empty
cells in the top and second cell.  So, it moves down two, and does the
same thing again.  At the end of the inventory process, every tape has
been shuffled and is two slots up from where it was.



Of course, it's totally scrambled the physical element addresses; for
this reason you have to buy the "ALMS" feature code, which puts an
abstraction layer between the virtual element address and the
physical.

As a bonus, this means that the library can gradually churn your
volumes so that the more frequently used ones stay on the one-deep
slots, and the rarely used one shuffle to the back.  It's my guess
that for sites with a normal distribution of tape mounts, this will
result in not-much average increase in tape delay.



If you get ALMS up and running before you get started with the
physical install, it'll smooth the path for your SE.  If you get your
microcode up to the very latest too, it'll make his life even easier.

- Allen S. Rout