SUMMARY: Hypothetical Question: LTO Drives into L1000 robot ?

From: Tim Chipman <>
Date: Wed Feb 06 2002 - 11:23:50 EST
Thanks to everyone who replied (Troy Abernathy, "thetrick", Anil
Sreedharan, Charles Rawls, Edmond van As, Jeff Kennedy, Steve
Mickeler).  There was a wide range of thoughts submitted on the matter.

Bottom line: I'm doing nothing for now, trying to learn a bit more. (I'm
not holding my breath though). Much feedback kindly drew my attention to
the fact that DLT, LTO are not absolutely identical in physical
dimensions. A number of replies indicated that it was quite possibly a
"doable" thing, depending on a number of unknowns (primarily, the
ability to tell the robot the new physical spec for the tapes it is
grabbing ; possibly requiring an upgrade of the "gripper unit" itself.).

Greater detail is given below for those who are into reading about this
sort of thing.

--Tim Chipman

-> DLT and LTO are not the same width, height or capacity

[indeed, quite my goal - if they were the same capacity, then there is
little point in this sort of upgrade :-) ]  -- but the real issue here,
the dimensions, compare thus:

LTO: 4.02" x 4.15" x 0.85"
DLT: 4.16" x 4.15" x 1.00"

-> apparently it should be "doable" but not trivial ; may require
upgrade of the "gripper" unit that physically grabs the tapes ; likely
requires some means of telling the robot firmware the new dimensions of
the tapes. I wasn't intending to keep DLT support in the upgrade (ie,
mixed media library) but apparently this reply suggests that it might be

"Not insane nor impossible, but not recommended.  I have an ATL P6000
and I know for a fact it can be done, mixed media capability.However,one
reason it's not recommended is that you need to slice and dice the
library.  Media slots must be logically partitioned to belong to 2
different media sets.  Doable but not easy to spec out as you may not
know how many LTO media you need to handle the data you plan to send to
it.  Another is mixing the media in wrong slots.  If you or someone else
accidentally put LTO media in a DLT slot very bad things will happen, to
the point where you may have to call onsite support to fix your
robot..... And finally is whether or not you need to upgrade your robot
to handle both types of media.  Even with SDLT I need to have a
'universal gripper' to handle both."

-> In keeping with the "affirmative" voices: two replies suggested
(basically) that the robot library itself knows nothing about tapes
other than their physical property (size, location in the bank). So long
as different dimensions (height,width) for tapes could be accounted for
(?somehow?) then the robot really should not care.

"The changer / library has no consideration of tape size.  When it hits
the end of tape, or is issued a dismount, it pulls the tape out
and replaces it with the next tape.

As long as the tape drive itself is recognized by Solaris, you should
have no issues.   I've done this type of thing in the 8mm world,
the big PITA is when the mounts don't quite line up right ..."

and ...

"They may be the same in x-y directions, but they are definately only
2/3 as thick.  The picker would have to be able to understand the
difference. It is possible to reprogram some libraries (older 
E-mass libraries, for instance), but as to yours specifically, 
I don't know."

-> One person suggested to buy a reburb L3500 (for example) with DLT as
a means of getting capacity scaling on backups, rather than investing
more in the L1000 robot. (ie, upgrade 4 SDLT drives into an L1000 might
cost upwards of $40k usd, vs. a refurb L3500 with 7 x DLT7000 drives for
~$20k USD).

I'm not at all certain we prefer to invest in old gear or not. Currently
the price on L20-type units (or the HP gear they are derived from) - a
dual-LTO-drive, 20-tape robot - has quite an attractive look to it. The
capacity and throughput are very decent.


 This is likely a flight of folly, but possibly worth asking. No better
 resoure than this list I can think of for such a query :-)
 I'm curious if it is even concievable to put LTO drives into an L1000
 robot (which currently has DLT drives in it). [AFAIK the LTO and DLT
 tapes are physically ~identical hence the robot itself shouldn't be too
 bothered by this aspect of the change?.. however, it probably would 
 require the tape drive physical specs to be identical as well though,
 which might be a bit more tricky I suspect..?]
 I'm quite certain that quantum support putting *superDLT* into the
 L1000 (although sun doesn't support this yet) .. but I'm curious
 about LTO instad of sDLT for this kind of crazy upgrade.
 Given the increased throughput and capacity of LTO drives over DLT, it
 would be a rather nice upgrade path if it were to be an option.
 If anyone has any ideas on the feasability of this, I'd certainly
 appreciate hearing your thoughts. [ie, "insane" ; "I've done it" ;
 Tim Chipman
sunmanagers mailing list
Received on Wed Feb 6 10:25:13 2002

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