Need to eject tape [not stuck] , but robot broken, must address drive direct scsi mt cmd

[gregoire339]

Lads,

I have a fairly straightforward issue, which someone must have handled before. and i assume the solution is common to all MSL2024/4048/8096.   This machine is a smaller 8 tape G2 autoloader SAS. LTO 6,  1 of the cogs in the elevation picker is split, so it is not operating [& I can't get parts for months as i am in a remote part of SE Asia]

So i just want to eject the current tape and manually place tapes in the drive like with a stand alone tape drive.

But there is no over-riding command - all the mt eject commands and tape  tools utilities  -even the emergency eject assume a functioning robot. and interpret the eject command to be handled with the robot picker, when the picker does not respond properly it does not perform the eject.

This must have been handled in the field a number of times by HP engineers and there must be a work around  The tape drive is not stuck and writes / rewinds etc. It just will not perform a stand alone eject command.

I realize i can pull the the drive and manually eject by hand using the cog wheels on the drive, but that would be tediious.  If there is a way to force an eject, so the tape just be slid out by hand. that way i can still use it, with just a minor inconvenience of sliding the tapes in and out..  My other 2 MS4048 units are fibre channel, so will not accept a  SAS LTO 6., other wise i would just do that.

If there is some way to bypass the robot picker interference i would really appreciate.

thanks

-gregoire

[Curtis_Ballard · Accepted solution]

Interesting question, sorry to hear about your problems.

For most tape libraries, if the tape drive were to process an SCSI unload command completely and eject the tape, the tape would stick out into the path of the robotics and cause problems.  Because of the mechanical interferance most tape drives are programmed to only partially eject tapes until the tape library tells them to complete the eject.

A few thoughts that might help, roughly in complexity order.  I regret that I do not at this time have a LTO-6 SAS drive available to experiment with.

* You mention having an MSL4048 - the MSL tape libraries accept mixed drive types and if the MSL4048 firmware is a revision that supports LTO-6 drives (most versions do) then you should be able to move the tape drive into one of your MSL4048 libraries and have that library unload the tape even if the other drives in the MSL are fibre channel drives.

* Most tape drives still have the eject button when installed in a tape library it is just recessed and hard to push without the drive front panel and the button in the front panel.  If you can find some way to push and hold the eject button with the power on the drive will eventually 'force eject' the tape. (something in the 10 second range if I'm remembering right, but might be as long as 30 seconds).  If I'm remembering right that takes a custom "tool" even with the cover removed.  I think the tool was a bend or two in a thin flat piece of metal.

* If the tape drive doesn't know that it is in a tape library then it should eject the tape completely.  If you remove the cover on the drive canister that covers the wiring then you can unplug the library interface cable from the back of the drive then put the drive back in the library and send an eject command and it should eject the tape.  Then you could remove the drive and get the tape out.  Be sure to reconnect the interface cable and put the cover back on.  Do not remove the tape drive from the canister unless you have to as the canister is assembled using an alignment fixture.

Best of luck.  It seems like deep in the diagnostics there was a diagnostic that caused the drive to always eject but that it would eject even if doing so would break the tape so that was only used in the lab.

[gregoire339]

Mr Curtis,

thanks for the  detailed reply.  I had tried the things you mentioned, but realize i can re-vist them. eg my msl 4048  rejected the SAS LTO6, but i now realize if i upgrade firmware it will probably accept the drive. I had also disconnected 2 plugs from the controller board to force the drive into stand alone mode, but then it would not boot, once again if i take another look at it that may be viable just doing 1 plug at a time..  I did examine the drive carefully, i just do not think there is an eject button on this type of drive. There is 1 tiny aperture at the lower left front, but probing it i do not feel any small recessed switch..

However, when i accepted the fact i may have to do manual ejects by physically manipulating the spindles, & cog wheels. I was pleasantly surprised to see you do not have to extract the drive from the cannister and undo screws [ i was getting confused with a different type of drive, i had worked on previously, were this was necessary]. The cog wheel that unprimes the leader pin can just be accessed from the bottom of the cannister assembly, and i just followed the official HP video. But the trick is you have to get to near the end of the video before they cover the half-height LT0 6.  Also there is a bit of skill involved.  After i  practised a few times, i could do it in under a minute.  So i can certainly live with being able to do a tape change in around 2 minutes, after pulling out the cannister from the back.  

So i have really learnt something, i will upgrade the firmware on the MSL4048 to accept the LTO6,, but if for some reason that does not work, pulling the drive & manually extracting the tape now quick and do-able.

OK if you ever come to the Laos PDR, you can count on a free lunch

thanks and God bless

-gregoire