My apologies in advance, since this is admittedly very hardware-specific. 
But, it's happening in conjunction with Networker and I'm wondering if 
maybe there's someone here who's run across this (just for my knowledge of 
what may be happening, since we're currently working around it).

This involves a Sun C2 autochanger, which is a rebranded Quantum 
SuperLoader 3 (one SDLT600 drive, two 8x mags). It originally had just one 
magazine; we added a second mag later, but that's not relevant to the 
issue here. 

If you aren't familiar with this hardware, please accept my apologies for 
this post and ignore me. If you are, maybe you can help educate me.  :-)


Back in November of 2008, I posted this to the list:

 
--------------------------------------------------------------------------
    All of a sudden, I've started getting messages every five minutes from
    what appears to be a (still) fully functional, quite new library. 
 
    Here are the details:
 
    Jukebox `grady', command operation `LOAD', command ID 25461, slot 
`S:000263' is inaccessible. 
    Jukebox `grady', command operation `LOAD', command ID 25461, slot 
`S:000263' is inaccessible.
    Loading volume `Cleaning Tape (5 uses left) CLN838' from slot `8' into 
device `/dev/rmt/0ubn'.
 
    The library shows no other errors from Networker, the OS, nor via it's 

    http management interface (it's a "C2" Sun-branded Quantum SuperLoader 
3). 
    It's been power cycled, the server rebooted, etc., etc. The cleaning 
tape 
    is indeed CLN838, and is in slot 8, but it never gets picked up at 
all, 
    best I can tell. I don't know what "S:000263' is inaccessible" means, 
really.
 
--------------------------------------------------------------------------

That was with 7.4 and I never specifically solved it, but at some point 
thereafter it stopped occurring. It was with only 1 8-slot mag.

Now, I'm at 7.5.1 on another server, with the same autochanger (it has 
been in use for more than a year) and I've just now seen the same error 
when trying to handle tapes in slot 8 (it now has the additional 8-slot 
mag as well):

    Info: Preparing to load volume `001799' from slot 8 into device 
`/dev/rmt/13cbn'.
    Info: Loading volume `001799' from slot `8' into device 
`/dev/rmt/13cbn'.
    Error: Jukebox `scotty', command operation `LOAD', command ID 2662, 
slot `S:000263' is inaccessible.
    Error: Jukebox `scotty', command operation `LOAD', command ID 2662, 
slot `S:000263' is inaccessible.
    39077:nsrjb: error, Jukebox command terminated with errors.

Looks like some kind of hardware issue, no? Maybe with either tapes 
sticking in slot 8 or the robotics not properly picking them up, etc.

Here's what I've observed empirically, in case this maybe rings a bell 
somewhere:

* From Networker, any operation attempting to access the tape in
  the slot, beyond simply scanning the barcode, fails as above.

* From the built-in (web) management interface to the autochanger, 
  I can move a tape from slot 8 to the drive and it says it's 
  successful. But it lies... When I check the unit itself, nothing 
  has moved and there's a message on the LCD saying there's no 
  cleaning tape in slot 8! Uh, yeah... say what?? The cleaning
  cart is now configured for, and resides in, slot 16.

* From the LCD panel on the unit itself, I've successfully moved 
  tapes in and out of the slot several times; no apparent errors.

* I've swapped magazines with another SuperLoader 3; same results.

* I've changed tapes in slot 8; same results as per the slot (i.e.,
  the tapes are OK, the slot fails).

About all I can come up with (definitely theory-wise, not knowing the 
innards of the unit) is that there's some kind of indexing counter in the 
robotics (not per-slot on the magazine) that's intermittently failing on 
slot 8 of any mag once initialized. That is, maybe it reads some indexing 
mark on the mag, eg., slot 1, and then not always successfully keeps track 
of the exact position of slot 8 from that starting point. Otherwise, if 
all slots were indexed on the mag and just slot 8 had a bad mark, there 
would not be the same errors from another mag. But that's just a theory.

For now I've set my allowable slot range to "1-7, 9-15" and removed the 
tape from slot 8. We'll get by just fine without the slot, but I'd be VERY 
interested to know what's causing this in case it decides to choose 
another slot.

Thanks in advance to anyone who can offer any insight.  :-)

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