tape changer, but not tape drive

[Dan Langille]

Adam McDougall wrote:
> Dan Langille wrote:
>> Adam McDougall wrote:
>>> On Tue, Oct 27, 2009 at 09:39:07PM -0400, Dan Langille wrote:
>>>
>>>   I first encountered this problem in April, now I'm back to it:
>>>        
>>> http://lists.freebsd.org/pipermail/freebsd-scsi/2008-April/003452.html
>>>     In short, the system has tape library.  The library has worked in 
>>> the   past (http://www.freebsddiary.org/digital-tl891.php) but now it 
>>> does   not.  I can see either the tape library or the tape drive.  
>>> Which I see   depends upon the cable configuration.
>>>        http://www.freebsddiary.org/images/tape-libraries-cables.jpg
>>>     As shown above, that's how I would expect things to work 
>>> normally.   However, in that configuration, I do not see the tape 
>>> drive.  The cable   going down, goes to the computer.  If I reconnect 
>>> that cable to the plug   to the left of the terminator, the system 
>>> can see the DLT drive, but not   the tape library.
>>>     Under 6.3-STABLE FreeBSD, I can see either one device or the other.
>>>     ch0 at ahc0 bus 0 target 0 lun 0
>>>   ch0:  Removable Changer SCSI-2 device
>>>   ch0: 20.000MB/s transfers (10.000MHz, offset 8, 16bit)
>>>   ch0: 10 slots, 1 drive, 1 picker, 0 portals
>>>     or
>>>     sa0 at ahc0 bus 0 target 1 lun 0
>>>   sa0:  Removable Sequential Access SCSI-2 device
>>>   sa0: 20.000MB/s transfers (10.000MHz, offset 8, 16bit)
>>>   acd0: FAILURE - INQUIRY ILLEGAL REQUEST asc=0x24 ascq=0x00 sks=0x40 
>>> 0x00   0x01
>>>     Any ideas?
>>>     Full dmesg output here:  http://www.langille.org/tmp/dmesg.boot
>>>     TIA.
>>>   Is it possible the middle cable is broken in some way?  Perhaps you
>>> could swap it with another cable to try to find out, such as with
>>> the cable going from the library to the 2944 card.  Might be 
>>> intermittant
>>> and start working if bent or moved. 
>>
>> I did try that.  I used the cable from my stand-alone DLT drive, which 
>> has been used before (and after) and is known to be good.
>>
>>> Also can you see the connectors
>>> inside the library (on the back side of the external plate) to check
>>> if they are well seated or damaged?
>>
>> I'll pull the unit apart and have a look.  I have been in there 
>> before.   Since it last worked, the unit has gone through two moves.
>>
>> > You could also try swapping the
>>> first and second connection or the third and fourth, or both, if it is
>>> hooked up like I think it is, those should have an equal chance of 
>>> working
>>> and might reveal a bad port or partially bad port.  
>>
>> I did try moving the looped cable to plugs 1&2 and connecting my 
>> computer to plug 3.
> The two plugs for each device (library, tape1, tape2) are probably tied 
> directly together in a Y
> shape to the internal device so you can use them as an In/Out, so 
> putting the looped cable on
> plugs 1 and 2 probably does nothing and isolates that device from the 
> rest.  As long as the looped
> cable is not between 1&2 or 3&4, you can probably use any other order 
> although the manufacturer
> may have recommendations.  I see nothing wrong with the way you appear 
> to have cabled it but
> variations may reveal something.

I looked inside.  Nothing obviously disconnected etc.

I tried connecting the computer into plug 1, leaving 2 and 3 empty. 
Regardless of whether or not the terminator is in plug 4, FreeBSD does 
not see the tape drive.

FWIW, I went into the SCSI utility for the SCSI card during boot.

ahc0: <Adaptec 2944 Ultra SCSI adapter> port 0x9400-0x94ff mem 
0xfb400000-0xfb400fff irq 16 at device 9.0 on pci0
ahc0: [GIANT-LOCKED]

The card itself sees only the library, not the drive.  Thus, I conclude 
this is something outside FreeBSD (so far).

>>
>>> Also try leaving off
>>> the terminator or one/both ends of the middle cable just to see if the
>>> system can tell the difference especially while booting, just to confirm
>>> if it makes any negative difference at all.  
>>
>> OK, I will try that.
>>
>> Thank you.

No difference.