Hello Managers,
our system supports no more than four internal SCSI devices, and all of
them are busy. Now I failed in my first try to install an external box
with a (used) tape device (as far as I can suppose, TZK10 since it worked
with the QIC-525 format DC6525) on our DEC 2000 model 300 with the only
Adaptec AHA-1742A SCSI adapter. According to the documentation on the
adapter, it must be rather simple, it isn't in reality though...
I set an unused SCSI ID for the tape device and, following the documentation
on the adapter, remove all three onboard SCSI terminators, then properly
connected both ends of the SCSI cable, set the terminator on the second port
of the external box, and ... the system hung during the "show dev" command.
Since such a symptom may happen as a result of ID interference, I tested
the real SCSI ID of the new device as follows. I disconnected the internal
SCSI ribbon cable from the onboard port and connected an alternative ribbon
instead, with the only device on it - the tape one. So, I made sure it has
ID=3 whereas the disks occupy IDs=0,1,2,4, and HOST ID=7. It seems to be OK.
Nevertheless, connected as an external device it confuses the adapter.
Some more experiments. I disconnected the external box from the end of the
external cable and set the terminator instead of it (the command "show dev"
hung), then removed it, i.e. remained its end open ("show dev" showed all
the disks exactly as they are).
Is it possible behavior in the case if an external cable is wrong or too
long? But it is no longer than 1m. Both of the connectors of the SCSI cable
are 50-pin, both the cable and the terminator were shipped along with the
Alpha itself. Or may it be the adapter wrong? Of course, there would be
useful one experiment more - to try replacing one of the disks with the
tape drive as an internal device, but it's not very convenient, and I don't
know whether it's worth trying.
In the end, I must have returned to the old situation, but ... what puzzled
me most was that the system booted happily even WITHOUT ANY OF THE THREE
ONBORD TERMINATORS ... (it wasn't until later that I remembered I should
had set them again)...
I would be grateful for any advice,
Irene
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* *
* Irene A. Shilikhina e-mail: irene_at_alpha.iae.nsk.su *
* System administrator, *
* Institute of Automation & Electrometry, *
* Siberian Branch of Russian Academy of Sciences, *
* Novosibirsk, Russia *
*
http://www.iae.nsk.su/~irene *
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* * *
* The road to hell is paved with * Every cloud has a silver lining. *
* good intentions. * *
* * *
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Received on Thu Jun 17 1999 - 08:20:26 NZST