x@x.x wrote:
> In article <4372c5e7@212.67.96.135>, Dave <nospam@nowhere.com> wrote:
>
>>Triffid wrote:
>>
>>
>>>>Thanks for that.
>>>>
>>>>I checked and found the disk was already jumped SE. I removed the
>>>>jumper (what else to try?) but no luck. I tried a few other jumpers,
>>>>but no improvement.
>>>>
>>>>What was odd though is that
>>>>
>>>>a) The disk is seen if it is the *only* disk in the machine.
>>>>
>>>>b) The disk is seen if it the lower slot (SCSI ID=3), but not if its
>>>>in the upper one (ID=1). And no, there are not any jumpers installed
>>>>on any of the SCSI ID select pins.
>>>>
>>>>Anyway, it is at least semi-resolved. I've put an operating system on
>>>>it and it boots OK now. Just needs to be in the lower slot, otherwi4>>> it can't be seen on the bus.
>>>
>>>
>>>That's rather odd. There is no physical or logical difference between
>>>the upper and lower drive bays aside from SCSI ID AFAIK.
>>
>>Yes, I thought it odd too.
>>
>>
>>>I suspect your upper bay is b0rked somehow, and won't work with any disk
>>>as a result.
>>
>>That is not so.
>>
>>Here you can see the Compaq disk that presents me trouble in the lower
>>slot (ID=3) and a Seagate one in the top one (ID=1)
>>
>>
>>ok probe-scsi
>>Target 1
>> Unit 0 Disk SEAGATE ST39103LC 0001LS482885
>> Copyright (c) 1999 Seagate
>> All rights reserved
>>Target 3
>> Unit 0 Disk COMPAQ HB00931931 03F168224A01GAGSPCQ3F1
>> 09RI9904200012259H7007
>> E32284 Q59H6952B09E31916 1999
>>ok
>>
>>
>>After I swap the disks around, using the same machine, the Compaq one
>>can no longer be seen.
>>
>>ok probe-scsi
>>Target 3
>> Unit 0 Disk SEAGATE ST39103LC 0001LS482885
>> Copyright (c) 1999 Seagate
>> All rights reserved
>>ok
>>
>>
>>That behaviour is repeatable.
>
>
> Is one of these hardwired to SCSI Target 3, and the other one is picking
> it up from the slot/position. Like IDE in cable select mode.
>
> So one would be switching 1 and 3, and the other stuck on 3 and 3,
> and colliding in one of the configurations.
>
> Is there a way to force it to target 2 ??

No, the SCA backplane in SS20s is hardwired to IDs 1 and 3.

Only way to change it is with a soldering iron :-)

Triffid

>>But when I move the disks to another SS20, both can be seen in any
>>position, but I'm pretty sure they had the same problem in yet another
>>SS20.
>>
>>
>>
>>>I have a couple of spare SS20 backplane & cable assemblies here
>>>(Toronto, Canada), perhaps you could try one if the logistics aren't too
>>>complicated.
>>
>>Thanks, but I am in the UK, so a long way from you, but in any case I
>>have five SS20's here.
>>
>>
>>>Triffid
>>
>>
>>It all seems very odd. But I have had problems with other Compaq disks
>>in SS20's before, so this is not a total surprise to m<
>>