[Info-vax] SCSI question (KZPEA-CX adaptor)

[Christoph Gartmann]

In article <001c5c77$0$19603$c3e8da3 at news.astraweb.com>, JF Mezei <jfmezei.spamnot at vaxination.ca> writes:
>I finally installed a KZPEA-CX adaptor on a DS10L.
>
>I had some adaptor that fitted onto the external plug of the KZPEA-CX
>and provided a standard 50 pin ribbon cable interface.
>
>Plugged in a CD drive (old Sony drive very similar to the RRD42). The
>SRM console would see the drive, get its identity, generate a DKA400:
>device. But couldn't boot from it.
>
>>>>>show dev
>> dka400.4.0.17.0            DKA400        SONY CD-ROM CDU-8003A  1.8f
[...]
>So it detects that this old SCSI drive is a narrow ("no" to "Negotiate
>Wide") and that it doesn't suport tagged queuing.
>
>However, trying to do a "Verify media" results in it telling me it isn't
>a disk device.
>
>However, booting into VMS:
>
>
>> $ show dev $10$dka400:/full
>> 
>> Disk $10$DKA400: (BIKE), device type SONY CD-ROM CDU-8003A, is online, file-
>>     oriented device, shareable, served to cluster via MSCP Server, error logging
>>     is enabled.
>> 
>>     Error count                    0    Operations completed                  0
>>     Owner process                 ""    Owner UIC                      [SYSTEM]
>>     Owner process ID        00000000    Dev Prot            S:RWPL,O:RWPL,G:R,W
>>     Reference count                0    Default buffer size                 512
>>     Allocation class              10
>
>But:
>
>$ mount/nowrite/override=id    $10$dka400: test
>%MOUNT-F-MEDOFL, medium is offline
>
>
>I Have tried this with different setups, including plugging the 50 pin
>ribbon cable directly into the KZPEA card's internal 50 pin connector.
>
>
>QUESTIONS:
>
>If the controller is able to find out the identity of this device,
>notice it isn't wide etc:
>
>	-does this mean that the connection (cable, adaptor etc) is fully
>functional?

No, this means that there is some data exchange between the CD-ROM and the
host and hence, there must be some sort of connection.

>or are there primitive exchanges (such as getting
>information from device) which can be done with a deffective connection
>but when you try to do real access to the device , it fails ?

This is pretty common.

>	-the card is set to have auto termination. Would an unterminated  CD
>ROM drive at the other end of the cable cause this behaviour ? I'd have
>to search for the specs of this drive to see if it is terminated or not.

Termination is important. I wouldn't rely on auto-termination. The last device
on the bus has to be terminated. Thus, enable termination on the drive and
disable auto-termination on the card.

Regards,
   Christoph Gartmann

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