On 26 Oct, 16:08, H Vlems wrote:
> Last month I bought five KZPCM-DX SCSI adapters. Three of them are in
> use and work wel under both VMS V8.3 and V7.3-2 in Alpha Server 1200's
> and *Digital Server 5305.
> This afternoon the idea of forming a VMS cluster with two 1200's came
> up. I read the manual on configuring OpenVMS clusters for scalability
> (V8.3 kit), especially appendix A. The KZPCM is not listed as a
> supported SCSI interface.
> Questions that I have:
> - the manual doesn't mention the KZPCM at all, perhaps it is supported
> to connect to a common SCSI bus?
> - if not supported, will it work (after all this is a hobbyist
> environment)?
> - if it's not supported and won't work, what's the reason?
> Hans

Spookily, I read a few lines about this kind of thing in the v8.2 New
Features manual this morning. P3-2 says:
"Fibre Channel is supported as a shared-storage cluster interconenct
on OpenVMS I64 systems but SCSI is not. (SCSI as a shared-storage
clsuter interconnect is also not supported for OpenVMS Alpha systems
for the recent SCSI adapters.)"

I'm not sure how recent the KZPCM is off the top of my head.
There were also issues with some differential interfaces and shared
VMS buses, IIRC.

H Vlems wrote:
> - the manual doesn't mention the KZPCM at all, perhaps it is supported
> to connect to a common SCSI bus?

The official source for what's supported is typically the Software
Product Descriptions. Go to http://hp.com/go/spd to find those. Some
SCSI adapter support info will be in the OpenVMS SPD at
http://docs.hp.com/en/12697/OVMS831H1SPD.pdf (I see it notes there is
multi-host support in its description for some SCSI adapters, including
the KZPBA-CB), and more specifics on multi-host SCSI support in a
cluster will be in the OpenVMS Cluster Software SPD at
http://docs.hp.com/en/12700/SPDClusters.pdf. Sometimes support info will
be in the Release Notes or New Features or Installation Guide for a
given version of OpenVMS. Finally, the OpenVMS Roadmap at
http://hp.com/go/openvms/roadmap can provide clues about future (and
recent) additions to capabilities.

> > - if not supported, will it work (after all this is a hobbyist
> environment)?
> - if it's not supported and won't work, what's the reason?

The host SCSI adapters on different VMS nodes actually briefly talk to
one another and exchange just enough info that VMS can avoid conflicts
in port allocation class assignments between different systems connected
to the same SCSI bus. There was hope at one time that host-to-host
communcations over SCSI could be broadened to include SCS traffic in
general, but that didn't work out. The NCR chip was the first supported
in multi-host configurations and seems to be used in at least many of
the SCSI adapters which support multi-host operation on Alpha. If a
specific adapter doesn't work, my guess would be that it's probably due
to differences in its SCSI interface chip design.

etmsreec@yahoo.co.uk wrote:
> Spookily, I read a few lines about this kind of thing in the v8.2 New
> Features manual this morning. P3-2 says:
> "Fibre Channel is supported as a shared-storage cluster interconenct
> on OpenVMS I64 systems but SCSI is not. (SCSI as a shared-storage
> clsuter interconnect is also not supported for OpenVMS Alpha systems
> for the recent SCSI adapters.)"

The OpenVMS Cluster Software SPD at
http://docs.hp.com/en/12700/SPDClusters.pdf says:
"Beginning with OpenVMS V8.2-1 on Integrity servers,
a 2-node shared SCSI environment is provided via the
MSA30MI shelf between Integrity Server nodes ONLY."

and

"Dual-Host SCSI Storage Support (for Integrity Servers)

OpenVMS Integrity server systems that are members of
the rx1600 and rx2600 families can form a 2-node Open-
VMS for Integrity servers Cluster system with shared
SCSI storage. The configuration has many restrictions
as documented in HP OpenVMS Version 8.2–1 for Integrity
Servers New Features and Release Notes."

The OpenVMS Roadmap at http://hp.com/go/openvms/roadmap says shared SAS
(Serial-Attached SCSI) cluster support for the MSA60/MSA70 is included
in 8.3-1H1.

On 28 okt, 19:32, Keith Parris wrote:
> H Vlems wrote:
> > - the manual doesn't mention the KZPCM at all, perhaps it is supported
> > to connect to a common SCSI bus?
>
> The official source for what's supported is typically the Software
> Product Descriptions. Go tohttp://hp.com/go/spdto find those. Some
> SCSI adapter support info will be in the OpenVMS SPD athttp://docs.hp.com/en/12697/OVMS831H1SPD.pdf(I see it notes there is
> multi-host support in its description for some SCSI adapters, including
> the KZPBA-CB), and more specifics on multi-host SCSI support in a
> cluster will be in the OpenVMS Cluster Software SPD athttp://docs.hp.com/en/12700/SPDClusters.pdf. Sometimes support info will
> be in the Release Notes or New Features or Installation Guide for a
> given version of OpenVMS. Finally, the OpenVMS Roadmap athttp://hp.com/go/openvms/roadmapcan provide clues about future (and
> recent) additions to capabilities.
>
> *> > - if not supported, will it work (after all this is a hobbyist
> *> environment)?
> *> - if it's not supported and won't work, what's the reason?
>
> The host SCSI adapters on different VMS nodes actually briefly talk to
> one another and exchange just enough info that VMS can avoid conflicts
> in port allocation class assignments between different systems connected
> to the same SCSI bus. There was hope at one time that host-to-host
> communcations over SCSI could be broadened to include SCS traffic in
> general, but that didn't work out. The NCR chip was the first supported
> in multi-host configurations and seems to be used in at least many of
> the SCSI adapters which support multi-host operation on Alpha. If a
> specific adapter doesn't work, my guess would be that it's probably due
> to differences in its SCSI interface chip design.

Thank you for the detailed answer Keith.
The KZPCM uses an NCR chip, so it might just work. I'll connect two
systems and
see whether they recognize each others disks. Without errors that is.
Hans