From:	CRDGW2::CRDGW2::MRGATE::"SMTP::CRVAX.SRI.COM::RELAY-INFO-VAX" 18-AUG-1989 03:28
To:	MRGATE::"ARISIA::EVERHART"
Subj:	Fix so generic SCSI disks are visible cluster-wide

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Date: Thu, 17 Aug 89 18:50 PDT
From: Ned Freed <NED%HMCVAX.BITNET@CUNYVM.CUNY.EDU>
Subject: Fix so generic SCSI disks are visible cluster-wide
To: info-vax@kl.sri.com
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Several people have asked for this, so I thought I'd post it to info-vax. I'd
like to toot my horn a little by saying that we figured this sucker out before
the ufiche for the driver were available. However, we did have a hint from a
friendly person at DEC as to where the trouble might be. The unofficial word
was "fixed in a future release".

The basic problem is that third-party SCSI disks work fine on VAX 3100 systems
locally, but they don't serve to a cluster. This problem is due to a sanity
check in the MSCP server code on the device's media ID. Unfortunately, generic
SCSI disks haver a zero media ID that fails this test.

The following patch to DKDRIVER sets the media id for generic SCSI disks to be
the same as the media id for RZ55 disks ("DK" in five bit). The patched
location is in a entry in a table that maps SCSI device names (read directly
from the device) into various pieces of information VMS needs. While the
default zero media id does not interfere with local operation of the disk, a
nonzero media id is required by the MSCP serving subsystem (the disk can be set
served but other systems will not recognize it).

This patch is only valid for VMS 5.1B and 5.1-1. DEC is aware of this problem
and it should be fixed in a future release of VMS, hopefully 5.2

Please send any question or comments directly to me since I am not a regular
info-vax reader.

                                Ned Freed
                                ned@ymir.bitnet


  PATCH  Version 4-00    15-Sep-1984

IMAGE FILE BEING PATCHED:       "VOLSUNG:[CONFIGURE]DKDRIVER.EXE;1"
JOURNAL FILE:                   "VOLSUNG:[CONFIGURE]DKDRIVER.JNL;1"
DATE/TIME OF PATCH:              8-APR-1989 03:40:24.91

%PATCH-I-NOLCL, image does not contain local symbols
PATCH>repl/long 30d
OLD>  00000000
OLD>  exit
NEW>  22e5a037
NEW>  exit
old:    0000030D:  00000000
new:    0000030D:  22E5A037
PATCH>update
%PATCH-I-WRTFIL, updating image file VOLSUNG:[CONFIGURE]DKDRIVER.EXE;2
PATCH>exit

