Weird, however, that I can mount an ODS-5 drive on the VAX and indeed do directory listings and the like. Wouldn't believe it if I hadn't seen it. Is it some feature of 7.3.1 that I didn't know about? Or maybe specific to mounting drives in a cluster? Strange indeed. HELP INITIALIZE /STRUCTURE on Alpha VMS 7.3-1 says that VAX deos not support Structure Level 5 disks, and specifying 5 on VAX results in an error. I don't have a 7.3 VAX system to hand to check what that says. The help for MOUNT is silent on the issue. I wonder what happens if you try to access filenames with ODS-5 specific features from the VAX side? Regarding AUTOGEN - I tried what you suggested and there were no differences between the before and after files. I can post them if you like, but I'm not sure they are going to be much use. Bother! I neglected to include "USE CURRENT" before the SHOW commands! As result, both BEFORE.TXT and AFTER.TXT ended up listing the "active" parameter set, ie what is in memory. AUTOGEN, on the other hand updates the "current" parameter set which is the parameter set on the disk. Assuming you have now rebooted after the AUTOGEN, if you now repeat: $ DEFINE /USER SYS$OUTPUT AFTER.TXT $ MCR SYSGEN SHOW /ALL SHOW /SPECIAL ^Z You should get an updated AFTER.TXT suitable for comparison with BEFORE.TXT which was generated before the AUTOGEN. This should then reveal the changes AUTOGEN made. (It would be unusual for AUTOGEN to result in no changes at all.) Note that having manually changed the parameters with SYSGEN the system should be in line with the MODPARAMS file which is what I saw. But haven't you done an AUTOGEN already as part of the commands I suggested for comparing the system parameters before and after it? If you have, AUTOGEN will have set the system parameters taking account of what it found in MODPARAMS.DAT. I'm going to back up the ALPHASYSTEM disk when it's offline and then I'll try an AUTOGEN and see what happens this time. Maybe it was something else which is now working. With a backup it will be trivial to revert. A backup is always good to have. The system disk move from ODS-5 to OSD-2 was uneventful. I created an extra shadow member $4$DKC500: in shadowset DSA0: which was running on $4$DKB0: and $4$DKB100:, then I dismounted the new member $4$DKC500: and $4$DKB100:. I then followed the instructions here: http://h71000.www7.hp.com/doc/73final/6536/6536pro_001.html Which went something like this: $ INITIALIZE /STRUCTURE_LEVEL=5 $4$DKB100: SLAVESYSTEM Shouldn't that be /STRUCTURE_LEVEL=2 ? I guess that's what you did and 5 is a typo? $ MOUNT/FOREIGN $4$DKB100: $ BACKUP/LOG/CONVERT/IMAGE $4$DKC500: $4$DKB100:/NOINIT then shutdown the system, swapped $4$DKB0: and $4$DKB100: so the OSD-2 drive was now the single shadow set member, rebooted then issued a $ MOUNT/SYSTEM DSA0: /SHADOW=($4$DKB0:, $4$DKB100:) SLAVESYSTEM SYSTEM$ to bring $4$DKB100: (the old ODS-5 drive) back into the shadowset via copy. The ALPHA and VAX are now clustered nicely, including a common SYSAUTH and RIGHTSLIST, so I can now login to my normal account hosted on the ALPHA from the VAX. I've also pulled out common logicals and mounts into a common file. Good progress today. Good news that everything is working now. Regards, Peter Coghlan.