On 2013-07-15 16:37, Clem Cole wrote: Unibus to SCSI is probably your best bet. http://bitsavers.trailing-edge.com/pdf/cmd/CDU-720_May92.pdf These are available on eBay for about a $1K last I looked. You'll need to poke around the VMS web sites for the drivers, but we had some of these on a couple Unibus machines, including a 780 a >>long<< time ago. I know no reason why it would work for a 730 - although you might need to sysgen on a working system to create the boot disk. Something like a CDU-720 will work just fine. Normal MSCP, so no special device drivers needed either. Works fine in an 11/730, or any Unibus machine in fact. Bootable on just about anything as well. Johnny On Mon, Jul 15, 2013 at 10:21 AM, Bob Armstrong <bob at jfcl.com <mailto:bob at jfcl.com>> wrote: My 11/730 is not happy the electronics work great and are even fairly easy to fix, but keeping disk drives on the thing working is proving to be a challenge. Right now it has two RA81s and one has quit completely ( servo fine position error ) and the other is flaky. The original R80 on the RB730 had the HDA die years ago and I ve never been able to find a replacement.____ __ __ I have several vintage SMD drives, including a couple of nice CDC 9715 drives, that I was thinking about using to replace the RA8x drives. I have not one but two UNIBUS SMD controllers an Emulex SC21 and a Spectra Logic 121 that I thought would do the job, but after reading the fine print yesterday that turns out not to be true. Both controllers emulate RH11s with RM0x drives attached, which is fine if you re a PDP-11 but VMS has never supported that configuration.____ __ __ [Before anybody says Wait RM05s are supported by VMS, that s only partly true. VMS supported MASSBUS disks on a RH750 or RH780 controller, but VMS has never supported the RH11. Emulex actually sold a special VMS driver for their card, but I don t have it and besides, VMB still wouldn t support it. The Spectra Logic manual only talks about PDP-11 OSes and carefully avoids ever mentioning VMS.]____ __ __ I ve got some RA7x drives, but there s no easy way to mount them or supply power to them. I m not sure if there ever was a rack mount chassis for RA7x drives. There was for RA9x drives, but those I don t have. I also have two RC25 drives and several AZTEC controllers, but those drives were horribly unreliable even when they were new. Neither works, and fixing them or getting removable media for them is hopeless.____ __ __ Does anybody have any other ideas? Who else has an old UNIBUS VAX? What are you doing to disk drives? ____ __ __ I ve actually had the 11/730 for about fifteen years now I restored it out of parts from two different 730s that were scrapped. It s been fairly easy to keep running except for the drives, and although it s admittedly a bit slow, it s a cool machine.____ __ __ Bob____