<> Yup. RD53 is an RLL 40 meg, I think. Not very reliable in my experience <> Somewhere on the system is probably a tk50 tape drive, too. Slow and not <> very high density per cartrige, but they work. BZZT! RD53 is MFM 70mb (100mb if RLL) and only old ones are unreliable... then again a new one is far from likely. They were reliable but the typical operational life was about 4 years (100% powered on). After that they tended to decay. For that time (late 80s) 35,000 power on hours was pretty good though not exceptional. the problem is the last ones were manufactured some 8 or more years ago! <As a matter of fact, the DB15F does have the interlocks found in AUI's. Nominal configuration, AUI for DEQNA or DELQA. Things to check, if either box make sure the fans work, they are needed! If its a BA123 end table box then there are three fans, they must all work or bad things happen. Then check the power supply cables if the box is BA23 (narrow one) as they have been known to melt at the bus or PS connectors. Generally this things are hard to kill and run well. VMS is available VIA DECUS hobbiest liccense for free. You can use any media you can find and versions to 7.2 (one older than current). Montagar sells a CD with VMS and various other tools included. If unix is you favorite then Netbsd is an ongoing project but the MVII port is reputed to be functional. I run two of them one in BA23 and the other in the larger ba123. Allison