While not helping your situation much, it's not inconceivable that very
modern disks may not work on DECstations.  We recently ordered some
RZ25Ls for swap disks from DEC and got RZ25Ns instead.  These failed
to even show up on a 'cnfg 3' from the PROM prompt.  We didn't have a
chance to find out what the problem was (it was a production site, and
we just shipped the disks back and got RZ25Ls instead).

Simon.