the Only VMS post on fixya ever.
wow. from the dark ages of DEC. VMS. OS.
sounds like bad drive if it can not be mounted.(or disk bad)
sounds like you are 42 years behind the upgrade curve too...
i used to work on all DEC systems. so know that . 1975
the DS10, is now 18 years old.
here is a relic manual, on that
is this your only DS10, of not try the drive on system #2?
ahh its now called OPENVMS,, amazing thing that is.
open vms was ported to ALph chips. 1992
then 2001 port of OpenVMS to the Intel Itanium
so it's an 17 year old OS.
get HP proliant Server G7 up. and win. for sure.