|We're trying to write to 60 meter DDS tapes that work fine in our DDS-1
|(or earlier) tape drive, but are not usable in the DDS-2 drive on our
|new machine.  These are genuine HP tapes, although they are not marked
|as "Media Recognition System" tapes.  The tape mounts and is recognized
|by the volume manager (I get the volume mounted message), but when I
|try to write to the tape, I get a "No Write Ring" message


As Jeff mentioned, the problem is using non-MRS media in DDS2 drives.

The good news is that you can override the "protection" of non-MRS media
if you really want to. On the bottom of the C1533 mechanism is an
8-position DIP switch. Position 3 controls the non-MRS write-enable
function. As shipped from the factory, position 3 is OFF, to disable
writing to non-MRS media. To write-enable the drive for non-MRS media,
power down the drive, change position 3 to ON, and turn the drive back
on.

This is only an issue for 60m and 90m DDS media; all DDS2 and DDS3 media
is MRS. Many DDS tapes are also MRS; look for the 4 vertical stripes/bars
next to the DDS logo, or the words "Media Recognition System" somewhere
on the casing.

Steve