I just committed a basic Massbus device driver and driver for 
Massbus disks. The disk device driver needs some more work to
be complete, but works OK for now.
What is still missing:

- Standard DEC BAD144 bad block forwarding support.
- Ability to handle hard/soft read errors.
- Non-data transfer interrupts.

It works OK as long as you don't have any bad blocks on your disk
or don't get any read errors. I have used the device drivers
on RP06 and RP07 disk drives, and both of them has error-free
media so I haven't had any trouble.

-- Ragge