RA81 or RM05?

[FRANK%utah-20 at sri-unix.UUCP]

From:  Randy Frank <FRANK at utah-20>

Having talked to both people and DEC and Berkeley about potential support
for CI bus (HSC50) based disks, the comments can be summarized as follows:

1) writing a driver for a CI based disk is more akin to writing a networking
   system than writing a device driver.  In particular, you have to
   implement a protocol called MSCP (mass storage control protocol) which
   is used over the CI bus.

2) it isn't a trivial job (i.e., don't expect one from DEC in the next few
   weeks).  It's substantially harder that simply hacking an existing
   disk device driver for a "new" disk.

3) no one will commit that they actually are going to do it, but that clearly
   it is DEC's future architecture, so in most probability it will be done
   at some time in the future, but don't hold your breath.

4) (this one's my own interpretation) Ideally what DEC would like to do
   is have Unix and VMS co-exist on the same CI bus, hopefully sharing
   disk structures.  Clearly this is an enormous project, but given DEC's
   planned support of Vax Unix is probably an intelligent thing to do.
   Whether or not it is even a reasonable thing to implement remains to
   be seen.
-------