Massbus simulation

Dave McGuire mcguire at
Wed Jun 20 13:50:47 CDT 2007

On Jun 20, 2007, at 11:44 AM, Ethan Dicks wrote:
>> > The 11/[750,780,785,790,795] has Massbus too.
>>    Well they *can*.  As can many PDP-11s.  So yes, I suppose you have
>> a point!
> I haven't tried to find an RH-11 recently, but an RH750 is a single
> card (no backplane required), with a simple cable arrangement from the
> 11/750 backplane to the I/O bulkhead area (theoretically, depending on
> how a modern Massbus device was constructed, one could even just run a
> trio of 40-pin cables between the 11/750 backplane and the new device,
> and bypass "real" Massbus cables).

   An RH-11 is a four-slot backplane full of cards.  And the most  
static-sensitive piece of DEC equipment I have *ever* seen.

> I would almost expect that every 11/780 that's still running these
> days has an RH780, but I doubt that's a very large pool of machines.
> At least 11/750s are small enough to run in a home/office environment.
> Even so, I'd think the most obvious consumers of a new Massbus
> storage device would probably be either the 11/70 crowd, or, more
> likely, the PDP-10 crowd.  I know I'd rather run a 3.5" IDE drive
> attached to some electronics than an RP07 for every-day use.

   Well I'd love to have one for my PDP-11/70, but at least I do have  
other disk options for it, so it's not as urgent.  The KS10, on the  
other hand, is a big paperweight without a TU45 and a MASSBUS- 
attached disk.

> I don't have hard numbers in front of me, but am of the opinion that
> there are enough hobbyists who would buy a new Massbus disk to make
> the effort worthwhile.

   Well, with VAXen in mind, I'd be inclined to agree...though it's  
not really that difficult to get non-MASSBUS disks on VAXen.

>   Of couse there are more who could use a Unibus
> disk, but that's no reason not to take a stab at Massbus.

   No, absolutely not...and I'd love to see it happen.


Dave McGuire
Port Charlotte, FL

More information about the cctalk mailing list