On Mon, Feb 27, 2017 at 11:32 PM, Josh Dersch <[email protected]> wrote: > Hi all - > > Anyone have any technical information (manuals, schematics, etc.) for the > DEC DW11 UNIBUS->QBus interface? I'm curious to know what it's capable of > and what the requirements are, especially on the QBus side of things. What > kind of backplane is required? I assume it doesn't support 22-bit QBus > devices given the age of the interface (and the complexity required to do > so), but does it handle 18-bit devices, or only 16?
I saw one in a PDP-11/34 at a Physics Lab at Ohio state in the early 1990s. It was in there so that they could use an IBV11 IEEE-488 interface with a Unibus machine. AFAIK, it's 18-bit not 16-bit. 22-bit Qbus wouldn't be directly controllable from a Unibus anyway (machines like the 11/44 that can address more than 256MB of memory have Unibus mapping registers that take care of RAM addressing, but the Unibus is still always 18-bit). The DW-11 came with a 4-slot hex Qbus backplane, a DDV11-CK, I'm fairly certain it was, that mounted directly in the BA11-K box, right next to a DD11-DK and a DD11-PK that were the Unibus slots for the CPU and memory. I've always wanted to see if it would work with a Qbus SCSI controller since Unibus SCSI controllers are far, far less common. -ethan
