There's a nice UDA/KDA emulation that uses SD cards or basically anything on the Linux side. I helped Dave Plummer (Dave's Garage fame) get it working with 2.11BSD on an 11/85 as a second KDA which 2.11 did not want to do. I suspect that's the way to go these days. He has it emulating RA92's and a few other things. Since this is more about HW than UNIX specifically, we should take it off line.

Clem

On Mon, Jun 9, 2025 at 4:40 PM Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote:

> From: Vicente Collares

> I'm more interested in its historical signaficance.

If that's your interest, PDP-11's are absolutely _the_ way to go. The PDP-11
is _the_ machine that made UNIX. That choice has good points, and a very bad
point, though.

Good points are that QBUS PDP-11's are pretty easy to find, pretty small
(desktop PC-sized), and not very expensive. They're pretty robust, too - I
have a large stack of PDP-11 QBUS CPUs, and none of them had failed, as of the
last time that I powered them on.

The very bad point is that working mass storage for them is very hard to
find. The controllers are around, but not the drives.

Does anyone know if anyone is making a QBUS mass storage clone? Bridgham and
I were going to produce QBUS RK11/RP11 clone that used SD cards to hold the
bits. We got the prototype working, and it booted UNIX, but then I came down
with COVID and post-COVID myalgic encephalomyelitis, and that was the end of
that.

Noel