PDP-11/20 and KE11 (was Re: 11/35 questions)

On Fri, Feb 8, 2013 at 1:41 PM, Dave McGuire <mcguire at neurotica.com> wrote: It will work in pretty much everything, AFAIK, since it's a peripheral not a "CPU extension". The KE11-A is functionally identical but built on the backplane peripheral model of the 11/20 and rare enough that I never figured on running across one I could get. I know that there's an occasional KE11-B running around since it's a single card. Me too. It's no big shake to run it on a real PDP-11 - as long as you have a KE11 of some kind in there _and_ you have matching peripherals for the 1972-era code. I haven't tried it, but I would be surprised to learn that you couldn't get v1 UNIX working on an 11/04 (peripheral issues aside). What I really want to do (and it sounds like you do too) is to run v1 UNIX not just on real iron, but the on the closest approximate I can manage of what was used in 1972. Step one is to get the 11/20 doing *anything*. Step two is to get the 11/20 running with RK05s. Then I can start to consider how I would either provide a register-compatible swap device or how much coding changes I'd have to tackle to get v1 code to use some _other_ swap device. Once I have a plan for how to provide swap, _then_ it's worth looking in all seriousness for a KE-11. Many steps to go before I have anything to purchase. Lots to fix and play with. -ethan