On 12/31/2013 01:03 PM, John Wilson wrote: When do you say it hangs, do you mean it's looping (executing PDP-11 code -- might be worth seeing what and/or looking at the stack to see how it got there), or that the bus is hung and the CPU is stuck? I didn't investigate to that level. I just figured I'd fire the question at the gang here since it'd been so long since I'd messed with RSX. The hardware is, as far as I can tell, otherwise fine. I built the system up from parts a few weeks ago, and have exercised it with RT-11. The order of dependence on strictly working (and/or accurately emulated) hardware goes: RT => RSX => RSTS. So the fact that something works with RT proves *nothing*! (I've learned this the hard way so many times.) Indeed...I've been bitten by that a few times as well. Like this time. ;) Of course, looked at another way, it's nice of RT to be willing to run on hardware that's not long for this world... True. ;) -Dave -- Dave McGuire, AK4HZ New Kensington, PA