On 06/07/2012 07:10 AM, Jordi Guillaumes i Pons wrote: Will pre-5.0 VMS run on a 4000-90? I don't recall when NVAX CPU support was added to VMS. I don't think so. I've built a 4.7 system running in a 11-780 SIMH emulator :) I doubt 4.7 would run even in my 3300 (my oldest real machine). I was still running 4.7 on one machine (11/750) when I installed my first 3100. I'm pretty sure I installed 5.0 on the 3100 though. I was already running 5.0 on a pair of MicroVAX-3600s, and then 5.1 came out very shortly thereafter. BTW, 4.7 boots so fast under SIMH than at first I thought it had somehow crashed or hung. When I got the "username:" prompt after pressing return I was amazed :) Nice. :-) I bet 4.7 would absolutely scream on a 4000-90 if it had CPU support. The difference between 4.7 and 5.0 on a 2.8VUP MicroVAX-III is like night and day...I can only imagine it on a 4000-90, more than ten times faster! -Dave -- Dave McGuire, AK4HZ New Kensington, PA