This table says the maximum version supported of OpenVMS VAX on the
MicroVAX I is v5.1-1
http://h71000.www7.hp.com/openvms/hw_supportchart.html
Anyone know if later versions still work while being technically not
supported, or if later versions no longer work on a MicroVAX I? Even
maxed out at 4MB I image it wouldn't be too fun to use.
I suppose as a collectors item it might be more interesting to keep
them configured as a MicroVAX I / VAXstation I as those are probably
more rare these days than anything newer, but if you actually wanted
to do anything with them it would probably be a lot more fun to swap
out the CPU and memory for a KA630 / KA650 / KA655 set and those
shouldn't take much to find if you ask around.