On 11/29/2016 06:51 PM, Noel Chiappa wrote: I'll add my penny... The likelihood of success is based on available money and space to store things. That and how common they were/are. For example a PDP-6, I believe under 30 were made so finding one is very unlikely and also going to be expensive to acquire never mind restore. So Unibus PDP-11s, they were largely going away by the late 70s to mid 80s with maybe 15000 made where Qbus 11s were ramping up from about 76 on though relatively recently with something north of 50,000 made. Easier to find and fix too as they used parts that aren't quite as extinct. Its also good that the early MicroVAX used the same bus and IO boards to add to the supply. Same would apply to the PDP-5, 12 and later its follow on the PDP8. The Omnibus 8s are easier to find and fix compared to the 8I/L and earlier machines, less costly too. There are other machines like Data General to consider as well. Or likely things that were common in your geography. Me, I've only been collecting since the mid 70s so patience has been an aid. Allison