For those itching to try, simh is capable of emulating a VAX and running OpenVMS (or NetBSD/vax) on them. One can also get a hobbyist license and media from HPE https://www.hpe.com/h41268/live/index_e.aspx?qid=24548, http://www.openvmshobbyist.com) and play around with it.

It is really quite a fascinating OS (I've had it running under a MicroVAX 4000/60 for fun -- and yes, I can truly say fun!) and feels quite modern even today.