This is pretty cool. I have OpenVMS VAX 7.3 running under SIMH clustered with OpenVMS Alpha 8.3 running under FreeAXP. I'm using bridged TAP network adapters for each of them. DECnet, TCP/IP, LAT, cluster comms all seem to work fine so far.
BTW, I notice that FreeAXP can also mount SIMH disks, so I gather they use the same simple container format. (Of course, I don't do that while they're also mounted via clustering I know what havoc that would cause.)
FreeAXP reports about 198 EUP while pegging one processor at 100% on my 4GHz Core I7. If one EUP is honestly 700K instructions per second, then that's about 138M instructions per second. Not exactly the supposed 166M of the real thing, but not bad. However, I did give up on having TCPIP$CONFIG generate an SSH key. I didn't want to wait for it...
A VAX under SIMH can have 512M of memory, but a poor Alpha under FreeAXP is limited to a measly 128M. I gather it's going to be doing a lot of paging.
SIMH can detect when VMS is idle when emulating a VAX, but I gather FreeAXP cannot do so when emulating an Alpha. I seem to recall dim memories of idle being totally different between VAX and Alpha (or was that an even earlier VMS internals change that I'm dimly recalling)? FreeAXP constantly pegs one processor at 100% usage, even when idle. Can anything be done about that?
