[Simh] VAX emulation issues on Raspberry Pi

[Robert Armstrong]

>My Raspberry Pi 2 clocks in at about 1.6 VUPS, my ESXI host is a 
>i7-3770 CPU @ 3.40GHz (which is starved for RAM), SIMH/VAX on a VM 
>running on it clocks in at about 34.6 VUPS.  I have a i5-3470 @ 3.2Ghz 
>and SIMH runs at about 31.6 VUPS

  FWIW, this may also say something about the quality of the code generation in gcc for ARM vs x86 processors, or it may even say something about the relative efficiency of those two architectures.

  I run a MicroVAX-3900 simh on an Intel Atom D525 based server continuously.  There are lots of little, fanless, 12V powered (for UPS) Atom based servers out there, and they're pretty cheap and low power.  I think mine averages about 10W, and that includes the SSD and the fan I had to stick in it because it got too hot in the network closet :-)

  Empirically, just sitting there using the simulation, it feels about as fast as a real MicroVAX-II or III.  Logging in via ssh, assuming you're using public key/private key authentication, does take forever to do the initial key exchange but once you're authenticated it's not bad.

Bob