I have no idea how much work would be involved in
adding a 516 mode to
SIMH, nor how hard it would be to simulate the bit-serial IMP-host
interface hardware, but I'd certainly be game to help with that.
The 516 and the 316 are 100% code compatible. Just the cycle time
differs (0.96us for the 516, 1.3us for the 316 IIRC)
Adrian
http://www.series16.adrianwise.co.uk