The SoftDMC firmware does not support steppers, so this is a servo only deal. Besides, there are plenty of great options for steppers already out there.
An analog VFD spindle would use an axis.
There is no such thing as inexpensive Galil controllers on eBay. Those days are long gone. People saw them selling and started jacking the price up. Now there are auctions that start the bidding for a DMC-1040 ISA (useless to us) at $250.00 !!! And one guy wants ~2600.00 for a 2 axis DMC-2100 controller!!!
5i20, 5i23, and 7i43 via USB. These are the cards I have. And it one point, I had tested them all. The 5i22 is in the works as soon as there is a SoftDMC for it from Mesa. It may already have one by now. I guess I need to talk to Peter to find out.
I know that it runs on XP, as that is what I developed it on. But it should work on any 32bit system that Mach runs on.
The encoders will read back to Mach. It's functionally equivalent to the Galil plugin. I don't know about the dspmc, as I have never run one.
Steve