It's a $20 shareware (free download, and not crippled) CNC control package. It's DOS based, and is HIGHLY configurable through a turbocnc.ini file. Not terribly unfriendly, either.
There are also a lot of other choices, some of which advertise on the top of the forum pages...FreeMill, I think, is another, and Mach1 is good, and EMC is one that runs under LINUX but will control anything at all.
Just look around...you'll find all sorts of options.
-- Chuck Knight