Well, I think I got this off of GEnie, but it didn't come with any documentation except for whats in the program. What this program does is let you use Ultraspeed from hte US doubler with DOS 2.5 and MyDOS. (Actually, the prg doesn't say anything about MyDOS, but it works just fine with it, even in double density mode.) The way I went about setting up MyDOS was different then what the prg says to do. I booted up SpartaDOS, and used SCOPY to copy my MyDOS boot disk onto a disk with ultraspeed with the following parameters: D1:SCOPY D1: D1: /U You then run the program on the resulting disk, and viola, fast speed with MyDOS. (Or Dos 2.0/2.5)