The RX01 used the DX driver and the RX01 used the DY driver. If the driver on the floppy does not match the actual drive, it will not boot. So, a normal RX01 floppy will not boot in an RX02 drive and vice versa. However, I THINK that if you used the wrong density floppy but put the right driver on it (An RX01 floppy with the DY driver as the boot driver) it will work, but that is not how the distributions were set up. Of course there are games you can play, like toggling in a bootstrap, but I don't think that was being asked. Well, anyway, that is what I remember of it, please, anyone, correct me if I'm wrong. Joe Heck