Hi At least for Dave's setup, he could get by with a bypass switch on the head selector. It is always funny what different setups have done. At least there is a potential bypass for this one. I'd guess the fellow that wrote the driver for the Kaypro didn't have a problem so he didn't notice the missing head information in the sector header. He may have thought the controller took care of this somehow. I know when I've fiddled with the disk controller directly, it isn't always clear when and where each register takes effect. There are a few places that it seem that there is redundant information. Dwight