Well, there's the brief summary: http://www.seagate.com/cgi-bin/view.cgi?/mfm/st412.txt If you want a really good rundown on the interface, here's one, unfortunately in Lithuanian: http://www.ik.ku.lt/lessons/konspekt/kompArch/referaty/Disk_kaupikliai2.htm Your biggest problem is going to be providing the serial raw data stream support. That is, taking fully-decoded data and providing a high-speed serialized MFM signal for reading and doing the reverse for writing. It's usually a lot simpler if you can ditch the old MFM controller and tie in a modern IDE drive directly. Cheers, Chuck On 5/19/2006 at 5:19 PM Kelly Leavitt wrote: