Ming_Mae wrote: If you're talking about using drives with the ST506/ST412 interface, you most certainly can use an "RLL drive" (e.g., ST277R) on an MFM controller. Of course, you'll only get 2/3 the capacity that you would get with an RLL controller. Using an "MFM drive" with an RLL controller often works, but it depends a lot on the drive. In my experience high-quality drives like the Maxtor XT1000 and XT2000 series always worked fine. Eric