I think my statement is entirely unrelated to your question. The Apple ][ DOS 3.2/3.3 sector format, while it follows conceptually the same ideas as the IBM 3740 standard in that they are both ways of recording blocks of data on floppy disks and both encode the track and sector number in the header, is not by any stretch compatible with it. On an Apple Disk ][, you have complete control over the stepper phases, so quarter- and half-tracking is possible. (You can also blow out the Apple's power supply by switching the phases on and off at a certain "bad" rate, too!) The 34-pin Shugart SA400-style interface used for floppies in PC's doesn't allow half- or quarter-track stepping, though you could imagine trying to read or write something while rapidly stepping in/stepping out. If you want more information, I highly recommend that you read the Shugart SA400 interface documents, or the interface documents of a drive with a similar interface (i.e. the TEAC datasheets, which are also very complete.) I don't know of any documentation of the Macintosh 3.5" floppy interface. If someone could point me towards the relevant documents (or even the part numbers they claim to describe) I'd be quite happy! -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927