STANDARD MICROSYSTEMS CORPORATION



     Microsoft WindowsNT FLOPPY.SYS Update

     This application note describes the pertinent modifications for the
     updated WindowsNT FLOPPY.SYS driver that will begin shipping from
     Microsoft in February of 1994.

     PROBLEM

     Diskette read errors reported with Microsoft WindowsNT and SMC37C66X
     Super I/O controllers.

     CAUSE

     The problem involves the interpretation of the "Seek End" flag (Status
     Register 0, Bit 5) by Microsoft's FLOPPY.SYS diskette driver. The
     SMC37C66X and Intel 82077 specifications both state that this bit
     should be set after an implied Seek command. Apparently, the 82077 does
     not always set this bit properly, and the original FLOPPY.SYS driver
     was developed to expect the unspecified response. DOS, OS/2, UNIX and
     other OS floppy interfaces mask this bit on implied seeks to maintain
     full compatibility. The upgraded WindowsNT driver includes this mask
     (requires one line of code). This ambiguity does not affect Explicit
     Seek commands.

     CORRECTIVE ACTION

     Microsoft Hardware Vendor Relations Group has been advised of this
     problem and has responded by incorporating the upgraded driver in the
     next version of WindowsNT to begin shipping in February, 1994. The new
     driver is currently available on SMC's Bulletin Board System,
     (516) 273-4936, and is being placed on Microsoft's Bulletin Board
     System, (206) 936-6735. This driver can be installed on current
     systems with the following procedure.

     WindowsNT with FAT File System

     1. Boot system with a DOS diskette
     2. Copy the updated FLOPPY.SYS over the existing one
     3. Remove DOS diskette and reboot under WindowsNT

     WindowsNT with Non-FAT File System (i.e. NTFS)

     1. Rename old FLOPPY.SYS to FLOPPY.OLD
     2. Copy new FLOPPY.SYS to hard disk

     If you have any further questions, please call our toll-free
     Applications number at 800-443-SEMI (Canadian and International
     customers can call 515-435-6000 and ask for Component Products
     Applications).