JSI Tip 1861. 'STOP: The disk media is not recognized, it may not be formatted'.

You receive the subject message when you attemp to access a floppy disk.

Windows NT requires a media descriptor byte. Some preformatted diskettes don't have a media descriptor byte.

The workaround is to format the diskette in Windows NT.

Some programs, such as NORTON DISKEDIT can change the media descriptor byte, which is located at byte 21 (0x15) of sector 0, counting from 0. Here is a table of media descriptor bytes:

 
   Byte   Capacity   Media Size and Type
   -------------------------------------------------

   F0     2.88 MB    3.5-inch, 2-sided, 36-sector
   F0     1.44 MB    3.5-inch, 2-sided, 18-sector
   F9     720K       3.5-inch, 2-sided, 9-sector
   F9     1.2 MB     5.25-inch, 2-sided, 15-sector
   FD     360K       5.25-inch, 2-sided, 9-sector
   FF     320K       5.25-inch, 2-sided, 8-sector
   FC     180K       5.25-inch, 1-sided, 9-sector
   FE     160K       5.25-inch, 1-sided, 8-sector
   FE     250K       8-inch, 1-sided, single-density
   FD     500K       8-inch, 2-sided, single-density
   FE     1.2 MB     8-inch, 2-sided, double-density
   F8     -----      Fixed disk