OSDev

fdc_out(fdpt->sec_size);
        fdc_out(fdpt->eot);
        fdc_out(fdpt->gap_rw);
        fdc_out(fdpt->dtl);

struct compat_floppy_struct {
      compat_uint_t   size;
      compat_uint_t   sect;
      compat_uint_t   head;
      compat_uint_t   track;
      compat_uint_t   stretch;
      unsigned char   gap;
      unsigned char   rate;
      unsigned char   spec1;
      unsigned char   fmt_gap;
      const compat_caddr_t name;
   };

 * This struct defines the different floppy types.
 *
 * Bit 0 of 'stretch' tells if the tracks need to be doubled for some
 * types (e.g. 360kB diskette in 1.2MB drive, etc.).  Bit 1 of 'stretch'
 * tells if the disk is in Commodore 1581 format, which means side 0 sectors
 * are located on side 1 of the disk but with a side 0 ID, and vice-versa.
 * This is the same as the Sharp MZ-80 5.25" CP/M disk format, except that the
 * 1581's logical side 0 is on physical side 1, whereas the Sharp's logical
 * side 0 is on physical side 0 (but with the misnamed sector IDs).
 * 'stretch' should probably be renamed to something more general, like
 * 'options'.  Other parameters should be self-explanatory (see also
 * setfdprm(8)).
 */
static struct floppy_struct floppy_type[32] = {
   {    0, 0,0, 0,0,0x00,0x00,0x00,0x00,NULL    },   /*  0 no testing    */
   {  720, 9,2,40,0,0x2A,0x02,0xDF,0x50,"d360"  }, /*  1 360KB PC      */
   { 2400,15,2,80,0,0x1B,0x00,0xDF,0x54,"h1200" },   /*  2 1.2MB AT      */
   {  720, 9,1,80,0,0x2A,0x02,0xDF,0x50,"D360"  },   /*  3 360KB SS 3.5" */
   { 1440, 9,2,80,0,0x2A,0x02,0xDF,0x50,"D720"  },   /*  4 720KB 3.5"    */
   {  720, 9,2,40,1,0x23,0x01,0xDF,0x50,"h360"  },   /*  5 360KB AT      */
   { 1440, 9,2,80,0,0x23,0x01,0xDF,0x50,"h720"  },   /*  6 720KB AT      */
   { 2880,18,2,80,0,0x1B,0x00,0xCF,0x6C,"H1440" },   /*  7 1.44MB 3.5"   */
   { 5760,36,2,80,0,0x1B,0x43,0xAF,0x54,"E2880" },   /*  8 2.88MB 3.5"   */
   { 6240,39,2,80,0,0x1B,0x43,0xAF,0x28,"E3120"},   /*  9 3.12MB 3.5"   */

   { 2880,18,2,80,0,0x25,0x00,0xDF,0x02,"h1440" }, /* 10 1.44MB 5.25"  */
   { 3360,21,2,80,0,0x1C,0x00,0xCF,0x0C,"H1680" }, /* 11 1.68MB 3.5"   */
   {  820,10,2,41,1,0x25,0x01,0xDF,0x2E,"h410"  },   /* 12 410KB 5.25"   */
   { 1640,10,2,82,0,0x25,0x02,0xDF,0x2E,"H820"  },   /* 13 820KB 3.5"    */
   { 2952,18,2,82,0,0x25,0x00,0xDF,0x02,"h1476" },   /* 14 1.48MB 5.25"  */
   { 3444,21,2,82,0,0x25,0x00,0xDF,0x0C,"H1722" },   /* 15 1.72MB 3.5"   */
   {  840,10,2,42,1,0x25,0x01,0xDF,0x2E,"h420"  },   /* 16 420KB 5.25"   */
   { 1660,10,2,83,0,0x25,0x02,0xDF,0x2E,"H830"  },   /* 17 830KB 3.5"    */
   { 2988,18,2,83,0,0x25,0x00,0xDF,0x02,"h1494" },   /* 18 1.49MB 5.25"  */
   { 3486,21,2,83,0,0x25,0x00,0xDF,0x0C,"H1743" }, /* 19 1.74 MB 3.5"  */

   { 1760,11,2,80,0,0x1C,0x09,0xCF,0x00,"h880"  }, /* 20 880KB 5.25"   */
   { 2080,13,2,80,0,0x1C,0x01,0xCF,0x00,"D1040" }, /* 21 1.04MB 3.5"   */
   { 2240,14,2,80,0,0x1C,0x19,0xCF,0x00,"D1120" }, /* 22 1.12MB 3.5"   */
   { 3200,20,2,80,0,0x1C,0x20,0xCF,0x2C,"h1600" }, /* 23 1.6MB 5.25"   */
   { 3520,22,2,80,0,0x1C,0x08,0xCF,0x2e,"H1760" }, /* 24 1.76MB 3.5"   */
   { 3840,24,2,80,0,0x1C,0x20,0xCF,0x00,"H1920" }, /* 25 1.92MB 3.5"   */
   { 6400,40,2,80,0,0x25,0x5B,0xCF,0x00,"E3200" }, /* 26 3.20MB 3.5"   */
   { 7040,44,2,80,0,0x25,0x5B,0xCF,0x00,"E3520" }, /* 27 3.52MB 3.5"   */
   { 7680,48,2,80,0,0x25,0x63,0xCF,0x00,"E3840" }, /* 28 3.84MB 3.5"   */

   { 3680,23,2,80,0,0x1C,0x10,0xCF,0x00,"H1840" }, /* 29 1.84MB 3.5"   */
   { 1600,10,2,80,0,0x25,0x02,0xDF,0x2E,"D800"  },   /* 30 800KB 3.5"    */
   { 3200,20,2,80,0,0x1C,0x00,0xCF,0x2C,"H1600" }, /* 31 1.6MB 3.5"    */
};

...

      if (!_floppy) { /* Autodetection */
         if (!probing){
            DRS->probed_format = 0;
            if (next_valid_format()){
               DPRINT("no autodetectable formats\n");
               _floppy = NULL;
               REPEAT;
            }

/* checks drive geometry - call this after any disk change */
BOOL log_disk(DrvGeom *g)
{
   /* get drive in a known status before we do anything */
   reset();

   /* assume disk is 1.68M and try and read block #21 on first track */
   geometry.heads = DG168_HEADS;
   geometry.tracks = DG168_TRACKS;
   geometry.spt = DG168_SPT;

   if (read_block(20,NULL)) {
      /* disk is a 1.68M disk */
      if (g) {
    g->heads = geometry.heads;
    g->tracks = geometry.tracks;
    g->spt = geometry.spt;
      }
      return TRUE;             
   }
   
   /* OK, not 1.68M - try again for 1.44M reading block #18 on first track */
   geometry.heads = DG144_HEADS;
   geometry.tracks = DG144_TRACKS;
   geometry.spt = DG144_SPT;

   if (read_block(17,NULL)) {
      /* disk is a 1.44M disk */
      if (g) {
    g->heads = geometry.heads;
    g->tracks = geometry.tracks;
    g->spt = geometry.spt;
      }
      return TRUE;
   }
   
   /* it's not 1.44M or 1.68M - we don't support it */
   return FALSE;
}