PRT_LINE x1k12                                  ͻ
 DISK 
                                  ͼ
        Single or Double Side   (0 and 1)
        80 Tracks               (0 to 79)
       ~6250 bytes/track        (Capacity 500,000 or 1,000,000 bytes/disk)
        Speed ~300 rpm

1Ŀ
                          TRACK STRUCTURE                                TOS 
Ĵ
 START OF TRACK  Gap               ~$4E ~$4E ... 32 mini ... ~$4E ~$4E   60 
Ĵ
 SECTOR          Synchro   $00 $00 ... 8 mini ... $00 $00 ~$A1 $A1 $A1   12 
                 Index Address Mark                                $FE      
                 Track number                                     0-79      
                 Side number                                       0-1      
                 Sector number                                     1-n  1-9 
                 Sector length in bytes                         0: 128      
                                                                1: 256      
                                                                2: 512    2 
                                                                3:1024      
                 Cyclic Redundancy Checksum                    $SS $SS      
                 Gap                        $4E $4E ... 22 ... $4E $4E      
                 Synchro       $00 $00 ... 12 ... $00 $00 ~$A1 $A1 $A1      
                 Data Address Mark                             $FB/$F8  $FB 
                 Data         $XX $XX ... 128/256/512/1024 ... $XX $XX  512 
                 Cyclic Redundancy Checksum                    $SS $SS      
                 Gap               ~$4E ~$4E ... 24 mini ... ~$4E ~$4E   40 
Ĵ
 ANOTHER SECTOR   etc...                                                  9 
Ĵ
 END OF TRACK    Gap               ~$4E ~$4E ... 16 mini ... ~$4E ~$4E  664 

                            Ŀ
                             TOS SECTOR ASSIGNMENTS 
               Ŀ
                       Physical Sector  Track          Single   
               Ŀ   Ĵ           
                             Cluster     Side       Side Disk 
               Ŀ       Ĵ
                  Logical Sector         Track     Double   
               Ŀ             Ĵ           
                Contents                  Side  Side Disk 
               
                Boot sector    0  -1 00 00
               Ĵ
                FAT 1          1  -2 00 00
               Ĵ
                FAT 1          2  -3 00 00
               Ĵ
                FAT 1          3  -4 00 00
               Ĵ
                FAT 1          4  -5 00 00
               Ĵ
                FAT 1          5  -6 00 00
               Ĵ
                FAT 2          6  -7 00 00
               Ĵ
                FAT 2          7  -8 00 00
               Ĵ
                FAT 2          8  -9 00 00
               Ĵ
                FAT 2          9  -1 10 01
               Ĵ
                FAT 2         10  -2 10 01
               Ĵ
                Directory     11  -3 10 01
               Ĵ
                Directory     12  -4 10 01
               Ĵ
                Directory     13  -5 10 01
               Ĵ
                Directory     14  -6 10 01
               Ĵ
                Directory     15  -7 10 01
               Ĵ
                Directory     16  -8 10 01
               Ĵ
                Directory     17  -9 10 01
               Ĵ
                Data          18  21 20 10
               Ĵ
                Data          19  22 20 10
               Ĵ
                Data          20  33 20 10
               Ĵ
                Data          21  34 20 10
               Ĵ
                Data          22  45 20 10
               Ĵ
                Data          23  46 20 10
               Ĵ
                Data          24  57 20 10
               Ĵ
                Data          25  58 20 10
               Ĵ
                Data          26  69 20 10
               Ĵ
                Data          27  61 30 11
               Ĵ
                Data          28  72 30 11
               Ĵ
                Data          29  73 30 11
               Ĵ
                Data        ..............
               Ĵ
                Data         7193529790391
                Data        14397129   791
               
2                           Ŀ
                            BOOT SECTOR 

 Byte#          Designation
-------         --------------------------------------
    0-1         0 or BRA.S address in this boot sector
    2-7         Free text of 6 bytes
   8-10         Disk serial number on 24 bits
  11-12         #Bytes   per  sector   =     512 |                    (Low-High)
     13         #Sectors per cluster   =       2 |
  14-15         #Reserved sectors      =       1 |                    (Low-High)
     16         #File Allocation Table =       2 |
  17-18         #Elements in directory =     112 |  BIOS              (Low-High)
  19-20         #Sectors               =720/1440 |  PARAMETER         (Low-High)
     21         Media descriptor       = $F8/$F9 |  BLOCK
  22-23         #Sectors per FAT       =       5 |                    (Low-High)
  24-25         #Sectors per track     =       9 |                    (Low-High)
  26-27         #Sides                 =     1/2 |                    (Low-High)
  28-29         #Hidden sectors        =       0 |                    (Low-High)
 30-509         -
510-511         2 Bytes for adjust checksum of 256 words of bootsector
                to reach $1234 for executable bootsector
                      Ŀ
                       FILE ALLOCATION TABLE 

        12 bits (3 nibbles) for each cluster with this code:
     $000:Free cluster
     $FF7:Bad  cluster
     $HML:Next cluster              (H:High nibble M:Middle nibble L:Low nibble)
     $FFF:End  cluster

Logical:    -       -  Cl.2    Cl.3    Cl.4    Cl.5    Cl.6    Cl.7    ...
         $FF7    $FFF  H2M2L2  H3M3L3  H4M4L4  H5M5L5  H6M6L6  H7M7L7

Physical: $F7 $FF $FF  M2L2 L3H2 H3M3  M4L4 L5H4 H5M5  M6L6 L7H6 H7M7  ...
                           Ŀ
                            DIRECTORY 

There are 112 entries of 32 bytes each.

 byte#
   0-7  Name                                         (   0:not used            )
                                                     ("."0:root directory      )
                                                     (". ":current subdirectory)
                                                     ("..":parent  subdirectory)
                                                     ( $E5:erased              )
  8-10  Extension
    11  Type           b5=archive bit
                       b4=subdirectory
                       b3=volume label
                       b2=system file
                       b1=hidden file
                       b0=read only file
 12-21   -
 22-23  Hour      b15-b11=hours
                   b10-b5=minuts
                    b4-b0=seconds

 24-25  Date       b15-b9=year-1980
                    b8-b5=month
                    b4-b0=day

 26-27  Starting cluster                                              (Low-High)
 28-31  Length                                              (Low-Midl-Midh-High)
