CHS value field layout

• • hhhhhhhh CCssssss cccccccc
  • C = Cylinder, 10 bits range 0 .. 1023
  • H = Heads, 8 bits range 0 .. 254
  • S = Sectors, 6 bits range 1 .. 63
  • • Head value 255 normally not used (DOS/BIOS bug)
    • Sector value 0 is illegal, numbering is 1-based (cylinder and head are both zero-based)
  • CHS values are NOT really used anymore, but are often CHECKED by partitioning tools