struc BootSector
 bsJump         db 3 dup (?)    ; E9 XX XX or EB XX 90
 bsOemName      db "????????"   ; OEM name and version
                               ;; Start of BIOS parameter block
 bsBytesPerSec  dw ?            ; Bytes per sector
 bsSecPerClust  db ?            ; Sectors per cluster
 bsResSectors   dw ?            ; No. of reserved sectors
 bsFATs         db ?            ; No. of file allocation tables
 bsRootDirEnts  dw ?            ; No. of root-directory entries
 bsSectors      dw ?            ; Total no. of sectors (0 if > 32 MB)
 bsMedia        db ?            ; Media descriptor
 bsFATsecs      dw ?            ; No. of sectors per FAT
 bsSecPerTrack  dw ?            ; Sectors per track
 bsHeads        dw ?            ; No. of heads
 bsHiddenSecs   dd ?            ; No. of hidden sectors
 bsHugeSectors  dd ?            ; No. of sectors if bsSectors = 0
                               ;; End of BIOS parameter block
 bsDriveNumber  db ?            ; Drive no. (80h=1st hard disk, else 0)
 bsReserved1    db ?            ; Reserved
 bsBootSignature db ?           ; Extended boot signature (29h)
 bsVolumeID     dd ?            ; Volume serial number
 bsVolumeLabel  db 11 dup (?)   ; Volume label
 bsFileSysType  db 8 dup (?)    ; File-system type (e.g. "FAT12   ")
ends

;       The BootSector structure contains information about the disk
;       (or other storage medium) for a particular drive. The
;       structure appears at the beginning of the first sector (the
;       boot, or startup, sector) of the disk.
;       The BootSector structure shares the first sector with the
;       bootstrap routine and the boot sector signature. The boot
;       sector signature, stored in the last two bytes of the sector,
;       must be 0AA55h.