struc BuildBPBRequest           ; Device-Driver function 02h
 bbrLength       db ?           ; Length of structure, in bytes
 bbrUnit         db ?           ; Unit number
 bbrFunction     db ?           ; Function number (02h)
 bbrStatus       dw ?           ; Status
 bbrReserved     db 8 dup (?)   ; Reserved
 bbrMediaID      db ?           ; INPUT:  media descriptor
 bbrFATSector    dd ?           ; INPUT:  buffer with first FAT sector
 bbrBPBAddress   dd ?           ; OUTPUT: BPB address
ends                            ; = 22d bytes