; DOS 3.31 Bios Parameter Block
bpb_ss:	  equ 0x00 ; WORD sector size
bpb_sc:	  equ 0x02 ; BYTE sector / cluster
bpb_rsc:  equ 0x03 ; WORD reserved sector count
bpb_fn:	  equ 0x05 ; BYTE fat number
bpb_rde:  equ 0x06 ; WORD root dir entries
bpb_ts:	  equ 0x08 ; WORD total sectors
bpb_md:   equ 0x0A ; BYTE media descriptor
bpb_sf:	  equ 0x0B ; WORD sectors / fat
bpb_spt:  equ 0x0D ; WORD sectors per track
bpb_nos:  equ 0x0F ; WORD number of sides
bpb_po:   equ 0x11 ; DWORD partition offset
bpb_lts:  equ 0x15 ; DWORD large total sectors

; DOS 4.0 Extended Bios Parameter Block
bpb4_dn:  equ 0x19 ; BYTE drive number
bpb4_sig: equ 0x1B ; BYTE 29h
bpb4_ser: equ 0x1C ; DWORD serial

; DOS 7.1 Extended Bios Parameter Block
bpb7_lsf: equ 0x19 ; DWORD large sectors / fat
bpb7_rdc: equ 0x21 ; DWORD root directory cluster
bpb7_fsc: equ 0x25 ; WORD fsinfo sector
bpb7_bsc: equ 0x27 ; WORD backup boot sector
bpb7_dn:  equ 0x35 ; BYTE drive number
bpb7_sig: equ 0x37 ; BYTE 28h or 29h
bpb7_ser: equ 0x38 ; DWORD serial

bpb_len:  equ 0x4F