reqpktptr          dd ?

rNulDevHdr         EQU 18
nulpfNextDev       dd 0ffff0000h        ; FAR Address of next device in chain
nulrDevAttr        dw 1000000000000100b ;
nulpnStrategy      dw _nul_strategy    ; Offset address of device strategy routine
nulpnInterrupt     dw _nul_interrupt   ; Offset address of device interrupt routine

nulabDevName       db 'NUL     ' ; Blank-padded device (or 10-byte block device sub-unit number)
nul                db 'NUL', 0
nuldevice proc far
; NUL Device Strategy
_nul_strategy:
        mov  word ptr [cs:reqpktptr], bx
        mov  word ptr [cs:reqpktptr+2], es
        retf
_nul_interrupt:
        push es
        push bx
        les  bx, [cs:reqpktptr]
        or   word ptr es:[bx+3], 100h  ; set done flag
        pop  bx
        pop  es
        retf
          ret
nuldevice endp


clock$    db 'CLOCK$',0
clockdriver proc far

          ret
clockdriver endp

console         db 'CON', 0

auxillary       db 'AUX', 0


