Detecting XBIOS Resident in the System

;**********************************************************************
;* XBIOS Identify Command 
;* The following code checks for the presence of XBIOS
;**********************************************************************
    mov   ax,0f900h
    mov   dx,80h
    int   13h
    jc    xbios_driver_not_resident
    test  dx,8000h
    jz    xbios_driver_not_resident
;Ontrack XBIOS driver is resident