INT 15 C - OS HOOK - DEVICE OPEN (AT,XT286,PS)
        AH = 80h
        BX = device ID
        CX = process ID
        CF clear
Return: CF clear if successful
            AH = 00h
        CF set on error
            AH = status
                80h invalid command (PC,PCjr)
                86h function not supported (XT)
Note:   this function should be hooked by a multitasker which wishes to keep
          track of device ownership; the default BIOS handler merely returns
          successfully
SeeAlso: AH=81h,AH=82h

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