struc OpenCloseRequest          ; Device-Driver functions 0Dh, 0Eh
 ocrLength      db ?            ; Length of structure, in bytes
 ocrUnit        db ?            ; Unit number (block device only)
 ocrFunction    db ?            ; Function number (0Dh or 0Eh)
 ocrStatus      dw ?            ; Status
 ocrReserved    db 8 dup (?)    ; Reserved
ends                            ; = 13d bytes