Each OpenDevice() must eventually be matched by a call to CloseDevice().

All I/O requests must be complete before CloseDevice().  If any requests
are still pending, abort them with AbortIO().

    if (!(CheckIO(ConsIO)))
        AbortIO(ConsIO);    /* Ask device to abort any pending requests */

    WaitIO(ConsIO);         /* Wait for abort, then clean up */
    CloseDevice(ConsIO);    /* Close console device */