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 */