Device Request 0aH: Output Status

 This tells the driver to return its output status; in particular, to
 indicate whether an output request can be satisfied without waiting.

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   +0      1  bLen         0dH (length of this request packet)
   +1      1  bUnitNo      (not used)
   +2      1  bCmd         0aH (command code)
   +3      2  rStatus      OUTPUT: Device Status Word must fill before exit
   +5H     8  res          (reserved)
          13               size of this structure

     rStatus  On exit, the driver must place a DevStatusWord here.  Always
              set the Done bit (bit 8).

              If the driver is unable to accept any additional characters,
              set the Busy bit (bit 9).  Otherwise, clear bit 9 to indicate
              that a call to DvRq 08H will be satisfied without waiting.

   Notes: ■ Output devices can be optimized by processing DvRq 10H (output
            until busy).

See Also: Device Requests
          Installable Device Drivers