This tells the driver to return its output status; in particular, to
indicate whether an output request can be satisfied without waiting.
+0 1 bLen 0dH (length of this request packet)
+2 1 bCmd 0aH (command code)
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