Function 0BH (11): Flush Output Buffers

The flush-output-buffers function applies only to character devices, and in block-device drivers it should do nothing except set the done flag. This function empties the output buffer, if any, and discards any pending output requests.

The flush-output-buffers function is called with

RH + 2 BYTE Command code = 11 (0BH)

It returns

RH + 3 WORD Status