Compatibility: 2.0+
Expects: AH    54H
                                                                  
Returns: AL    current state: 00H is OFF
01H is ON
                                                                  
Info: Returns the current DOS disk write verification state.  If AL
returns as 01H, then DOS will check the CRC of each sector that
it writes, verifying that data was written correctly.

Notes:   Programs can use Fn 2eH to set or reset the verification state.
  The DOS Verify command can be used to change the state.

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DOS Fn 54H: Get DOS Verify State