DOS Fn 440dH CL=67H: IOCTL Query Access Flag

                                             Compatibility: 4.0 only ◄Undoc► 
 Expects: AX    440dH
          BX    drive (0=default, 1=A, 2=B, etc.)
          CL    67H
          CH    08H (device category: block device)
          DS:DX addr of a 16-bit buffer to receive information
          ──────────────────────────────────────────────────────────────────
 Returns: AX    error code  if CF is set to CY
          DS:DX buffer contains returned data:
                DS:[DX+0]  always 0
                DS:[DX+1]  00H=drive is NOT locked
                           01H=drive is locked; access is denied
          ──────────────────────────────────────────────────────────────────
    Info: Obtains the current setting of the disk access flag.  The driver
          may disable all disk access, for instance, when it detects
          unformatted media or an invalid boot record.

    Note: This function is not documented in official MS-DOS references.

See Also: Fn 44H (IOCTL)
          Fn 440dH (generic IOCTL for block devices)
          Fn 440dH 47H (set access flag)
          Generic IOCTL Data Packets
          DOS Functions
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