Compatibility: 2.0+
Expects: AX    4404H
BL    drive number (0=default, 1=A, 2=B, etc.)
CX    buffer size (maximum number of bytes to receive)
DS:DX Address of buffer to receive data
                                                                  
Returns: AX    error code  if CF is set to CY
Number of bytes actually received (if no error)
                                                                  
Info: Some block device drivers support this method of providing
device-specific information to programs; for instance, it is used
to tell DoubleSpace to flush its cache.  The layout and contents
of the returned data varies from device to device.

Notes:   This fn is supported only if bit 14 of the Device Attribute
(the rDevAttr field of the driver's DevHdrRec structure) is
set.  Use Fn 4400H to check this bit.

  DoubleSpace API supports IOCTL strings for some fns.

See Also: Fn 44H (IOCTL)
Fn 4402H (Receive Control Data from Character Device)
Fn 4405H (Send Control Data to Block Device)
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DOS Fn 4404H: IOCTL Receive Control Data from Block Device