DOS Fn 4404H: IOCTL Receive Control Data from Block Device
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)