Compatibility: 2.0+

Expects: AX    4405H

BL    drive number (0=default, 1=A, 2=B, etc.)

CX    byte count (amount of data to send)

DS:DX Address of buffer containing data to send

Returns: AX    error code  if CF is set to CY

Number of bytes actually sent (if no error)

Info: Some block device drivers support this method of communicating

with a device driver to select special features.  The layout and

contents of the control 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.

See Also: Fn 44H (IOCTL)

Fn 4403H (Send Control Data to Character Device)

Fn 4404H (Receive Control Data from Block Device)

DOS Functions

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