INT 21 - DOS 2+ - IOCTL - WRITE TO BLOCK DEVICE CONTROL CHANNEL
AX = 4405h
BL = drive number (00h = default, 01h = A:, etc)
CX = number of bytes to write
DS:DX -> data to write
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note:   format of data is driver-specific
SeeAlso: AX=4404h,INT 2F/AX=122Bh

See also: 214403

214405 - DOS 2+ - IOCTL - WRITE TO BLOCK DEVICE CONTROL CHANNEL