INT 21 - DOS 5.0 - IOCTL - QUERY GENERIC IOCTL CAPABILITY (DRIVE)
AX = 4411h
BL = drive number
CH = category code (see AX=440Dh)
CL = function code
Return: CF clear if successful
AX = 0000h  specified IOCTL function is supported
CF set on error
AL = 01h    IOCTL capability not available
Note:   a program which wishes to use Generic IOCTL calls beyond those in the
standard DOS 3.2 set may use this call first to see whether a
particular call is supported
SeeAlso: AX=440Dh,AX=4410h

See also: 21440C

214411 - DOS 5.0 - IOCTL - QUERY GENERIC IOCTL CAPABILITY (DRIVE)