DOS Fn 440fH: IOCTL Set Logical Drive Map
Expects: AX 440eH
BL drive in question (0=default, 1=A, 2=B, etc.)
Returns: AX error code if CF is set to CY
AL 00H: the drive has only one drive number (if no error)
else: drive number currently being used to refer to this
Info: This tells the device driver that its "drive alias" will be used
in subsequent read/write access.
Notes: ■ The phantom floppy concept is used by DOS on systems which have
a single diskette drive. In that case, when you attempt to
access drive B, DOS prompts with:
Insert diskette for drive B.
Press any key when ready.
Programs may use this function to ell that driver that the
"disk for drive B" is already in place--and thus avoid having
DOS issue this prompt.
■ Phantom floppies are also created by the Driver.Sys installable
See Also: Fn 44H (IOCTL)
Fn 440eH (query logical drive map)