Cookie ID: 'XHDI'. The contents of the cookie points to the start address of a function which provides procedures for dealing with block storage devices. As an additional check, the function is preceded by the LONG constant 0x27011992.
The contents of the XHDI cookie may change (because it can be used by more than one driver). Therefore, in some applications (example: Desk accessories) the cookie contents must be inquired each time before the handler is called.
How to install more than one XHDI driver:
|(1)|| During the installation, check whether the cookie is already
set. If so:
|(2)|| For XHGetVersion first jump through the old vector and return
the minimum of this and your own version number.
|(3)|| For XHDrvMap first jump through the old vector and then OR in
the drive bits for the devices supported by you.
|(4)|| For all other functions: Check whether it is one of your
devices. If not, jump through the old vector.
See also: XHDI specification About the GEMDOS About the BIOS Cookie jar SCSI specification