INT 18 - DISKLESS BOOT HOOK (START CASSETTE BASIC)
Desc: called when there is no bootable disk available to the system
Notes: very few PCs other than those produced by IBM contain BASIC in ROM, so
the action is unpredictable on compatibles; this interrupt often
reboots the system, and often has no effect at all
some PC and XT clones had an optional IBM CASSETTE BASIC stored
in the ROM, too.
most BIOSes will display an error message similar to "NO BASIC", and
either reboot or return to the caller.
PS/2 machines usually pop up a graphical box to the effect that
the user should enter a floppy and press F1.
Some clones display the message "No boot device available,
strike F1 to retry, F2 for setup utility"
network cards with their own BIOS can hook this interrupt to allow
a diskless boot off the network (even when a hard disk is present
if none of the partitions is marked as the boot partition)
SeeAlso: INT 2F/AX=4A06h,INT 86"NetBIOS",INT 2F/AX=4A06h,INT 2F/AX=4A07h