[syslinux] How to unload memdisk within DOS?

[H. Peter Anvin]

Bernd.von.Osten at bccomponents.com wrote:
> 
> BWLOADHI has a "bwloadhi /u" option, which uses an additional int13h
> function to trigger the unload procedure. Maybe this can be implemented in
> Memdisk as well?
> 

Something like that would work.

> At the moment I'm thinking about a quick and dirty test program (IMDL -
> IsMemDiskLoaded), which detects the presense on Memdisk in the workstations
> memory but looking for magic strings in Memory
> (like:
> "MEMDISK " VERSION " " DATE;
> const char copyright[] =
> "Copyright " FIRSTYEAR "-" COPYYEAR " H. Peter Anvin";
>  )

Unfortunately doesn't work -- that's in the setup code, which is not 
retained.

> Then I can react on that issue correctly in my batch file within dos and
> ignore the presence test of the bootmedia in the boot drive.

The easiest thing to do, if this is possible, is to put a well-known 
volume label on the MEMDISK image and look for that.  I don't know if 
that's what you want to do, though.

	-hpa