[syslinux] missing syslinux details/docs

H. Peter Anvin hpa at zytor.com
Mon Nov 14 13:58:36 PST 2011

On 11/13/2011 06:27 AM, Bernd Blaauw wrote:
> I'm running into some issues with regard to isolinux and memdisk, and am
> not sure where to ask/look in the best way possible. These are
> DOS-related issues.
> So here goes:
> * Can MEMDISK map a imagefile (compressed? harddisk?) to more than
> (and/or beyond) 4GB of memory? Say you'd have 8/16GBGB and want 4GB
> available to the user so might as well use the other 4/12GB for MEMDISK.
> Or max 4GB due to 32bit memory/disk limitations in the module (or
> processor) ?

MEMDISK doesn't support it; it would have to go into PAE mode and set up 
page tables to be able to do it.  It's possible, but not supported at 
this time and it is unlikely to be a priority.

> * Is there a way to detect a system was booted (in non-emulation mode)
> through ELTORITO spec? MDISKCHK can detect the used loader(s), provided
> an instance of MEMDISK is found. Booting a CD, then chaining to
> floppy/HD from isolinux.cfg means not loading MEMDISK though.
> Basicly, I'd like to detect if ELTORITO.SYS should be loaded instead of
> awaiting its loading succes/failure.

Yes, there is an INT 13h call specified in the El Torito spec that you 
could use.

> * How would one create the tiniest uncompressed ISO possible? It seems
> like MKISOFS does some padding up to 600KB or so at minimum. My
> objective is a tiny ISO placed on diskette to test ELTORITO stuff:
> fd0 -> syslinux -> memdisk -> tiny.iso -> isolinux -> chain.c32 fd0 ->
> devload eltorito.sys /D:MEMCD

Not sure, however, if you want to stuff it on a diskette why not 
compress it?


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