[syslinux] ISOLINUX: why -boot-load-size 4?

[H. Peter Anvin]

Mario 'BitKoenig' Holbe wrote:
> Hello,
> 
> i'm just curious, why the -boot-load-size 4 for mkisofs
> with isolinux.bin is needed. I searched the list archive
> and found nothing and found nothing anywhere else.
> 
> Since the isolinux.bin is much bigger than 4 * 512 byte,
> I'd suspect, it wont get completely loaded.
> 
> With -boot-load-size 4, mkisofs reports:
> Size of boot image is 4 sectors -> No emulation
> Without it, mkisofs reports:
> Size of boot image is 20 sectors -> No emulation
> 
> I know (because I tested it), that everything works fine
> with -boot-load-size 4, but my simple question is:
> Can I leave it away or does that kill something?
> And what exactly is the difference.
> 

The reason is simply that not all BIOSes will handle any other size than 
  4.  The quality of some El Torito BIOSes is absolutely atrocious.

	-hpa