[syslinux] Boot off FAT based ISO image?

[Sam Liddicott]

  Is there a mix of SYSLINUX and ISOLINUX that can boot an ISO image 
from a FAT file system? Sort of like MEMDISK but doesn't need to load 
the entire great-big ISO into RAM or install an int-13 driver?

SYSLINUX would need to be installed on the FAT file system but it would 
want to chain-load ISOLINUX as installed on the ISO. ISOLINUX would load 
it's blocks from the ISO file in the FAT file system on the FAT devices 
instead of from a CD device.

As well as passing that knowledge to ISOLINUX it would be good if it 
could also pass some APPEND text used by ISOLINUX

Maybe the syslinux config would be:

KERNEL ubuntu-10.10.iso
APPEND cd_loopback=ubuntu-10.10.iso

syslinux notes that the kernel is an ISO file and so loads ISOLINUX from 
the ISO file. ISOLINUX adds: cd_loopback=ubuntu-10.10.iso to all APPEND 
strings

Thus, with a little bit of init-rd support to look for cd_loopback and 
find the ISO file; any newer linux ISO could be booted merely by 
dropping it onto a prepared memory stick.

or...
perhaps a MEMDISK option that didn't need to load the entire ISO because 
int 13 is only needed until the legacy ISOLINUX exec's the kernel it 
just loaded (via a hooked int 13)

Sam
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[FSF Associate Member #2325] 
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