[syslinux] booting clonezilla *.iso via PXE fails

[H. Peter Anvin]

On 07/10/2010 11:43 AM, Miller, Shao wrote:
> Sorry for all the e-mail, folks.
>
> It just occurred to me that you might be encountering TFTP problems,
> Helmut!  Perhaps the .ISOs are only partially downloaded, resulting in
> fractional images in RAM!  Adding "pause" to the MEMDISK's APPEND
> directive should allow for MEMDISK to report the sizes of things,
> including the .ISO "initrd" that was passed to it by PXELINUX.
>
> - Shao Miller
>

That *shouldn't* happen... especially if using compressed memdisk images 
(one of the advantages to compressing your memdisk images is that the 
decompressor does CRC32 verification.)

Furthermore, the error messages he's getting are definitely coming from 
ISOLINUX, not from the loaded OS.  Specifically, it's reporting that it 
received AH=02h from EXTENDED READ.

Error 02h is ADDRESS MARK NOT FOUND, which MEMDISK returns on an attempt 
to read/write beyond the end of the disk.  Really old versions of 
MEMDISK (3.52 or earlier) also would return it for an impossible target 
address, which should never happen with ISOLINUX, but could be a 
reflection of the DAPA buffer being corrupt and containing garbage.

	-hpa