[syslinux] Looking for testers and advise about ISOLINUX within ISO 9660

[Thomas Schmitt]

Hi,

Helmut Hullen wrote:
> Hallo, Thomas,
> ...
me, previously:
> > I understand from the code of util/isohybrid
> > that the ISOLINUX user is supposed to produce a
> > specially enabled isolinux.bin as first step.
Helmut:
> Have I to make this file "isolinux.bin" manually?

Seems i misunderstood it a bit.
So i am possibly not the right person to ask. :))

In syslinux-3.72/doc/isolinux.txt i read:
"
 Starting in version 3.72, ISOLINUX supports a "hybrid mode" which can
 be booted from either CD-ROM or from a device which BIOS considers a
 hard disk or ZIP disk, e.g. a USB key or similar.
 To enable this mode, the .iso image should be postprocessed with the
 "isohybrid" script from the utils directory:
"

So obviously ISOLINUX is enabled for isohybrid
by default in the new ISOLINUX version.
H. Peter Anvin seems not to object if one applies
the manipulations of utils/isohybrid by default.


> I produce the *.iso file with "mkisofs" from the slackware package  
> "cdrtools-2.01.01a36" (or newer).

It should work with ISO images from mkisofs or genisoimage
or xorriso-0.2.7 if only isolinux.bin is ready for it.

The reason for the manipulation run is the fact that
none of the current ISO 9660 generators writes a
Master Boot Record at the start of its output but
rather an El Torito CD boot record 17 blocks later.

utils/isohybrid extracts info from disk filesystem
and El Torito record. It then writes a Master Boot
Record to the start of the image. It only works
if the image resides as data file in a read-write
filesystem.

This does not cripple the ISO 9660 image because
the content of the first 32 kB of such an image has
no particular meaning in the specs.
ECMA-119, 6.2.1 :
"
  The System Area shall occupy the Logical Sectors
  with Logical Sector Numbers 0 to 15. The System Area
  shall be reserved for system use. Its content is not
  specified by this Standard.
"
A clear invitation to do interesting things in there.


Have a nice day :)

Thomas