Document image growing/modify problems.

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Vreixo Formoso 2008-02-09 16:54:04 +01:00
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@ -46,6 +46,50 @@ Requirements:
- libburn 0.4.2 headers must be installed at compile time. It is not required
at runtime.
Know bugs:
Multisession and image growing can lead to undesired results in several cases:
a) Images with unsupported features, such as:
- UDF.
- HSF/HFS+ or other Mac extensions.
- El-Torito with multiple entries.
- ECMA-119 with extended attributes, multiple extends per file.
- Non El-Torito boot info.
- zisofs compressed images.
- ...
In all these cases, the resulting new image (or new session) could lack some
features of the original image.
In some cases libisofs will issue warning messages, or even refuse to grow
or modify the image. Others remain undetected. Images created with libisofs
do not have this problems.
b) Bootable El-Torito images may have several problems, that result in a new
image that is not bootable, or that boots from an outdated session. In many
cases it is recommended to add boot info again in the new session.
- isolinux images won't be bootable after a modify. This is because
isolinux images need to have hardcoded the root dir lba. libisofs cannot
know whether an image is an isolinux image or not, so the user is
responsible to tell libisofs that it must patch the image, with the
el_torito_patch_isolinux_image() function. This problem could also exists
on other boot images.
- Most boot images are highly dependent of the image contents, so if the
user moves or removes some files on image it is possible they won't boot
- There is no safer way to modify hidden boot images, as the size of the
boot image can't be figured out.
c) Generated images could have different ECMA-119 low level names, due to
different way to mangle names, to new files added that force old files to
be renamed, to different relaxed contraints... This only affect the
ISO-9660 info, not the RR names, so it shouldn't be a problem in most
cases. If your app. relies on low level ISO-9660 names, you will need to
ensure all node names are valid ISO names (maybe together with some
relaxed contraints), otherwise libisofs might arbitrarily change the names.