[Fedora-livecd-list] Allowing livecd images large than 4GiB

[Bryan J Smith]

On Tue, 2008-12-16 at 11:33 -0600, Bruno Wolff III wrote:
> I tested it on a dual athlon system. The last motherboard update was something
> on the order of 5 years ago. So I would expect things to work on a wide
> range of systems.

Well, then I'd say you tested it.  You're sure the filesystem is UDF
Plain, correct?  It wasn't ISO 9660 Yellow Book (possibly as a result of
UDF not being accepted as an option for some reason)?

> My reading of the documentation was that the iso image looks like iso9660
> except the file size for the isoimage is reduced and hence is inconsistent
> with the udf information.

I've actually never dissected the ISO files I regularly create with
mkisofs.  But I know I've gone beyond 4.0GiB (~4.3GB) before, so they
must be Level 3.

We're kinda spoiled on Linux, because an .iso file != as written, but
the kernel hides a lot of that in the block access.  An .iso file, last
time I checked, is ISO 9660 "Yellow Book" (data) track.  So I'm curious
if an .iso file, as well as written to optical media, is still a single
track for > 4.0GiB (> ~4.3GB), or multiple Yellow Book tracks with the
extent in the first. 

> The documentation said that to access the file
> you would need to mount it with the udf or ufs drivers. My expectation
> is the bios never gets that far as it only needs to see the boot information.

Depends.  I was under the impression that when not using PC BIOS floppy
emulation, but native mode with El Torito, it uses still requires and
accesses the ISO 9660 Yellow Track, which needs to have filenames
limited to 31 characters.

But I might be confusing ISOLinux specifics.

> Once things are booting and linux is running I wouldn't expect problems.

Agreed there.


-- 
Bryan J Smith - Senior Consultant - Red Hat GPS SE US
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