Re: No 2 gig limit for /cdrom/KNOPPIX/KNOPPIX in Knoppix 5.0.1?
On Thu, May 25, 2006 at 06:36:18PM +0300, tapani.raikkonen@surfeu.fi wrote:
> Hi Klaus!
>
> > CAUTION: The "2 Gig limit" is NOT a cloop or linuxrc limit! cloop
> > supports 64 bit pointers, and therefore VERY large files (in todays
> > dimensions). The limit is within the root iso9660 filesystem: iso9660
> > only supports FILES smaller than 2GB. Really. Even that you CAN create
> > an iso9660 image with mkisofs that contains files larger than 2GB, the
> > filesystem itself will kind of "wrap around" at 2GB, and read invalid
> > data from every file above the limit.
>
> Thank you for you information.
>
> K3b uses growisofs over 2 gig because mkisofs can't handle so large files
> and can exceed 2 gig limit safely. Am I right?
Wrong. We are NOT talking about the size of an iso9660 filesystem, i.e.
both, mkisofs and growisofs, can very well produce .iso images that are
larger than 2GB (if the file system you want to use for storing the
image supports it, with is another issue).
But iso9660 has a limit for the SIZE OF AN INDIVIDUAL FILE WITHIN the
file system.
> > At first glance, you won't notice, because the "table of contents" is in
> > the first blocks of the file system. But every time you access files (or
> > blocks) above the 2GB limit of the KNOPPIX/KNOPPIX file, the iso
> > filesystem will return just WRONG data to you.
>
> Hope you are wrong ;)
Me, too. But see here:
http://www.ussg.iu.edu/hypermail/linux/kernel/0402.0/0495.html
> > I noticed this problem first on the 4.0 DVD image. Everything works
> > fine, unless you try to list the packages with dpkg -l, then dpkg
> > reports that it cannot read the dpkg database (which is, you guessed it,
> > because it's above the 2GB limit).
>
> No problem with 'dpkg -l' here. Everything is listed right.
Then, this file is still below the limit. Keep searching. ;-)
> > Now, you could circumvent this by not using iso as your base file system
> > where those compressed images are stored (for example, by using udf).
> > But this makes the DVD incompatible with older operating systems. An
> > ext2 file system just won't boot because you cannot place a el torito
> > boot record on it.
>
> Time to forget ext2 and use ext3 or reiserfs?
On CDs or DVDs, yes. They won't boot.
> There is, of course, old
> computers that don't even accept isolinux (only syslinux) but usually they
> don't even have DVD drive. So I have forget myself old computers.
Sorry, you lost me here.
> But real
> Knoppix (not a remastered one) is something more and needs to be more
> compatible with older machines, too. I see.
Yes, Knoppix is supposed to boot on old computers, too.
Regards
-Klaus Knopper
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