no it's an iso issue - because it can be fixed in the iso, and a _lot_,
_lot_ of different brand burners have this problem (like hundreds of
different models from different manufacturers) - it's classic case where
fixing it in software is worth it... especially DVD burners have this
problem as many can't record 2KB sectors and can only do 32KB...
On Fri, 4 Mar 2005, William Warren wrote:
> this seems to be a burner issue with that liteon. With my NEC i
> burned them straight from the isos without issue. Even using an
> old cranky hp 10x burner i did not have any problems with he
> isos. This i think falls under a hardware issue not a .iso issue.
>
> Maciej ?enczykowski wrote:
> > I just burned 3 CD's (at speed 16 on a 40x capable burner) of "CentOS4
> > i386-bin CD1" (md5sum of image on HDD is OK, after padding it changes but
> > who cares)
> > One straight from iso, the other with appended 300KB zeroes, the third
> > with cdrecord -pad.
> >
> > CD A: iso
> > CD B: iso with builtin 300KB pad (150 sectors of 2KB, IMHO 15 is enough)
> > CD C: iso with cdrecord -pad (15 zeroed sectors of 2KB = 30KB)
> >
> > cmp -l /dev/cdrom file.iso-unpadded
> > CD A: IO error (within the last 30KB)
> > CD B: EOF on file.iso
> > CD C: EOF on file.iso
> >
> > cmp -l /dev/cdrom file.iso-prepadded
> > CD B: OK
> > [wonder why I'd expect an
> > IO error (within the last 30KB of the padded image)]
> >
> > running md5sum on CD A/B gives IO ERRORS, while C works (think this was
> > just a matter of luck).
> >
> > My theoretical explanation which isn't perfect:
> > Why? Cause the burner can only burn in 32KB blocks (16 sectors) and
> > anything leftover doesn't burn (is left of the disk, so it can't be read)
> > (my drive: [LITE-ON ][DVDRW SOHW-832S ][VS0A])
> >
> > CD A: Mediacheck FAIL
> > CD B: Mediacheck OK
> > CD C: Mediacheck OK
> >
> > This proves pre-padding CD iso images before distribution with a few (30KB
> > at least, 300KB suggested) KB worth of zeroes fixes burn issues and
> > retains a working mediacheck - even if the last part of the burned image
> > is unreadable (since it'll be in the unimportant padding...)
> >
> > Thus images should be padded after implanting the md5sum and before
> > calculating the md5sum for distribution.
> >
> > ie.
> > mkisofs > file.iso
> > impland-md5iso file.iso
> > dd if=/dev/zero bs=2048 count=150 >> file.iso
> > md5sum file.iso > MD5SUMS
> > upload file.iso MD5SUMS
> >
> > Cheers,
> > MaZe.
> >
> > On Thu, 3 Mar 2005, Maciej ?enczykowski wrote:
> >
> >
> >>I'm pretty sure we should just prepad the ISO's with 300KB worth of zeroes
> >>before calcing their md5sums and distributing them, I'll check whether
> >>this works (what's a CD worth? 30cents?) in a moment and report back.
> >>If this only passes mediacheck (all reports are it should) then this will
> >>eliminate _all_ non-badburner and bad-media related burn errors (some 95%
> >>I'd say) and save a lot of trouble for a lot of people (ie I wasted a CD
> >>and 10 minutes burning the 4 centos4 cd's).
> >>
> >>Cheers,
> >>MaZe.
> >>
> >>On Thu, 3 Mar 2005, Collins Richey wrote:
> >>
> >>
> >>>On Thu, 3 Mar 2005 14:27:02 -0500, Lamar Owen <lowen@xxxxxxxx> wrote:
> >>>
> >>>
> >>>>This is my last post on the subject since people seem to be more interested in
> >>>>splitting hairs than in helping people get a good burn on their hardware.
> >>>>And whether their hardware is broken or not is irrelevant; there is a
> >>>>recommendation that works for the vast majority of people that have the
> >>>>problem, and I simply looked through my archives to try to help people get a
> >>>>good burn. If I had known that people were going to nitpick my post I
> >>>>would not have bothered looking through my archives, nor would I have
> >>>>posted it.
> >>>>--
> >>>
> >>>Please don't consider my questions on the subject "nitpicking." I'm
> >>>just enterested in learning "the rest of the story," most especially
> >>>since it runs counter to several years of my own experience.
> >>>
> >>>Thank you for replying at length. Helping people to understand "why"
> >>>is somethimes just as important as understanding "how" or "what."
> >>>
> >>>
> >>
> >>_______________________________________________
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> >>CentOS@xxxxxxxxxxx
> >>http://lists.caosity.org/mailman/listinfo/centos
> >>
> >
> > _______________________________________________
> > CentOS mailing list
> > CentOS@xxxxxxxxxxx
> > http://lists.caosity.org/mailman/listinfo/centos
> >
>
>
