Re: LinuxProMagazine Issue137 K7.0.0 testcd
On Wed, 11 Apr 2012 02:39:52 +0200
Klaus Knopper <debian-knoppix@knopper.net> wrote:
> Hello Charles,
>
> On Tue, Apr 10, 2012 at 07:40:48PM -0400, Charles Evans wrote:
> > On Tue, 10 Apr 2012 23:11:54 +0200
> > Klaus Knopper <debian-knoppix@knopper.net> wrote:
> > ...
> > > In this case, I believe the question was about the DVD included
> > > in the magazine, which might have had undergone some uncalculated
> > > modifications.
> > ...
> > > Regards
> > > -Klaus
> > >
> > > > On Tue, Apr 10, 2012 at 2:25 PM, Edwin Evenson
> > > > <[1]edwin.k.evenson@gmail.com> wrote:
> > > >
> > > > KNOPPIX/KNOPPIX failed sha1sum on 2 copies of this dvd.
> ^^^^^^^^copies like
> "copies", or originals from the magazine?
>
> > > > Anyone else have this problem?
> > > > TIA
> > > > Ed
> >
> > Yes, I got the Linux Pro magazine,
> > and sha1sum fails on the original DVD.
> > BTW extract_compressed_fs also fails, always on the same block.
> ^^^^^^^^^^^^^^^^^^^^^you tried this on the KNOPPIX/KNOPPIX
> file, right?
>
> > I even used readom to read the DVD at 2x (VERY long time)
> > to an .iso file, mount -l the .iso, this also fails sha1sum
> > & extract_compressed_fs, with exactly the same errors.
>
> This indicates that indeed your magazine DVD copy is broken. Can you
> check, after that error occurs, if "dmesg" shows "read errors" on
> /dev/sr0? Are there any visible "holes" or "blank/dirty spots" on the
> DVD surface? If one of these is the case, you can probably get a free
> replacement of the defective DVD(s) from Linux Magazine.
>
> Regards
> -Klaus
Thanks for the quick reply!
The DVD is very thin, half the usual thickness, and very flexible.
It looks generally cloudy.
Reading at full speed the drive speed winds up and down continually
(maybe drive detects a warp or ~?) but no read errors.
# unmounted DVD in sr1:
n=`isoinfo dev=/dev/sr1 -d | gr "Volume size is:" |
awk '{ print $NF ; }' ` && echo $n
# ^ get last field
time readom sectors=0-$n dev=/dev/sr1 retries=0 speed=60
meshpoints=500 f=/dev/null
# read at 6x. ^ ok, no errors, no retries. drive speed stays constant.
# Read speed report stays stable.
# dmesg shows only normal ISO 9660 lines.
# mounted DVD:
cfv -f KNOPPIX/sha1sums
KNOPPIX/KNOPPIX : crc does not match
(c873541e03834e9b9574089bf3461e8a8b0f4931!=a5d6cce5250c0a03ad6f501cd0d8b5eb09a48c5c)
# ^ note that background.png is OK.
extract_compressed_fs KNOPPIX /dev/null
extract_compressed_fs: compressed input has 73228 blocks of size 131072.
[Current block: 0, In: 39kB, Out: 128kB, ratio 322%, complete 0%]
[Current block: 7322, In: 260876kB, Out: 937344kB, ratio 359%,
complete 9%]
Uncomp: input corrupt 10978
# ^ this block always fails, original DVD, fast or slow,
# ^ or copied to thumb drive. no errors on dmesg.
Please, anyone with an original DVD, reply with your sha1's
cvevans
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