[Vox-Outreach] Need more CD burns!

[Mike Simons]

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On Mon, May 12, 2003 at 04:29:54PM -0700, Michael Wenk wrote:
> On Monday 12 May 2003 01:25 pm, Mike Simons wrote:
> > On Sun, May 11, 2003 at 12:13:07AM -0700, Michael Wenk wrote:
> > > Out the of the batch I sent in, I had 2 discs fail(which is around 4%=
.)
> >
> >   Wow... I didn't expect that many failures, I've not burned disks... in
> > the last 4 years.  I'm just surprised.
>=20
> I have no idea why I have such a high fail rate.  Previous to this escapa=
de,=20
> I've burned about 6 discs a year and had zero fails.  I burned some music=
=20
> back in february and got my first fail on this burner.  It also seems to =
be a=20
> function of blanks.

  I would suspect the disk blanks more than the burner...=20

- What brand/model of cd burner do you have?

> > > Bill wrote:
> > > > How long does it take to test?
> >
> >   I would prefer the disks be verified before the event...=20
> >
> >   I *really* don't want people to be donating to get a disk that can not
> > work because it's a coaster.  I did randomly test on of the none Mike W,
> > disks and found it to be a dud... couldn't even mount it as a ISO
> > filesystem.
>=20
> I'm unclear, did one of this discs I did come out a dud?  Its certainly=
=20
> possible I could have missed one, sigh. =20

  I haven't had a problem with any of the disks you made.

  I randomly tested one of the disks that you did not make... and it=20
didn't even come up to the Knoppix Lilo Boot Prompt.


> > > I _barely_ qualify it as testing, as I don't test
> >
> > - Have you considered doing a CD Verify step?
> >   (either in a cd-rom drive or
> >    on another machine that does not have the burner attached)
>
> Well, what I would probably do is use dd to readback the CD, and them md5=
sum=20
> them and compare.  I would also probably test boot as well just for kicks=
. =20
>
> > - Which cd burning program are you using to make the disks?
>=20
> cdrecord on praxis is slightly older, and has the oldest burner I own. =
=20
> My other system gondor has the latest and greatest gentoo cdrecord and a=
=20
> burner that I have not used much to burn discs.

  xcdroast has a verify option which does a block by block compare of=20
the cd to the image... but I see the program to do that is in the xcdroast
package and no option to verify that is built into cdrecord.

  I think a md5sum check of the disk would be a better test than a
sample boot of each disk.  It should complete much faster than a burn
if you can put the disk in a drive with 50x-ish burn speed.  The md5sum=20
might actually complete faster than a Knoppix Boot process, depending
on the machine you are using to boot them... ;)

Something like this may work...

first time like:
---
md5sum /dev/cdrom > knoppix.md5

rest of runs like:
---
md5sum -c knoppix.md5

--=20
GPG key: http://simons-clan.com/~msimons/gpg/msimons.asc
Fingerprint: 524D A726 77CB 62C9 4D56  8109 E10C 249F B7FA ACBE

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