[Vox-Outreach] Need more CD burns!

[Michael Wenk]

On Monday 12 May 2003 01:25 pm, Mike Simons wrote:
> On Sun, May 11, 2003 at 12:13:07AM -0700, Michael Wenk wrote:
> > On Saturday 10 May 2003 11:30 pm, Bill Kendrick wrote:
> > > Out of curiosity, what seems to be the failure rate?
> > > (That is, how many discs seem to come out bad?)
> >
> > Out the of the batch I sent in, I had 2 discs fail(which is around 4%.)
> > Lately it seems higher, but that was because I was burning them on a
> > system with a faster CD burner, but slowing the burn speed back down
> > seems to have corrected that problem.  I figure it have around 4% failure
> > rate or so when its all over.
>
>   Wow... I didn't expect that many failures, I've not burned disks... in
> the last 4 years.  I'm just surprised.

I have no idea why I have such a high fail rate.  Previous to this escapade, 
I've burned about 6 discs a year and had zero fails.  I burned some music 
back in february and got my first fail on this burner.  It also seems to be a 
function of blanks.  I got some Verbatim blanks a while back, and unless I 
burned at 2X burnrate, I would get a coaster more than I would get a workable 
CD.  
 
>
> > > How long does it take to test?  I'm not completely opposed to handing
> > > out a few discs that might not boot, if it means being able to have a
> > > LOT more discs on-hand.  If people have problems, they know how to get
> > > ahold of us.
>
>   I would prefer the disks be verified before the event... I feel
> terrible telling people about all the great things the disk can do to
> have to follow it up with ... "oops, we gave you a dud".  *especially*
> when people give us donations.
>
>   I had a few people give us donations at WEF after I gave them disks...
> it goes something like:
> ===
> them: Oh so these disks are free?!?
> me:   Yes they are free, but if you have any money and want to give us a
>       donation you can put it in that jar right there... <me points>
> them: okay, great.  <they pull out wallet and put in money>
> me:   Well if you are going to give a donation, let me trade you for one
>       of the better CDs, <me looks for one of Michael Wenk's burned CDs>...
> ===
>
>   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.

I'm unclear, did one of this discs I did come out a dud?  Its certainly 
possible I could have missed one, sigh.  


>
> > I _barely_ qualify it as testing, as I don't test
> > each of the apps, or anything like that... The reason it is a pain, is
> > because while I'm burning, normally I'm doing stuff on the XP system. 
> > But all in all, I think the testing is a good thing to do...
>
> - 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)
>
>   I would expect this is much more reliable because it does a complete
> disk read of all blocks... the disk image could have thousands of
> bad blocks and still boot.

Well, what I would probably do is use dd to readback the CD, and them md5sum 
them and compare.  I would also probably test boot as well just for kicks.  



>
> - Which cd burning program are you using to make the disks?

cdrecord on praxis is slightly older, and has the oldest burner I own.  
My other system gondor has the latest and greatest gentoo cdrecord and a 
burner that I have not used much to burn discs.  It was bought around 2-3 
years ago, and is much faster than my other one.  However, I still stick with 
around an 8x burnspeed.  

Mike


-- 
wenk@praxis.homedns.org
Mike Wenk