Re: is my drive defect - request for comments

[Bill Davidsen <davidsen@tmr.com>]

Helmut Jarausch wrote:
> On  1 Mar, Thomas Schmitt wrote:
>   
> > Hi,
> >
> > Joerg Schilling wrote:
> >     
> .....
>   
> > > people in most cases solve their problems by writing in RAW mode
> > > or by killing hald.
> > >       
> > If raw mode prevents hald from disturbing a
> > burn run then this is an undocumented feature.
> >     
>
> Just one more comment (Attn: I don't know anything
> about the techniques of recording on a CD/DVD)
>
> As Joerg suggested in private mail, I tried
> using cdrecord after I had stopped hald.
> So on my system even without hald running
> cdrecord refused to write even the first sector.
> Switching to -raw96r mode (on a CD) did succeed
> but readcd -c2scan failed.
> Joerg said that my drive (LG GH22NS30 SATA)
> does not support c2 scanning. But then I wonder
> why it didn't get errors for all sectors (just many).
>
> I tried PLATINUM and VERBATIM media.
> This seems to be connected to this burner (and its
> predecessor LG GH20NS15)
>
> I have two PC (both AMD 64 running a recent Linux
> system with an 2.6.26 or 2.6.28 kernel)
> Both show this problem (with cdrecord only).
>
> I don't think it has to do with this recent Linux kernels
> since on two 32bit machines, running 2.6.26/8, as well, I have no
> problems though with an older (LG) burner.
>
> I managed to burn the CD with cdrskin, I mounted
> that CD and compared to the source directory.
> And the data was OK.
> I tried to "verify" that same CD with readcd (c2scan)
> and it failed with many sectors.
>
> cdrecord even failed to burn a DVD on those machines,
> while growisofs succeeded.
>
> NOTE, this is just the short history, no rating !
>
> Thomas suggested to use CDCK which validated
> both the CD and the DVD. But unfortunately
> that checks timings only and therefore is only an
> indirect measure of quality.
>
> I wished there a were a tool which could show
> "near failures" on a CD and on a DVD,
> since I use my burner for backup purposes only.
> And I want to be able to access my data even several
> years in the future (e.g. digital photographs)
>
>   
I've said this before, but it bears repeating: Get dvdisaster so you can 
add a layer of software ECC to your media. You have the choice of 
creating a "small" ISO image of 70-80% of the media capacity and then 
adding recovery information to the endof the image before you burn, or 
having the ECC information in another image and using the full size of 
the media for backup. A minimum of 20% redundancy is quite good, for 
critical stuff 30% is better. Burn a DVD with dvdisaster info, take 
something sharp and scratch the media. After verifying that you can't 
reas everything, recover the initial (data) with dvdisaster. Nothing is 
perfect, this is seriously improved correction.

> Thanks for all your help and I explicitly include
> Joerg here, as well.
> I have been using cdrtools for many years now and it
> had worked and is working flawlessly except on this new hardware.
>
> Helmut.
>
>   


--
Bill Davidsen <davidsen@tmr.com>
 "Woe unto the statesman who makes war without a reason that will still
 be valid when the war is over..." Otto von Bismark