'ddrescue' and detailed into on filesystem internals.
SomeDeveloper
I need to make backups of what I suspect are copy-protected CDs. What
I'm hearing on the Net is that GNU ddrescue is what I need to try. I
tried it on one (copy-protected) CDR and then used wodim to burn a new
CD with ddrescue image. But what is happening now is that I'm able to
run the software only in the following two ways:
1. from the ripped ddrescue image mounted on my filesystem (loop
mode), or
2. from my wodim burnt CD on the physical box originally used to rip
the image in the first place!
Meaning, if I use the CD copy from a different machine (a Windows
machine), the (autorunnable) software on the CD does not run!
I first suspected that may be I didn't specify the right set of
options (out of the gazillions available) when invoking wodim. But,
even if I use Nero to burn the ddrescue-d image , the problem remains.
This tells me, something's wrong in the ddrescue-d image itself.
Could someone be kind enough to point me in the right direction? I'm
very surprised by all of this 'cos I thought (and still think for that
matter) that regardless of the copy protection mechanism used on the
media (CD/harddisk/floppy), even a low-level system tool such as GNU
ddrescue (that can copy bad sectors, etc) is being rendered useless/
ineffetive by the copy-protection scheme!
Also, I'm very much eager -- now -- to learn about the internal
details of CD and hard disk devices and file systems, especially in
the Linux/Fedora context? For example, can I create a custom/adhoc
file system on a blank media to prevent ripping of my own software by
others? If so, how? If no, why not?
I'd greatly appreciate a detailed response, or book recommendations,
or any good www links that treat this subject matter in great and full
detail.
Thanks much in advance,
/SD
SomeDeveloper
Fixed the typo in the subject ('into' --> 'info').
Sorry,
/SD
Dances With Crows
> I need to make backups of what I suspect are copy-protected CDs. What
> I'm hearing on the Net is that GNU ddrescue is what I need to try.
Really? Where did you hear that? I would suggest doing "cdrdao copy"
instead. dd and ddrescue will only get the first session of a
multisession CD, they only work on data tracks, and they don't bypass
most copy-prevention bullshit by reading data from the original CD at
the lowest level possible. cdrdao reads the 2352-byte raw sector, dd
reads the 2048-byte error-corrected sector, you know?
> I first suspected that may be I didn't specify the right set of
> options (out of the gazillions available) when invoking wodim.
Joerg has said wodim is buggy. He might be right. But you're using the
wrong ripping tool, and that's probably what's causing the problems you
reported.
> Also, I'm very much eager -- now -- to learn about the internal
> details of CD and hard disk devices and file systems
It's not nearly as interesting as you might think. ISO9660 is simpler
than most filesystems, but still semi-complex. Take a look at the
mkisofs source and /usr/src/linux/fs/isofs/ for some more info. HTH,
--
"Oh bother," said the Borg, "We've assimilated Pooh."
--MHR on alt.fan.pratchett
My blog: http://crow202.org/wordpress/
Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
SomeDeveloper
wrote:
> SomeDeveloper staggered into the Black Sun and said:
>
> > I need to make backups of what I suspect are copy-protected CDs. What
> > I'm hearing on the Net is that GNU ddrescue is what I need to try.
>
> Really? Where did you hear that?
Probably I misread/misunderstood, and here's how I think:
Since dd was failing midway due to errors and ddrescue seemed to be
capable of copying 'everything' (including bad/damaged sectors) (and
hence I believe the 'rescue' in its name), I thought it would be able
to handle copy-protected CDs as well... because I thought copy-
protection was perhaps being achieved via some non-standard sector
tweaking... which would be functionally equivalent to 'bad sectors'
from the point of view of standard/regular CD copying tools.
Again, I'm a total newbie in this area of CD backups, CD/HDD/FDisk
file systems, file-formats, dd, ddrescue, wodim, cdrdao, K3b... While
I have learned quite a bit on what will not work in these past 2 days,
I still don't know what will, how, and last but not the least: why :-
(
I'm still hopeful that you and / or other hackers on this forum have
been here before and know what the solution / workaround is.
> I would suggest doing "cdrdao copy"
> instead. dd and ddrescue will only get the first session of a
> multisession CD, they only work on data tracks, and they don't bypass
> most copy-prevention bullshit by reading data from the original CD at
> the lowest level possible. cdrdao reads the 2352-byte raw sector, dd
> reads the 2048-byte error-corrected sector, you know?
I tried issuing 'cdrdao copy --device /dev/sr0' command.
Took over 2 hours and I was hoping the wait would be worth it, but
nope, this didn't work either. Got a whole bunch of errors. Following
is a snippet of the console log:
// Console log begins.
<snip>
Found L-EC error at sector 6821 - ignored.
<snip - Hundred or so such erros here>
Found L-EC error at sector 10967 - ignored.
Please insert a recordable medium and hit enter.
WARNING: No super user permission to setup real time scheduling.
Turning BURN-Proof on
Enabling JustLink.
ERROR: Cannot set Ricoh mode page 30.
Executing power calibration...
Power calibration successful.
Writing track 01 (mode MODE1_RAW/MODE1_RAW )...
Wrote 752 of 752 MB (Buffers 100% 97%).
Wrote 335411 blocks. Buffer fill min 90%/max 100%.
Flushing cache...
Writing finished successfully.
CD copying finished successfully.
// Console log ends.
The intermediate image file size this time was bigger though...
-rw-r----- 1 ppp ppp 788886672 2008-08-27 17:44 cddata18221.bin
-rw-r----- 1 ppp ppp 686921728 2008-08-27 00:20 ddrescued-image.iso
which tells me that cdrdao was certainly able to salvage more stuff
relative to ddrescue!
> > I first suspected that may be I didn't specify the right set of
> > options (out of the gazillions available) when invoking wodim.
>
> Joerg has said wodim is buggy. He might be right. But you're using the
> wrong ripping tool, and that's probably what's causing the problems you
> reported.
Thanks for the info on wodim.
> > Also, I'm very much eager -- now -- to learn about the internal
> > details of CD and hard disk devices and file systems
>
> It's not nearly as interesting as you might think. ISO9660 is simpler
> than most filesystems, but still semi-complex. Take a look at the
> mkisofs source and /usr/src/linux/fs/isofs/ for some more info. HTH,
I personally find it hard to figure out the spec/documentation from
someone else's code. But will definitely try what you suggest, thanks!
So, are there, then, no decent books/docs/links that describe all
these blessed concepts of normal CDs, copy-protected CDs, various file-
system structures?