AGM attendees from Cork; Re: [ILUG] Backing up a CD

[Martin Feeney]

On 13 Jun 00, at 13:01, Rik Dunphy wrote:

> It should be possible to read raw binary data. Red/Yellow book is what you
> called it, a format. It should be (and as far as I know is) possible to
> read the raw data from the disk to create a binary image of the disk, by
> circumventing the formats. 

Have you tried cdrdao with the following:

cdrdao copy --source-device x,x,x --device y,y,y --buffers 64

It should be fine with kernel versions >2.2.6.  If you have a kernel version less 
than this you'll need to get the sg-buffer patch (available here: 
ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/alpha/).  Definitely do not use --on-the-
fly as it'll probably buffer underrun on you.

I've used cdrdao this way myself and it works for mixed mode (on a fairly ancient 
CD/RW (HP7200i).

The latest version of cdrdao (1.1.3) supports reading of CD-TEXT and has a new 
command read-cd which reads all tracks including gap information into a single 
.bin file.

How CD-TEXT works:

There are 8 sub-channels stored on a CD alongside (in fact interleaved with) the 
normal data (whether it be audio or data).  These are named P-W.  The P subchannel 
contains data about the start and end of tracks, the Q subchannel contains nifty 
extra information for audio like index marks and the copy-protection bit so DATs 
will record silence instead of the track.  The R-W are effectively unused in 
standard audio or data CDs.

CD-G and CD-TEXT both use the R-W subchannels, but differently.  For CD-TEXT the R-
W subchannels are used in the leadin section as text for the entire disc.  The R-W 
subchannels in the audio sectors of the disc contain the text for the individual 
track (multiple times to speed up access times).

Now there are scsi commands to read and write to the subchannels, but if the CD 
drive doesn't support it, then it shouldn't work.  I have no idea how NTI CD Maker 
pro is writing these subcodes if the recorder says it doesn't allow it.

I would encourage you to get the latest cdrdao and try again (but use a CD/RW for 
your testing as it'll probably take a few attempts to get it to work if it'll work 
at all).  Try setting the device manually to generic-mmc or generic-mmc-raw or 
possibly use the plextor driver.  You might have to muck about with the --read-raw 
switch as well.  I've never needed to copy a CD-EXTRA so I'm not sure what 
settings will work for them.

Martin.