FC3 can no longer successfully burn CDs]

Peter Jones pjones at redhat.com
Wed Jan 19 16:46:56 UTC 2005


On Wed, 2005-01-19 at 11:43 -0500, Peter Jones wrote:
> On Sun, 2005-01-16 at 11:54 -0500, Alan Cox wrote:
> > On Sun, Jan 16, 2005 at 11:51:13AM -0500, Fulko Hew wrote:
> > > >Thats correct behaviour. The end of a CD is very low accuracy only.
> > > 
> > > OK.  But (in my nievity) doesn't that make it difficult to 'dup' CDs?
> > > ie. you couldn't do a:   dd if=/dev/cdrom of=test.iso bs=2048
> > 
> > Each copy will gradually get a bit longer unless you know the real .iso size
> > (which is easy to find).
> 
> FWIW, we ship the program "isosize" to do this.  So use -pad with
> cdrecord while burning, and then you can do this to make an iso from it:
> 
> dd if=/dev/cdrom of=test.iso bs=4096 \
> count=$(($(isosize /dev/cdrom)/ 4096+1))
> 
> And that shouldn't have the growth problem Alan has mentioned.  Note
> that the "+1" is only really needed if the image doesn't end on a block
> boundary.

Of course, also note that I'm completely on crack about the block size,
and you should just do:

dd if=/dev/cdrom of=test.iso bs=2048 count=$(($(isosize /dev/cdrom)/2048))

as 2048 is the block size on a CD device.

Dunno what I was thinking.
-- 
        Peter




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