Mark Hounschell wrote:
If I take a CD, such as one of the SuSE CD's, and do to following:
dd if=/dev/cdrom of=isofile
Every thing completes with no errors. Howver if I create my own cd using the following:
mkisofs -V "MYLABEL" -R -o ./cdimage.raw ./directory cdrecord -v speed=8 dev=0,2,0 ./cdimage.raw
and then try the same dd command above using the cdrom as the reader I get
dd if=/dev/cdrom of=isofile
dd: reading `/dev/cdrom': Input/output error 5183+16 records in 5183+16 records out
I can mount the iso file and see that everything is in fact in the file that was on the cd but but why the error when I make my cd and not one from a "valid" source?? Any clues????
Regards Mark
I'll answer this one. It's because the cd was created in tao (track at once mode) instead of dao (disk at once mode).
From the cdrecord author:
The best way to copy a data disk is to copy the raw data on the master CD. This may be done by reading the data from the raw device by using 'dd' or 'sdd'. NOTE: All CD-R's written in Track At Once mode end in two unreadable run-out sectors. For this reason, you will not be able to read such a CD correctly with 'dd'. I recommend to write all disks in Disk at Once mode if your drive is supported in DAO mode with cdrecord. In addition, you may wish to add padding (see cdrecord / mkisofs man pages). Using this command to create the cd works cdrecord -useinfo -dao -eject -pad -data ./cdimage.raw Mark