Re: Detect CD Media Type?
Hi,
>
> Now I can detect CD-R, CD-RW very well by -atip
>but are there information about the CD-R is closed, or it's blank, can write
>or not?
>I look and look...but can't find any info about that in -atip
I just compared a used CD-R with an unused one (Platinum cheapos).
There is no difference in the -atip output.
Same with blank/non-blank CD-RW.
I can distinguish them by this shell code snippet which does a 1 byte
test read :
if dd if=/dev/sr0 of=/dev/null bs=1 count=1
then
echo "Has data"
else
echo "Seems to be empty"
fi
It is not dangerous, though, to blank a blanked CD-RW again.
I got no experience with appendable CD-R. (For the purpose of a safe
backup the issue of appending data to CDs is rather counterproductive.)
Maybe you can find a difference in the -atip output :
... burn CD and leave session open ...
cdrecord -atip dev=... >$HOME/atip_session_open
... burn same CD again and close session ...
cdrecord -atip dev=... >$HOME/atip_session_closed
diff $HOME/atip_session_open $HOME/atip_session_closed
>Oh...I forget to ask another question....the info in atip do not include the
>write speed about media, right?
If i only knew.
There are some lines about speed in some -atip output. No idea
wether they are trustworthy and what they actually mean.
In general cdrecord is able to find a suitable speed on its own.
When in doubt, set the maximum speed of your drive. If i give
speed=10 and insert a 4x CD-RW then it gets written with speed 4.
(There is a force option but i can hardly see a good reason to use it.)
Have a nice day :)
Thomas
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