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I have a problems with a burned CD. It does not automatically appear in XFCE (other retail CDs work fine) and I can only mount it by specifying "-t iso9660" explicitly with the mount command. Reading files on it is slow. I have got this kind of errors in dmesg:
[ 604.336979] Buffer I/O error on dev sr0, logical block 204033, async page read
Now my reaction was "this is a bad CD". But somehow I don't think so. I have got the same problem with other burned CDs and moreover:
1) Everything works fine in Windows with the same CD.
2) isosize /dev/sr0 gives: 278659072 which is expected.
3) The readcd command works fine too at high speed. Interestingly, it gives me this message:
Capacity: 138624 Blocks = 277248 kBytes = 270 MBytes = 283 prMB
As you see it reports 138624 Blocks, which seems to correspond to the reality and. The dmesg error appear at 204033 which is after the last block reported by readcd. It seems that somehow the kernel try to read past the end of CD and get errors as expected. Is this is a known bug? Does someone have an idea?
The CD was burned with the same drive. But it didn't works unless I specify the -raw96r option with cdrecord (from cdrtools) (I don't remember the error exactly but it said something like: "please try with -raw96r" which I did).
Last edited by olive (2016-06-27 09:34:51)
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Is this CD an audio or data cd?
Post you cdrecord command string.
From man cdrecord
-raw96r
Select Set RAW writing mode with 2352 byte sectors plus 96 bytes of
raw P-W subchannel data resulting in a sector size of 2448 bytes.
This is the preferred raw writing mode as it gives best control over
the CD writing process. If you find any problems with the layout of
a disk or with sub channel content (e.g. wrong times on the display
when playing the CD) and your drive supports to write in -raw96r or
-raw16 mode, you should give it a try. There are several CD writers
with bad firmware that result in broken disks when writing in TAO or
SAO mode. Writing data disks in raw mode needs significantly more
CPU time than other write modes. If your CPU is too slow, this may
result in buffer underruns. Note that wodim needs to know the size
of each track in advance for this mode (see the genisoimage -print-
size option and the EXAMPLES section for more information).
Haven't written a CD for a while.
Here is from my notes.
Burn .iso to CD
wodim speed=8 -tao dev=/dev/sr0 /path/file.iso
Burn files to CD
mkisofs -J -r -pad -graft-points /path/file /path/file | cdrecord dev=1,1,0 speed=8
genisoimage -J -r -pad -graft-points /path/file /path/file | cdrecord dev=1,1,0 speed=8
Write audio CD
cdrecord -v dev=/dev/sr0 speed=8 -audio -pad *.wav
cdrecord -dummy..... will allow a dry run with no writing to check for errors.
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The cdrecord was the usual one
cdrecord -v padsize=5M dev=/dev/sr0 file-to-burn.iso
But it worked fine with the -raw96r option and I have enough CPU to support the overhead (the CPU was not particularly high when I burned the CD). But the burning seems to have worked fine with this option. The main problem is that there is problem when I read the CD. I don't believe that the burned disk is faulty for the reasons I explained in my question.
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Read the examples section of man cdrecord
It talks about using -raw and drives that need to know the size of a track before starting to write. You have a sector size of 2448.
CD's that I have written have a sector size of 2048
fdisk -l /dev/sr0
Disk /dev/sr0: 281.3 MiB, 294963200 bytes, 144025 sectors
Units: sectors of 1 * 2048 = 2048 bytes
Sector size (logical/physical): 2048 bytes / 2048 bytes
I/O size (minimum/optimal): 2048 bytes / 2048 bytes
You may try burning one with -tao and see if you get better results.
Also is that file-to-burn.iso an .iso of a data cd? You are not trying to mount an audio cd or mixed mode cd?
by specifying "-t iso9660"
So I assume that it's data cd. You could also slow down the burning with the speed= switch
Maybe someone else has more to add.
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Now I have problems in Windows too. All works fine in my old laptop with the same CD. I now believe it is an hardware failure. But it is a very strange way for a CD burner to fail. I was thinking that it was all of nothing but no such weird errors. I mark the thread as solved.
Updated: Definitively an hardware problem. After having replaced the CD burner, all work fine.
Last edited by olive (2016-06-29 09:02:59)
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