[Debburn-devel] Burning corrupted data CDs with wodim

[Thomas Schmitt]

Hi,

> There is no error symptom during the burning phase but when inserting the
> CD, it can't be mounted.
> [...]
> Jul 21 00:18:03 bouzin kernel: [17571.002253] sr 1:0:1:0: [sr0] Sense Key :
> Medium Error [current] 
> Jul 21 00:18:03 bouzin kernel: [17571.002265] Info fld=0x55737 
> Jul 21 00:18:03 bouzin kernel: [17571.002269] sr 1:0:1:0: [sr0] Add. Sense:
> L-EC uncorrectable error 
> Jul 21 00:18:03 bouzin kernel: [17571.002281] sr 1:0:1:0: [sr0] CDB:
> Read(10): 28 00 00 05 57 36 00 00 02 00 
> Jul 21 00:18:03 bouzin kernel: [17571.002301] end_request: I/O error, dev
> sr0, sector 1400024 
> Jul 21 00:18:03 bouzin kernel: [17571.002316] Buffer I/O error on device
> sr0, logical block 175003

This is a message forwarded from the reading
drive. It says that the drive detected a checksum
error when attemping to read sector 0x55736.
That's CD sector 350006 = byte 716,812,288.

It seems that not wodim is to blame but the
combination of drive and CD.


> I've got grounds to suspect the issue is wodim-related.

Checksum errors are not the fault of the burn
program as long as plain data are written.
In that case, the checksums are to be computed by
the drive.
(There are other CD write modes where the burn
 program computes the checksums.)

> It just worked with Xfburn, so I assume the CD-burner is not guilty.

Thank you for using a libburn based program :)

I would love to claim superior quality, but in
this case it must have been a mere incident that
the one CD is ok and the other is not.


Your syslog at
  https://bugzilla.gnome.org/show_bug.cgi?id=620467
reports:
> Jun  3 12:11:05 bouzin kernel: [ 6792.318169] sr 1:0:1:0: [sr0] Sense Key : Blank Check [current] 
> Jun  3 12:11:05 bouzin kernel: [ 6792.318180] sr 1:0:1:0: [sr0] Add. Sense: No additional sense information
> Jun  3 12:11:05 bouzin kernel: [ 6792.318190] sr 1:0:1:0: [sr0] CDB: Read(10): 28 00 00 00 00 00 00 00 01 00
> Jun  3 12:11:05 bouzin kernel: [ 6792.318209] end_request: I/O error, dev sr0, sector 0

"Blank Check" (Sense Key 8 as of SPC-3) means:
"[...] that a write-once device or a sequential-access
 device encountered blank medium or format-defined
 end-of-data indication while reading or that a write-once
 device encountered a non-blank medium while writing."

So if it is sure that the media was written, then
the drive seems to go blind.
It is not clear whether it loses its ability to
write or its ability to read properly.


Proposal:
Try to read older CDs which once worked fine.
Try to read the problematic CD by another
computer or drive.
Try to write other brands of CD.
Try to write with another computer or drive.

A single success or failure does not say much.
One can easily get lured into false impressions.
Three successes resp. failures in a row would be
more significant.


Have a nice day :)

Thomas