Re: Archiving content of a directory on a DVD-R.
Hi,
peter@easthope.ca wrote:
> xorriso : UPDATE : Writing: 115440s 29.7% fifo 100% buf 100% 6.0xD
> libburn : FATAL : SCSI error on write(117872,16): [5 21 02] Illegal request.
> Invalid address for write.
That's new to me. I wonder how this could happen.
A DVD-R has to be written strictly sequentially, beginning at its
Next Writable Address as told by the drive. The SCSI WRITE commands
which are issued by libburn are supposed to bear the appropriate target
block address. After each WRITE command the address gets incremented by
the number of blocks which were written.
The code which does this is quite hard to fool.
In principle there are several possible reasons:
- libburn did not increment its WRITE address properly.
- a WRITE command was repeated by libburn or by the kernel.
- a WRITE command was dropped by the kernel.
- the drive's firmware had a hick-up.
Currently i have few ideas how to diagnose this. There is a debug message
in the Linux-specific code of libburn, which might have told more iabout
repetitions if the run had been made with debug verbosity:
xorriso -report_about debug ...other.commands...
But that's quite verbous in many other aspects, too.
I will have to increase the severity of the non-fatal SG_IO driver events.
A repetition would not be noticed on overwritable media. I mostly use
BD-RE and DVD+RW media, which belong to that class. But once per day i
write a BD-R and about every week a CD-RW. Since years.
> libburn : FAILURE : Failed to close session (2). SCSI error : [5 72 03]
> Illegal request. Session fixation error, incomplete track in session.
... and i will have to review the bail-out procedure for failed write
operations. There seems to be missing a close-track operation.
Error handling of rarely occuring problems tends to be buggy by itself.
Have a nice day :)
Thomas
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