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Re: CLOSE SESSION failed with SK=5h/INVALID FIELD IN CDB: not harmless?

Thomas Schmitt wrote:

Such a message is rarely harmless.
Well, that's what I thought, but Andy Polyakov commented here:

Oh indeed. Now i remember.
I stepped into that puddle previously.

So for now we count it as harmless.
It is quite out of suspicion anyway. See below.

smally$ sudo cmp /dev/sr1 /video/oldc_backup.udf ; echo $?
/dev/sr1 /video/oldc_backup.udf differ: byte 8585217, line 20010
(my command seemed simpler :-) and as effective)

I wanted to truncate /dev/sr1 to the exact size
just in case all bytes before match the original
and trailing trash would cause false alert.

When I read the block from /dev/sr0 what I get back is all-zeroes. The
corresponding block on the udf image is full of non-zero data.
 the next 2048-byte block following 8585216 on /dev/sr1 is non-zero.

That looks much like a failure of transport or
drive. It happens far before any Close Session failure
could spoil it directly, and it is hard to
imagine how such a final problem should leave
8 MB unaltered and spoil a single block of 2048
If possible try to find out whether there are
more differing blocks in the image.

It is a bit astounding that a first altered
block at that address disturbed the UDF tree
without any error message.
Did you check your kernel logs already ?

Spare Area: 65088/65536=99.3% free Could it be that there was a defect and things were relocated? I don't
really know how the spare area is used.

Actually i never saw it doing any good.

It should be transparent to the reader in any
case. If the drive hands out logical block 4192
then this should be the corrected data which
belong to that address. Any physical address
change should be hidden from the reader.

It seems the Defect Management had reason to
exchange some physical blocks. Of course it
is suspicious if the media shows altered
blocks afterwards. Normally at least the error
detection precautions should have indicated
a failure.
So this could be a failure of the firmware
to correctly perform Defect Management.

Is it possible that this is caused by a relocated block, and for some reason the read is returning the bad block in stead of the relocation? In other words, did this mount somehow tell the device to ignore relocation? Might this be fixed with only a mount option (which I certainly didn't see)?

On BD-RE i normally disable it in favor of
triple speed and own MD5 checkreading.
I have a BD burner and a BD reader drive
so that with bulk backups i reach nearly
triple throughput by simultaneaously
writing and reading.

E. Robert Bogusta
 It seemed like a good idea at the time

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