Re: Problem mounting encrypted blu-ray disc or image
Hello again
First of all, I tested all my BD backup discs now, and there are no problems
from #1 (2017) - #12 (05/2018) as well as #14 - #17 (2019-05/2020).
# 13 from 03/2019 fails.
#1 to #10 are all from 05/2017, they're the first BD backup at all and I assume
I used some manual workflow back then to start with; they also contain only
pictures, not my current larger set of files.
Then there's #11/#12 (2018), #14/#15 (01/2020) as well as #16/#17 (05/2020),
with each of these pairs being completely ok.
Afterwards (#18 - #22) there is a pattern such as
#18 (disc 1 of 2 for 01/2021) fails
#19 (disc 2 of 2 for 01/2021) is ok
#20 (disc 1 of 2 for 07/2021) fails
#21 (disc 2 of 2 for 07/2021) is ok
#22 is disc 1 of "NA" for 06/2022: I noticed the problem and didn't
continue...
I use git for my script, but only since 2020; there's no change to my IMGSIZE
setting in the git log, so this cannot explain why #11 - #17 are ok, #18
starts failing. #13 from 2019 is kind of an outlier.
I'm going to try a new full (not incremental) backup, spanning multiple discs,
in the near future and test my script thoroughly... but before, I'll add an
option to it which allows to modify the "last backup date" value stored in the
extended attributes of the filesystem for all backuped folders. That's the part
I really like: I can see very easily in a file manager (dolphin in this case),
which folders are backuped and when the last backup has been done.
Best,
Bernd
On Montag, 11. Juli 2022 10:10:51 CEST you wrote:
> Hi,
>
> B.M. wrote:
> > Do I understand correctly, you say that this Pioneer drive doesn't work
> > well with Verbatim BD-RE, i.e. their rewriteable BDs.
>
> Yes. The problem is with the high reading speed of the drive and with
> a physical flaw of Verbatim BD-RE (CMCMAG/CN2/0).
> The flaw is that there are letters engraved in the transparent area around
> the inner hole, which reach to the thickened ring around the hole.
> This ring is obviously essential for physical stability and the letters
> weaken it enough so that 10 to 20 full read runs on my Pioneer BDR-209
> are enough to produce a radial crack at the hole. This crack grows towards
> the rim in a few more full speed reads. As soon as the dye is reached, the
> medium is unreadable.
>
> Writing is no problem, because it happens at most at 2.0x speed.
> Older Verbatim BD-RE (VERBAT/IM0/0) are no problem. But one cannot buy
> them any more.
> Reading the new Verbatim BD-RE media is no problem on Optiarc BD RW
> BD-5300S, LG BD-RE BH16NS40, and ASUS BW-16D1HT. And of course not with the
> old LG drives like BD-RE GGW-H20L which read (and write) BD-RE at 2.3x
> speed.
> > Since I only use BD-R, it
> > doesn't matter for me and my use case, but thank you nevertheless.
>
> I tested about 50 reads with RITEK/BR3/0 and Verbatim CMCMAG/BA5/0
> BD-R media. No problems. (And no engraved letters to see around the
> inner hole.)
> The media which you inspected by dvd+rw-medianinfo are CMCMAG/BA5
> (dunno what dvd+rw-medianinfo did to the "/0" part of the name).
>
>
> I am still curious whether the decryption problems are caused by
> not closing the /dev/mapper device.
>
>
> Have a nice day :)
>
> Thomas
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