German ... that's why I translated the second part of that page and
added to my mail.
The basic concept is: darktable treats all files as _read-only_ and thus
they are supposed to never change. So if they change something bad had
happened.
So I create a list of checksums of all files in a given directory and
check them from time to time - be it automatically (cronjob or something
like that) or a remark in a calender or by accident - that's left to the
user.
I also have a copy of my archive on at least two other locations - and
there I also check those checksums from time to time.
If something happens at one location I can copy the correct file from
one of the other locations ... but then I should also check if the drive
itself goes eol and replace it.
For me that's a simple concept which I understand - and I like those
transparent concepts :-).
--
regards
Bernhard
https://www.bilddateien.de
Timothy Spear schrieb am 30.08.2018 um 15:58:
Using Google Translate (I am struggling to learn French, no way will I
take on German also!), I think I have a pretty good idea on how you
did it.
Nice solution. Not sure which way I will go, from overkill using
Tripwire, to a custom shell script or a Java/.Net application. I just
know I am not going to try and learn Lua.
Tim
On Thu, Aug 30, 2018 at 2:04 AM, Bernhard
<[email protected] <mailto:[email protected]>>
wrote:
Timothy Spear schrieb am 12.08.2018 um 18:42:
The primary reason I have converted from CR2 and JPEG to DNG
was for the inherit hash embedded in the file which can help
prevent/notify you of bit rot. Since I have previously
experience with bit rot I consider this worth it.
Which reminds me, I need to put in a new ticket issue to
suggest a validation function to dt which will store a hash
for both the XMP and the original image, and can run in a
background process.
That's what I am doing currently with my .NEF and .ORF files:
https://www.bilddateien.de/fotografie/bildbearbeitung/foto-backup.html
<https://www.bilddateien.de/fotografie/bildbearbeitung/foto-backup.html>
Translation of the important part:
Checking data consistency
What does "data consistency check" mean?
For digital data, so-called checksums can be determined by
mathematical methods, which represent a kind of "fingerprint"
for a file. Changing the file, either by processing or by a
data error that has crept in over time, results in a change to
the checksum.
If you now determine their respective checksums for all files
to be backed up and save them, you can check at any time later
whether the files are still in their original state. To do
this, the checksums are determined again and compared with the
values originally calculated and saved. Deviations indicate
file errors.
prerequisites
On the basis of the "non destructive imaging" technique
described above, the consistency check results:
There are a lot of files in the camera raw formats, but
possibly also uncompressed in.tif, which take over the
function of the analog "negative" or "slide" as original
files, can only be read and should therefore not change anymore.
These - and only these - are the subject of the test!
And then there are at least as many of these xml files (2 edit
versions of the same image give 1 raw file and two xml files)
in the same folders, whose characteristic is the change.
Pictures and associated xml-files are typically located in
year folders and there in subordinate project folders.
The check (both the original generation of the checksums and
the subsequent comparisons) should be performed automatically
by software.
Such a software results in a requirement profile:
Program with GUI (graphical user interface - no command
line stress)
Recursive creation and checking in directory trees
(subdirectories are also searched)
Filtering of unwanted file types (here in the concrete
example: xmp (of Darktable), pp3 (of RawTherapee), ...)
possibly different hash functions (mathematical methods
for checksum determination) for selection (crc32 or md5)
if possible cross-platform software (there are versions
for Windows as well as Linux)
An example of a suitable software is Checksum Control.
Translated with www.DeepL.com/Translator
<http://www.DeepL.com/Translator>
--
regards
Bernhard
https://www.bilddateien.de
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