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On 16/08/11 02:33, Twayne wrote:
In news:4E4867E6.8030804@botanicusaustralia.com.au,
Simon Cropper<scropper@botanicusaustralia.com.au>  typed:
On 12/08/11 14:38, planas wrote:
On Fri, 2011-08-12 at 13:52 +1000, Simon Cropper wrote:

Hi Everyone,

I have been doing some follow-up investigations that I
thought you might like to be made aware.

First, why? Well after testing the file that I
recreated by copying the text, formula and styles I
could not cause the error to occur again. This is what
I reported yesterday. I then proceeded with importing
the few images and 'artwork' objects from the old file
to the new. After several saves and sheet manipulations
I noticed the file became unstable again. The outcome of my
investigation was that one of the
image files used on one of the sheets had become
corrupted* and adding this file in caused the file to
become unstable - eventually exhibiting the problem I
mentioned about not being able to save after a sheet
was deleted. These 'corrupted' files are relatively
benign with the error only becoming apparent *once* you
attempt to delete the sheet. So somehow the error
caused problems with the broader 'workbook' structure
not the sheet structure. Although I compared files
between different versions of the file the XML were too
varied (usually style names and definitions; content
was identical).   * note I say corrupted but it rendered OK and only
      resulted in the observed behaviour one a sheet is
      deleted. I 'deem' it corrupted as once replaced
      with a clean version render and saved as a new
file by GIMP, the problem disappeared. The error was with the particular
corrupt objects. On
recreating new images and inserting them into a file I
have not been able to trigger any problems. If I
cut-and-paste from the original 'corrupt' file the file
becomes unstable after a few saves and sheet
manipulations.  So the steps for salvage is...
1. recreate a new file with the exact number of sheets
as the original. Ensure each sheet names are the same.
2. Cut and Paste each sheet. Make sure you 'Paste
special' limiting the content being placed in the new
file to text, numbers, date&   time, formulas and
formats. 3. If you have images in the file. Recreate / Save
using another package. As mentioned I used GIMP.
4. Insert new copies of the images into file. *Don't*
cut-and-paste objects from the old file.
5. If you have any lines, text boxes and artwork;
recreate them from new. During this process...
- Save as a new version (+tabs, +data, +images, +other
objects) following each step.
- Test each version thoroughly before proceeding.
- Only add one object at a time, so if something goes
wrong you can isolate the problem component.
- To check it is not a bug try and recreate with a
fresh file. A couple of quick notes that may be valuable to
others... - ODS files are archives. Use an archive
facility to extract the data inside. Inspect the
contents in the folders to see what is different. - On
every 'Save as' the file size changes. This is not due
to changes in the file contents, but rather in changes
in how the components of the file is
compressed/archived. If you open a file, add objects
then save, the file size with be so big. Open that file
and "Save as" a new name and the file will be a
different size. If you extract the files the contents
of all the files and directories are identical. It is
just the internal archive facility in LO will decide
the best compaction routine based on what it
encounters. - The content.xml file can be quite large
and has no internal end-of-line characters. This make
it difficult to open and be parse by various text
editors, xml viewers and comparison facilities. To
insert a EOL character after the end of each tag
(i.e.>), I used the following command in the terminal
(requires Linux).     cat content.xml | sed -e 's/>/>\n/g'>
content_with_linebreaks.xml cat just spews the content of the text file
to the
      standard output. I then pipe it to sed, where I
      used regular expressions to find '>' and replace
      every instance of it with '>\n'. I then compared
the contents with Diffuse.

Snip

+1

I wonder how the images got corrupted, interesting.

Good question and something I was not happy just leaving
alone.
Once I satisfied myself that this was most likely not a
bug but file corruption the questions that came to mind
were... (1) How this file became corrupted? and
(2) How extensive is the damage (physical damage, system
wide, file specific)?

As mentioned I currently use Linux so needed to find a
method to check the file system for errors and see if any
blocks or clusters were damaged. I am assuming here that
I could of had a power spike or jolt to my machine that
could of caused the platter on my hard disk becoming
damaged.
I did this by running 'fsck.ext4' from a LiveCD on all my
hard disks. It took all Saturday to do this. Thankfully
no errors were detected. Anyone interested in how I did
this can check out my more specific response on the
Ubuntu Forums...
http://ubuntuforums.org/showthread.php?p=11152491#post11152491

This left me with an event that could have occurred while
the affected file was open that could have resulted in
the identified corruption. In fact, on reflection I did
have a power blackout 3-weeks ago! I know pretty much
exactly when it occurred and so was able to work out
exactly what I was doing... as it turns out I was editing
the exact sheet in the corrupted file that contained the
corrupted image!
As LO had 'recovered' the file; all text, formula and
images were present and encountered for; and rendering as expected, I
never even thought the file was damaged; so much so that
2-weeks later when peculiar 'sheet/tab deletion errors' appeared I did not
even connect the two events (power outage and corruption).

Thanks everyone for your help - I appreciate your efforts
and suggestions.


What does "could of" mean in the context of your usage? It makes no sense.
Could "have" would make sense, but several times you said "could of".


Hello Twayne,

Thank you for your feedback, albeit off topic. I take your point and will endeavour to ensure my colloquial tongue does not make it to the page again.

I find it a bit pretentious though that you ask what is obviously a rhetorical question - a gibe at the tail end of a lengthy technical discussion - on an international mail list dedicated to discussing the use of a particular program (rather than say a list that is discussing 'grammar' or 'English Usage') and personally I consider it bad etiquette (akin to FlameBait [1]); a polite email to me privately would have sufficed, if you actually did not know what I was saying.

In future, if you have the need to surreptitiously dress down someone for a spelling mistake, a grammatical error or maybe an unusual writing style, please refrain yourself from doing it. Participants on most mail lists come from a wide variety of backgrounds and do not appreciated being belittled in public.

[1] http://en.wikipedia.org/wiki/Flaming_%28Internet%29#Flamebait

--
Simon

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