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Topic: Corruption of file
Replies: 3   Last Post: Dec 19, 2012 4:56 AM

 Messages: [ Previous | Next ]
 Alexei Boulbitch Posts: 483 Registered: 2/28/08
Re: Corruption of file
Posted: Dec 18, 2012 2:35 AM

Dear David, dear John, dear Helen,

Yes this file is very valuable. In fact it is one of the files, where I collect tips and tricks on Mathematica learned from others or invented by myself, but those that I have at least once successfully tried. It enormously accelerates my work.

And for this reason, yes, I made a backup rather recently, so I have not lost a lot. I had already such an event once, few years ago and then I lost alot of valuable information: a lecture prepared during several days.

David, none of the scenarios proposed in your mail was the case. Just in a fresh notebook I made a cell with a simple code illustrating the new way of the use of LineLegends and Placed statements in M9 like this:

Plot[{t*Exp[-t], Sin[t^2]}, {t, 0, 2 \[Pi]}, PlotStyle -> {Red, Blue},
PlotLegends ->
Placed[LineLegend[{Red, Blue}, {"exp", "sin"},
LegendLayout -> "Column"], Scaled[{0.15, 0.2}]]]

and evaluated it successfully. Then I copy-pasted this cell into another notebook, the one in question. This time it was a very large notebook, where I made a separate cell for this example. I also inserted two comments of the form (* a comment *) like this:

Plot[{t*Exp[-t], Sin[t^2]}, {t, 0, 2 \[Pi]}, PlotStyle -> {Red, Blue},

(* the Legend starts here *)
PlotLegends ->
Placed[LineLegend[{Red, Blue}, {"exp", "sin"},
LegendLayout -> "Column"], Scaled[{0.15, 0.2}]]
(* The Legend ends here*)
]

and again evaluated it, this time in the large notebook. In the process of this second evaluation I have got the message described below, and the notebook got corrupted.

First I thought that this may be the comment problem (as described by Fred Simons few days earlier). For this reason I tried to make the same code with comments in another (fresh) notebook and evaluate it. It evaluated successfully.

I tried the way proposed by Helen Read (see below), it did not work in M9.

I tried to open the file by the Notepad and cut away the mentioned piece of the text: bdnhsNoXjUtzE3OjHyBhBxTcduHehni+. It did not help. I tried to find and cut away the whole new cell, but did not really succeeded to find where the cell starts and stops. The more that I am not sure that the corrupted part is in that cell.

John, I tried to send you the file, but the server rejected my mail saying that your address does not exist. I will try again later.

My question is not that much about how to open just this file. It is more general: what could be done in such a case? Just in case it will start happening.

Best, Alexei

On 11/12/2012 07:24, Alexei Boulbitch wrote:
> Dear community,
>
> During the work evaluation a cell I got the message:
>
> "There is a syntax error in the file being read. Do you want to open it as
> a plain text?"
>
> Upon pressing "Yes" I got the message:
>
> "There was a syntax error on line 541095 in the file: 2Dgraphics.nb.
> The error was:
>
> bdnhsNoXjUtzE3OjHyBhBxTcduHehni+"
>
> And the question, if I wish to open it as a plain text file. Upon the pressing the "Yes" button the hang up starts.
>
> The file in question cannot be open by Mathematica any more.
>
> It is Mathematica 9 on Windows XP.
>
> Alexei BOULBITCH, Dr., habil.
> IEE S.A.
> ZAE Weiergewan,
> 11, rue Edmond Reuter,
> L-5326 Contern, LUXEMBOURG
>
> Office phone : +352-2454-2566
> Office fax: +352-2454-3566
> mobile phone: +49 151 52 40 66 44
>
> e-mail: alexei.boulbitch at iee.lu<mailto:alexei.boulbitch at iee.lu>
>

Quite apart from the failure to open the file as plain text - which is
not really that useful, because it will display BoxForm structures -
there are surely two important questions:

1) Do you have any idea what caused the corruption?

2) Is the notebook important to you, and if so, is it backed up?

Unless this is a bug in Mathematica 9, this sort of thing can happen if
a notebook is written back to a disk just as the system is shut down (or
a removable disk is pulled out).

If you need the data that has been corrupted, you can probably retrieve
most of it using a text editor on the file. Try opening an uncorrupted
notebook with a text editor to see what they contain.

David Bailey
http://www.dbaileyconsultancy.co.uk

I didn't notice your original post or I would have replied earlier, but I just saw David Bailey's response. I have some tools which are pretty good at cracking file corruption. If you send your notebook to me, I can try to recover it for you.

John Fultz
jfultz@wolfram.com
User Interface Group
Wolfram Research, Inc.

The following sometimes works (I have not tried it in v. 9 however):

In a new notebook:

<<AuthorTools`

NotebookRestore[]

This will open a window for you to find and select the notebook you wish to restore.

Good luck

University of Vermont

Alexei BOULBITCH, Dr., habil.
IEE S.A.
ZAE Weiergewan,
11, rue Edmond Reuter,
L-5326 Contern, LUXEMBOURG

Office phone : +352-2454-2566
Office fax: +352-2454-3566
mobile phone: +49 151 52 40 66 44

e-mail: alexei.boulbitch@iee.lu

Date Subject Author
12/11/12 Alexei Boulbitch
12/14/12 David Bailey
12/18/12 Alexei Boulbitch
12/19/12 David Bailey