Rosco Bodine
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Forum file attachments problems
This problem persists for file attachments made from
within the message posting window . Files uploaded
using the browse to file to be uploaded and posted are
getting corrupted . But the same file copied onto the FTP
is fine , and the upload/download speed via the forum FTP
is way faster , a hundred times faster .
There has been discussion of the problem in the reference
request thread . The FTP seems to be the only presently viable workaround .
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Sauron
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The file corruption is more usual for zip archives, whereas unzipped pdf files most often are all right.
The corruption does not seem to have been result of use of any particular archiving software, but to be done by the forum server itself.
For example, the identical zip file if uploaded to 4shared or rapidshare, and then downloaded, is fine. But post it to the forum and it cannot be
opened after downloading.
Or, it requires, as kmno4 recently found, an hour's worth of tinkering with the archive to recover the contents, at least one of which is damaged.
kmno4 and not_important can furnish details of the technical aspects of the file corruption, if they are willing.
Sic gorgeamus a los subjectatus nunc.
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Rosco Bodine
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My inclination is to suspect the forum software is causing the issue .
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not_important
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Well, I just tried a 1.185 kb PDF, and it came through intact, downloaded file matched the original.
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Rosco Bodine
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There used to be a 1 Mb file size limit which had a bit of headroom .....but I don't recall exactly how much room .
IIRC it would however flag or not post the attachment at all if the upload limit was exceeded . I can't remember
it simply chopping off the tail end of the file and attaching
the "lite" incomplete version .
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Sauron
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Yes, I agree. That is most likely the case.
It is easily demonstrated.
I can prepare a zip archive from 2-3 pdf's I know to be good.
I can then upload this to my 4shared folder.
I can also upload it to a post in this thread.
And then anyone who wishes can download from both sources and compare the results.
I will call the archive TEST.ZIP and the upload to the forum TESTFORUM.ZIP.
Remember, these start out as SAMW file, and only difference is handling by forum software/server vs handling by 4shared.
Give me a few minutes to make the test file and upload it, and I will return and post it and the link to 4shared.
For this trial I will use the Zip utility built into Windows XP Pro SP2.
The URL to test.zip in my 4shared folder is:
http://www.4shared.com/dir/2245331/5a78115f/sharing.html
And here is the sttachment
[Edited on 2-1-2008 by Sauron]
Attachment: testforum.zip (911kB)
This file has been downloaded 660 times
Sic gorgeamus a los subjectatus nunc.
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not_important
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Chopped 193 bytes off the end of the zip. which is the directory area.
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Sauron
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Sorry for the double post but I did not want to edit the last post after attaching file because that has been implicated previously in corrupting
attached files, and not just zip files.
Anyway, I downloadede testforum.zip from last post. It failed to open.
I then downloaded test.zip from 4shared. It opened perfectlky.
Except for file name they are SAME original file.
So, it is forum software corrupting the archive file.
If anyone doubts my protocol, kindly repeat this test yourself with a zip archive of your own creation.
I think there is now no room for doubt. The forum software is corrupting zip archives.
Shall I test this with an identical archive prepared in WinRAR?
[Edited on 2-1-2008 by Sauron]
Attachment: test.rar (903kB)
This file has been downloaded 624 times
Sic gorgeamus a los subjectatus nunc.
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not_important
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downloaded the test zip (again) and rar. both are broken, the zip definitely has some chopped off the end (in windows use Properties to get exact
file size) and the rar looks as if it got chopped too - the end of the 3rd pdf looks wrong and failed CRC during extraction.
There's a bit of a pause before the files finish downloading, which may have something to do with the problem.
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Sauron
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Same result here. The rar archive opened with an error message but corresctly displayed its directory.
The file ct9191501404.pdf is damaged and will not open. The other two are OK.
As temporary workarounds O suggest
1. If at all possible do not use the forum attachment process, particularly for archive files. Use 4shared or rapidshare or your choice of free
filesharing service (but not mind.net please.)
2. If you must use the forum attachment process, post pdf's one by one NOT as zip archives.
Hopefully will get to the bottom of this.
[Edited on 2-1-2008 by Sauron]
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not_important
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test file 1 mb random binary data from http://www.random.org/files/
the file downloaded is 1,048,406 bytes long, shorter than the original 1,048,576 bytes.
[Edited on 2-1-2008 by not_important]
Attachment: 2008-01-02.bin (1MB)
This file has been downloaded 677 times
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Rosco Bodine
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Another workaround I discovered and posted in the reference requests thread earlier is to copy and paste
the compressed archive to the scipics account on the forum FTP , and then just link to the file . This workaround will be useful for folks who don't
have a file sharing account , and will keep a non-expiring copy of the file
with the forum .
Here's the proof test file that I tried successfully earlier .
http://www.sciencemadness.org/scipics/MSE06.rar
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Sauron
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Could this be a virus, trojan, worm or any other sort of malware infestation on the forum server?
Sic gorgeamus a los subjectatus nunc.
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Rosco Bodine
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Whatever it is has been transplanted through the forum upgrades . And I have noticed that slowdown right at the end of the download for the corupted
files too .
I have a *phat* pipe at about 7.7 Mb/sec , and usually
I just click on the file and it's downloaded completely
before I release the button on the mouse  But for
the borked files it is always slow and getting slower at
the end like the file crawled down in rate and then just died before crossing the finish line .
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kmno4
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| Quote: | | TEST.ZIP and TESTFORUM.ZIP |
Indeed, TEST file is really damaged. But with Power Archiver 2007 program, in this particular case, it can be repaired. In other particular cases
damaged PDF can be extracted and repaired.
Some time ago I uploaded .rar file (3 articles about dehydrating EtOH with CaC2) and it could be downloaded and opened without problems. Now I cannot
unpack all these PDFs - one document is damaged and I am not able to repair it. Propably more sophisticated program is needed for such repairs.
I compared Sauron's TEST and TESTFORUM as .txt files. Somethig ate few characters (propably they correspond to PDF headers only) from TESTFORUM file
and this explains why it can be repaired in that simple way.
This "something" is a forum pixie and I called it Zipeater. Forum is haunted and some exorcist is badly needed, saying apage satana........
[Edited on 14-1-2008 by kmno4]
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Rosco Bodine
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I am unable to access the forum FTP scipics account ,
anybody else having the same problem ?
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S.C. Wack
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An old and unrelated to the above problem that I've had that relates to pdf's (at least) seems worth mentioning in this thread.
That is, pdf's with more than one word download for me (Firefox/XP/Vista) as just the first word, with no file extension. Now these can be opened by
adding .pdf to the word, once saved to hard drive, but I shouldn't (and at an earlier time didn't) have to do this.
But this is only true for say some multiword title.pdf. If it is some_multword_title.pdf instead, (1 word) then there are no problems.
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not_important
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I believe that the file name problem showed up on the version change. Opera seems to work OK. Firefox gives the problem you wrote of, or it calls
the file "viewthread.php", which is the first 'word' in the attachment URL.
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Rosco Bodine
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Let me put it another way . If you click on the following link , what happens for you ? Do you get access or an error message ?
ftp://sciencemadness.org
[Edited on 25-2-2008 by Rosco Bodine]
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Polverone
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Rosco, you need to provide username scipics@sciencemadness.org, and password scipics, when connecting to sciencemadness by FTP. If you just want to
view the contents of the scipics directory, go to https://sciencemadness.org/scipics/.
PGP Key and corresponding e-mail address
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Rosco Bodine
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Yeah , I was trying the login at the main ftp address without and with the directory /scipics and it wouldn't let me access either way ...the server
was connecting , but
wouldn't display the folder. It's working now , but it was
acting flaky , sporadically dumping the logon with a permissions error box popup for awhile . I reset the account and password for automatic logon so
that may have been it .
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kmno4
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It turn out that I can download all attachments and they are not corrupted, but I can do it only on PC at my work.
This PC has much better speed of internet connection (than my PC at home) and it is the only difference (at least it seems so).
During downloading, at its end, "something" strange is occurring - downloading process becomes very slow, almost stops and propably in this moment
file is corrupting. There is no such a phenomena on PC at my work, where downloading is going smoothly to the very end.
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