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Corrupt Photo CD - COMP.dat / Content.dat

Hi,
Just been handed a CD that contained a lot of photos. The person in question took them on the CD to a supermarket photo printer. Inserted the CD and there is now just 2 files visible a file called CONTENT.DAT (0.16KB) and a COMP.DAT file at 160MB. If I look at the CD using ISOBUSTER I see just one session and the 2 files.
The CD obviously wasn't closed - any ideas on how to recover?
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EirmanChief Operations Manager
Commented:
Try this really excellent free utility
http://www.cgsecurity.org/wiki/PhotoRec

Author

Commented:
Hi,
Already tried it, found it by accident when using the partition recovery software yesterday.

The CONTENT.dat actually contans the following:

Disc = KODAK PICTURE CD
CDVersion = 7.2
ContentVolume = 0
ContentIssue = 0
PCContentRelease = 00.00.02
Region = GBR
Language = EN_GB
Retailer = Max_Spielmann

Which would make sense, can't find a freeviewer though and tried kodak easyshare and nothing
EirmanChief Operations Manager

Commented:
Try a scan with "get data back"
http://www.runtime.org/

You only pay when you can verify that your data is recoverable
Have you tried changing the extension of "Content.dat" to .ZIP and then unzipping it with WinZip, 7-Zip, or Windows own inbuilt function?

Not ON the CD of course, being a Read-Only medium, but with a copy of the file on your hard drive.

A lot of *.dat files are actually some form of proper packaged archive rather than a "data" file as the extension might tend to imply.

When you say: "The CONTENT.dat actually contains the following", are you referring to the Right-Click > Properties of the file, or is this visible plain amongst other garbage symbols having opened the file in a text editor?

160 MB looks to me to be a wrapper/archive with a *.dat extension, that's all.  It could be some kind of proprietory "zip" format, and you might be able to ascertain this by opening the DAT file in a plain text editor and looking for an uppercase acronym at the start of the first line of gobbledegook.

I use Universal Extractor by Jared Breland to unpack a variety of different "package" files.  It uses library functions that enable it to extract from UPX compressed files, most "zip" type formats, MSI and other setup packages, etc, etc.  In fact, it uses a small program named TrID by Marco Pontello to help identify the file type before attempting to extract the contents.

I use the installer version of Universal Extractor purely so that I have Right-Click options as show in the context menu screenshot, but be aware than it does associate itself with some file types that have no association by default and which you may wish to keep that way (eg. *.bin and *.dat files).  In that case you may prefer to use the "portable" version described on the page as the "UniExtract Binary Archive", but I haven't verified whether this still writes to the registry or saves all settings to its own *.INI file.

Try renaming to *.ZIP first and see what happens.  If that fails, open in a text editor and copy and paste the first line of the file here.
Whoopps, I mistakenly referred to "COMP.DAT" as "CONTENT.DAT".

Content.dat looks like it just supplies the Volume Label" etc.

So it's the 160MB "COMP.DAT" that you want to be concentrating on.

Just for arguments sake, 160MB divided by JPG image file size of 1.5MB for a reasonably good photo = 106 images.

There could be some file compression at play, and taking into accounts overheads for other files that may be in the *.DAT file like an *.exe "viewer" and maybe some HTML help pages or similar, do you think that there should be something like 60 to 100 images on that photo CD?

If so, they are in "COMP.DAT".

Author

Commented:
Hi,
Thanks, tried the extractor you mentioned and it doesn't work. The contents of content.dat are exactly as follows.

Disc = KODAK PICTURE CD
CDVersion = 7.2
ContentVolume = 0
ContentIssue = 0
PCContentRelease = 00.00.02
Region = GBR
Language = EN_GB
Retailer = Max_Spielmann


Regards
Mike
Yes, sorry Mike, I accidentally transposed the file names in my first comment, and then corrected this in my follow up.

The file "content.dat" looks like it just acts as a reference file for identification purposes, hence the small size of 0.16KB.  It is the "COMP.DAT" file that is 160MB and surely holds a lot more than just lines of plain text information.

Are you saying that you DID try to unpack "COMP.DAT" without success, and you are just reiterating that the other file (content.dat) contains readable lines of text?
Content.dat really just looks like a file that provides "Properties".  Sometimes Photo CDs created by companies include their own viewer program, and they think they are clever by trying to flout copying of contents by placing upside-down images on the CD that are automatically corrected by the viewer program.  I would have expected that a CD of any kind would have a hidden "autorun.inf" file in the root of the disc that contains the instructions to run a little *.exe file which (I guess) would then access the contents of the *.DAT file.

If you look at CDs like the old Microsoft AutoRoute and Encarta, they have large *.DAT files (perhaps by another extension, I can't remember).  These are not unpacked when the resources such as images, audio, video, etc are needed.  The small RunTime program can access the contents from within the DAT file.

Is it possible that you are not seeing hidden files on the CD because your Windows Explorer ptions are set not to display hidden files?

Author

Commented:
Hi,
I did double check, but they are the only 2 files on the disc. I also checked and the disk has not been closed (CDR).
hanks
M
Mike, I just noticed that I used the wrong description for this kind of CD in referring to it twice as a "photo CD".  Just for clarity, the Kodak "Photo CD" format is completely different from the "Picture CD" format.  The former, which clearly is what you have, should be a closed multisession CD-R containing viewing software and pretty standard JPG images, whereas the latter is a very proprietory format that uses *.PCD image files;

Comparison of the Kodak "PICTURE CD" and "PHOTO CD":

http://www.kodak.com/global/en/service/professional/tib/tib4164.jhtml?id=0.1.14.34.5.80&lc=en

http://www.osta.org/technology/cdqa9.htm

http://tedfelix.com/PhotoCD/PCDMakeYourOwn.html

Form that last page I found what I was looking for, and it is what your CD should most likely contain:

http://tedfelix.com/PhotoCD/picturecd.html

Your version is 7.2.  If the layout of a version 6.0 CD remained unchanged through to version 7.2, then you are missing a text based "INFO.CD" file and a FOLDER named "PICTURES" containing standard JPG images.

This doesn't change my theory that the file "COMP.DAT" actually IS your "folder" of images.

I wonder what would happen if you copied "COMP.DAT" to your hard drive, removed the Read-Only attribute, and renamed it just losing the *.dat extension?  I doubt it would suddenly start behaving as a folder, but just curious to see what its properties would show.

I also wonder if it might be possible to create an exact copy of the CD using the Disc Copy function found in most CD Burning software, and then use that same software to try and finalise the copy?

Just thinking out loud here.  I would really love to be able to have that large DAT file in front of me to mess with.  

Author

Commented:
Hi,
Agree with you about comp.dat and had already tried it without an extension on the filename. I will try a copy and see what happens.
Thanks
M

Author

Commented:
Hi,
Tried the copying and closing the disk and it is still the same,
Mike

Author

Commented:
I couldn't get any data back, but thanks for the help. I split the points as fairly as I could.
Thank you Mike