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Hi

I have an old data CD ROM which was created on an external Iomega "Zip 650" USB CD/DVD RW drive similar to this one:
https://www.amazon.co.uk/Iomega-650-DVD ... B002LI1NDM
created in Windows 95 I think...

Various multimedia files (.mp3, .jpg, .doc) were burned to the disc.
The disc was not finalised following burning, as I'd planned to add other files to the archive at some point.
I am not sure whether this makes recovery of files more difficult ?

The disc was subsequently lost for >20 years, until I found it last month, covered in scratches and apparently unreadable.

I am now using Ubuntu (Peppermint 32 bit Xenial) and no longer have a PC, or the Iomega drive that created the CD-ROM.

I polished the CD-ROM, and was then able to read most of the sectors of the CD by using an external CD drive and 3 incremental passes of safecopy, and saved the files to my HDD as an iso disc image using:
~$ safecopy /dev/sr0 /new.iso

However I am unable to mount or read the resulting disc image on my HDD using Ubuntu Archive Mounter via the GUI.
There is no error message; but the image will not open either.

(I have also tried to read the iso file by running the PC app IsoBuster 4.6 in Ubuntu using Wine. It reads the iso file but is unable to find any file details)

I have therefore tried to use testdisk:
~$ testdisk new.iso
This returns:
Disk new.iso - 275 MB / 262 MiB - CHS 34 255 63
Partition sector doesn't have the endmark 0xAA55

And have tried to retrieve the files from the iso archive by using photorec:
~$ photorec new.iso
This retrieves several hundred fragments of txt files of <1.5 kB , and fragments of mp3 files < 90kb.
The resulting txt files do contain readable text which opened with a text editor, but only a paragraph or so of text per file; and the mp3 files are playable, but just a few seconds duration per file.

I suspect there is nothing of significant value on the CD-ROM - just a few personal photos and documents etc; but it would nice to retrieve the full files if possible; and it would be really helpful for my own education to learn more about using testdisk and photorec in case I have a similar situation in future.

I have read the Step-by-step guides for both testdisk and photorec on this site, but I'm not sure what file system the Iomega Zip CD burner used; whether testdisk or photorec is the best tool to recover files in this case; and if so which advanced options I should use with either app to open my disc image and retrieve full files rather than multiple small fragments.

I would be very grateful for your expert advice and guidance.

Many thanks in anticipation

David
(Wales, UK)

Testdisk does not support the ISO file system or any of their followers.Testdisk only supports hard drive file systems.

To create an image use H2cdimage, Unstoppable Copier oder DVDDisaster. If the program allows it, redo the recovery on different drives to get hold of the missing sectors.
I don't know which recovery software is able to work on an incomplete ISO file.
Depending on the extent of dammage you might mount that ISO file and recover some files.

Many thanks for your speedy and helpful reply.

Using incremental passes of safedisc from Ubuntu's command line interface worked well to retrieve nearly all of the data from the physically damaged portions of the CD by trying multiple passes and head alignments of the CD reader; so I don't think I'll get a better result with other software such as Unstoppable Copier, as I believe that this works in a similar way.

As you say, the problem is now that I have a corrupted ISO file saved as a disc image.
I can't open the image file to mount or explore it in Ubuntu; and it might not be possible to use testdisc or photorec to recover the files.

So my questions are now:

1) What are the consequences of failing to finalise a writable CD-ROM ?
Can it cause the ISO file to become corrupted and/or make data recovery more difficult if there is physical damage ?
2) Are there any Advanced options in testdisc or photorec which might help read a corrupted ISO file ?
3) I'm aware of other Linux 'file carver' recovery tools such as Scalpel and Foremost - would these be worth trying, or are they unlikely to work if photorec does not ?
4) Is there any other data recovery software which can mount and read a corrupted ISO file ?

I'd be grateful for answers to the above, or links to tutorials to help my understanding.

Thanks again for your expert help

Kind regards

David

Dave67 wrote: 01 Nov 2020, 11:25 1) What are the consequences of failing to finalise a writable CD-ROM ?

I don't know because I am not familiar with the on-disc format used. It may depend on wheter it's only an end-marker or some structural information like a boot sector, p.e.

Can it cause the ISO file to become corrupted and/or make data recovery more difficult if there is physical damage ?

See above.

2) Are there any Advanced options in testdisc or photorec which might help read a corrupted ISO file ?

recuperation wrote: 31 Oct 2020, 19:33 Testdisk does not support the ISO file system or any of their followers.Testdisk only supports hard drive file systems.

No. For Photorec ist must be difficult to determine if a file within an ISO file belogs to the ISO file or is a regular file on the same level as the ISO file itself.

3) I'm aware of other Linux 'file carver' recovery tools such as Scalpel and Foremost - would these be worth trying, or are they unlikely to work if photorec does not ?

I don't know.

Thanks for your speedy reply, and for your generosity in making this amazing software available to everyone.

If anyone else reading this has answers to the questions in my last post, please let me know by replying to this thread.

Best wishes

David