Rebuild unknown/missing partition table for MO disk

How to use TestDisk to recover lost partition
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Posts: 3
Joined: 16 Jun 2013, 17:05

Rebuild unknown/missing partition table for MO disk

#1 Post by StephenT »

Hello all,

I am attempting to recover medical image files from a backup made onto a (magneto-optical) MO disk. The original backup software/hardware and exact image formats are both unknown, unfortunately.

The MO disk does not mount automatically on Windows, Linux, or OS X. In all situations the disk spins up and the drive shows activity, but no mountable volumes are detected by the OS. OS X's Disk Utility shows the proper size of the media (652 MB, or one side of the 1.3 GB disk), but nothing else.

Here's what I've done so far in Ubuntu:

Found these resources:

- Ran testdisk to analyze the entire disk in the drive, with no partition type selected. Analysis reports read errors in cylinder 1 and cylinders 300-311 of 311, and then does not identify any partitions.

- Ran ddrescue -nv -b 1024 to copy the readable contents of the disk to a .dd file on my hard disk. Same read errors appear at the very beginning (early cylinder), and then at the end of the disk (final cylinders).

- Ran testdisk again on the .dd file, and when using Sun Solaris partition it detects a single partition called "Whole Disk", but when I try to use the "Write" option I get the error "Function write_part_sun not implemented." What does this mean?

- Ran foremost to attempt recovering files by header information, but this returns no recoverable files

I'm stumped. I know I need to recreate the partition table, but if testdisk isn't able to do this, I'm at a loss.

Please help! Thanks in advance.

MO disk details:
Sony CWO-1300B, write-once, 1024 bytes/sector

Hardware Configuration:
Sony Vaio Media Center PC
Ubuntu 8.04
Sony SMO-F551
Adaptec AHA-2930CU SCSI Controller

Posts: 1
Joined: 26 Jun 2013, 14:37

Re: Rebuild unknown/missing partition table for MO disk

#2 Post by RyanL »

Forgive me if I am asking questions that you have already addressed.

I think you are moving in the right direction based on my recollection WORM MO systems were generally Unix based.

Have you tracked down and tried an open source DICOM Viewer?

One particular site that is great for cataloging all the various medical imaging software is, (not affiliated - sorry if links are not permitted) if you could track down the environment that the disk was written with and what piece of equipment wrote the data you might be able to find the correct software for viewing the files at the aforementioned site.

Good Luck, I'm going to bring this up to some of our older techs who have more experience with this stuff. If I have more pertinent information to share, I'll check back with it.

Ryan Libson

Feel free to call me if you have more questions.

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Re: Rebuild unknown/missing partition table for MO disk

#3 Post by cgrenier »

Have you try PhotoRec on the image file ? It recover more file format than foremost.
If it doesn't work, it will help if you can get information about the original file format and backup file format.

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Joined: 16 Jun 2013, 17:05

Re: Rebuild unknown/missing partition table for MO disk

#4 Post by StephenT »

Thank you, Ryan. We've been unsuccessful so far in tracking down the original IT folks who might know more about the creation environment. It just baffles me that something would be so proprietary as to lay down a completely unreadable file system on the disk.

Is there any chance you could put us in touch with someone who might know more about disks and backup practices in the medical industry from this era?

Feel free to email me directly:

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Joined: 25 Mar 2014, 16:47

Re: Rebuild unknown/missing partition table for MO disk

#5 Post by Rickajho »

The problem you are having is that these are driver dependent formats. Early Panasonic MO DOS drivers did not use 1024 sector formatting. (As I recall they were something weird like 1536 SPT. The "hard" sectoring of the media and the SPT formatting are two very different things.) When Windows drivers were released for these early MO drives the Windows drivers SPT formatting was changed and is not backward read compatible with the DOS formatted discs. Even if you thought the partition table was incorrect, and recreated it properly according to how it was originally formatted, you still could not read those discs without the original drivers.

You need to find the original drivers - and a hardware environment to run them in - and you will be fine. But that's the problem: I researched Panasonic looking for drivers a long time ago for someone else trying to recover data from early medical imaging MO discs and never found any.

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Joined: 16 Jun 2013, 17:05

Re: Rebuild unknown/missing partition table for MO disk

#6 Post by StephenT »

Thank you for the reply, Rickajho. We speculated it was something like this. Eventually other versions of the files were found on a different backup medium (yay!), but we were never able to read the MO disks in question. Really bummed that Panasonic (and most companies, for that matter) don't make their legacy software/drivers accessible. Whole swathes of information are becoming unrecoverable by the month, it seems.