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Backup of Images


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#1 NEreswearcher

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Posted 04 August 2020 - 10:42 AM

This is just a heads up for people. I have many many backup copies of all my images so no data has been lost but I did run into a very disconcerting situation. 

 

In 2010 I made several backup copies of all my images to be stored in multiple locations. I wanted to use a lossless format and chose TIFF. After 10 years I wanted to verify that the images were there and perhaps I had missed an image on my online storage.

 

The files are now unreadable after trying multiple machines,  multiple operating systems, and multiple editing program including Photoshop CS5.

 

This is just a heads up that too many copies is not overkill.

 

The good thing is the images that I had saved for my wife are still readable. Whew



#2 Jerry Bryan

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Posted 04 August 2020 - 12:46 PM

Just out of curiosity, are the images from 2010 unreadable because the storage media where they are recorded has become corrupted, or is the version of the TIFF format that was supported in 2010 no longer supported in 2020?

 

Jerry



#3 NEreswearcher

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Posted 07 August 2020 - 05:39 AM

Jerry,

 

It appears that the media is OK but the images are unreadable. I still get  nice directory listing but when trying to open the TIF files they cannot be read the software just clocks and eventually times out or I have to cancel the process. I  tried opening the images with the same software which create them and they are till unreadable.Other images that I stored for my wife's genealogy appear to be OK. The CD I stored the images on is an optical format and I thought that they would be relatively safe from corruption, unlike the magnetic media we also use. I don't have a clue why these are unreadable, they were stored in a climate controlled area with no undue influences from outside sources.

 

My original thought was that everyone should be prepared for this kind of occurrence and have multiple copies in multiple places.



#4 cj1260

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Posted 07 August 2020 - 07:27 AM

I would suspect that the problem is with the CD itself. The writeable CDs used in computers will generally degrade over a relatively short period of time. I have had ones where files began to get corrupted within just a few years. An alternative would be to write the files to an M-Disc using a compatible optical drive...these last much longer.

Your advice about having multiple backup copies is well taken! I would only add that new archival backups should be made every few years since even flash drives and hard drives will degrade over time even if they are stored away and unplugged.

P.S. For what it's worth, the substrates are different between writeable CDs and Music CDs. Music CDs will last many decades if not longer.



#5 TomH

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Posted 07 August 2020 - 11:47 AM

If files became corrupted due to degradation of the medium, the reader should report it as an error. Optical media especially carry a fair bit of overhead for error detection and correction. If a detected error is uncorrectable by the reader, it reports an error.

Tom user of RM7630 FTM2017 Ancestry.ca FamilySearch.org FindMyPast.com
SQLite_Tools_For_Roots_Magic_in_PR_Celti wiki, exploiting the database in special ways >>> RMtrix-tiny.png app, a bundle of RootsMagic utilities.


#6 Bob C

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Posted 07 August 2020 - 02:26 PM

The issue with "Disk Rot" for CDs has been known for many years. It is due to the manufacturing process which lays a lacquer layer over an aluminum recording layer but doesn't seal  the edges. This permits air to start attacking the aluminum recording layer and cause oxidation or pits/holes, which in turn causes the data to become unreadable. There is an archival CD available that uses gold over a special recording layer to slow disk rot for up to 10 years but there has never been a permanent fix. Archival CDs are rather expensive due to the materials and special manufacturing processes. I have read that if you get 2-3 years on CDs that are commonly available you're lucky and should start to convert/copy them to new media.



#7 TomH

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Posted 08 August 2020 - 06:29 PM

If you can copy the files to another drive, then the issue cannot be "disc rot"; it has to be that the format is unsupported by the viewing software. Maybe the encoding software produced a supported format but incorrectly. If you post a file to a shared cloud folder and post the link here, maybe one of us can view it successfully.

Tom user of RM7630 FTM2017 Ancestry.ca FamilySearch.org FindMyPast.com
SQLite_Tools_For_Roots_Magic_in_PR_Celti wiki, exploiting the database in special ways >>> RMtrix-tiny.png app, a bundle of RootsMagic utilities.