How does it work?Īt its core, the process is very simple. The process we will examine on this page provides a much higher level of validation. If any change is made to the original file after burning, then you will get a mismatch when comparing, which makes the process much less useful. You could run it again at some point in the future, but it would only give you valid results as long as the original files are never changed. These processes, however, only tell you about the data at the time of the disc burning. The software might even do a bit-for-bit comparison of the original and the copy, which can tell you that the files have been copied perfectly. This might be a comparison of the file size, which provides a basic indication of the burn. When you burn a disc, the software does some level of validation of the burning process. If you have a lot of optical discs, it's probably best to do a random sampling, making sure to choose discs from different eras, and to choose discs from different manufacturers if there is variation in your collection.ĭoesn't my disc-burning hardware do this for me? You'll want to periodically validate your write-once media to make sure that everything's fine. This is the copy you make, put away, periodically validate, and never expect to use, except in the case of some catastrophic loss. It’s probably helpful for most people to consider their write-once copy of the files as a disaster-recovery copy. Once you make any change at all to the files, you invalidate the checksum. #CYBERDUCK DOWNLOAD ALL FOLDERS AND SUBFOLDERS UPDATE#You can also do this with hard drives, but only if you don’t ever update the files once you have created the checksum. Write-once media like CD, DVD or Blu-ray disc is perfect for this, since files on write-once media can't be altered once the disc has been written. #CYBERDUCK DOWNLOAD ALL FOLDERS AND SUBFOLDERS VERIFICATION#And if the files show no change, then you know everything is in exactly the same condition it was in when first stored.Ī checksum-based verification of write-once media lets you know that everything is fine with the files, or that you are starting to have a problem with that copy of the files, and that you need to restore from backup right away. If you remove the possibility of intentionally changing a file, then you can remove any uncertainty about whether the change is intended or not: any change to the file would be an indication of a problem. One of the most vexing problems with data validation is that it can be impossible to tell the difference between an intentional change to a file, and one that may be caused by a computer error, a human error, or a virus.
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