I'm not a professional photographer but I do value my photos very much. Sometimes when I look through them months or years after I've taken them, some of them just show up corrupt for no evident reason. I often get things such as gray areas, altered colours starting from a certain point on or even completely undisplayable photos. I use both Windows and Linux OS on my PCs.
Why does this happen and, most importantly, how to avoid this?
Answer
There are two main causes. The first is data degradation. Bits stored on magnetic media (such as your hard disk) can lose their magnetic orientation over time, corrupting the bit. In harsher conditions (high heat and humidity) the physical media itself can start to degrade. For solid state media such as an SSD, the mechanism is different but the outcome is similar.
The more common occurrence is silent data corruption, whereby an error occurs during the writing or reading of data. Though the image at the previous link is an extreme example, oftentimes a single flipped bit can corrupt an image.
There are two solutions to these issues, and assuming you rotate your backups, backups alone won't help. The more complicated and technical approach is to use a filesystem with built-in data integrity mechanisms (such as ZFS or btrfs), while a simpler approach would be to compute a hash for each file between backups to detect any changes.
No comments:
Post a Comment