What Causes Bit Rot?
The most plausible theory right now is the magnetic or electrical charge changed after a long period of time. e.g. the bit 1 slowly lost its magnetism/charge over time and moved to the threshold where it’s interpreted as 0.
This is a reasonable assumption because data is packed denser and denser into smaller and smaller areas, making cross contamination that much easier. To support this theory, you can copy a file to your SSD just once, never used the SSD until years later, only to find corruption in some of the files.
However, in my experience, a computer system is a very complicated beast and the multi-layered interaction and interconnection between hardware, firmware and software can cause problems. Especially when parts of this critical chain of communications gets unmaintained over the years, turned obsolete as other layers are updated and mordernised.
My money is on a obscure bug somewhere that is causing this flip. This bug rarely surface easily, but when it does, the bit flip situation happens. e.g. as data is travelling along the SATA cable, to be written to the SSD, something happened and a bit is flipped during that time.
Corruption may well not be caused by bit rot. Things like anti-virus, and other spy ware that are installed on your system are constantly looking at the things we do. Any of these applications are capable of altering the contents of anything that goes on inside your computer (if they have the access rights) .
Cannot prove any of my theories though.
Regardless of the cause, we know the effects - data retrieved is sometimes not from the same as what is written. You can read more about bit rot here: wikipedia article.
Comment from: Frank Collins Visitor
I don’t believe bit rot is a problem and the Red Book standard copes with missing bits, to a point.
I store all of my music (FLAC, level 8 compression) on a NAS, using FreeNAS. It does a four-weekly scrub which detects and corrects bit rot on the whole file system. While bit rot isn’t a problem for me, it never will be.
It does a four-weekly scrub which detects and corrects bit rot on the whole file system. While bit rot isn’t a problem for me, it never will be.+1. FreeNAS for the win.
A "single-event upset" was also blamed for an electronic voting error in Schaerbeekm, Belgium, back in 2003. A bit flip in the electronic voting machine added 4,096 extra votes to one candidate. The issue was noticed only because the machine gave the candidate more votes than were possible. "This is a really big problem, but it is mostly invisible to the public," said Bharat Bhuva. Bhuva is a member of Vanderbilt University’s Radiation Effects Research Group, established in 1987 to study the effects of radiation on electronic systems.
Here is an interesting YouTube video about bit flipping.