How is it that random bit switches on a computer don’t cause catastrophic failure to an operating system?
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Bit flips aren’t all that common. Additionally, to affect your system they would have to corrupt data that would actually matter to system operation that the system has no handling for. Corruption to a single bit of data has a very, very low chance of actually affecting something important.
Depends on which bit flips; some do cause catastrophic failure, resulting in the need for a hard reset. But in most cases, the result of a bit flip is that a single pixel is a slightly different shade of red, or there’s some static in the audio, or data that’s being processed fails a sanity test and needs to be re-read.
Essentially, most bit use isn’t for the logical operators doing the work; it’s for the data being worked on. And modern computers use caching, so if something goes wrong with the cached data, they just re-read the original data.
As for bit flips on storage media, many file systems have checks in place to catch this, and will re-play the log to repair damaged data. So the only issues arise when there are bit flips in the old AND the new data, or the flip is in infrequently accessed data that won’t be in the change log.
Some file systems also do data hashing to ensure data integrity, but this isn’t usually done on consumer-level file systems.
>ELI5: How is it that random bit switches on a computer don’t cause catastrophic failure to an operating system?
That can absolutely happen. It’s not very likely for multiple reasons though: Bit flips themselves are rare and there is only a limited amount of critical system files with a very limited number of parts that are in active use and only a small number of parts of *those* parts would actually result in some significant failure if changed insignificantly
And even *then* the error will often just be temporary if it only occurred in RAM and caused a crash since everything will return back to normal after that.
You’d have to win some strange kind of lottery to be affected in a significant manner.
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