3 ms·
What's an example of an error that's undetectable? I'm a little confused about what that means. If an error produces no observable effect, it doesn't seem like
by jxf 5y ago
What's an example of an error that's undetectable? I'm a little confused about what that means. If an error produces no observable effect, it doesn't seem like it matters very much, unless I'm missing something.
- ironmagma 5y agoI assume an undetectable error would be one that cannot be detected except by running the computation again and comparing the results, as opposed to a simple check like a checksum. Or maybe it’s e.g. an error that flips 2 bits, with a 1 bit parity check.
- pdw 5y agoSuppose you protect a piece of data with a checksum. The data gets corrupted and the checksum no longer matches. That's a detectable error. But if you're unlucky, the checksum of the corrupted data matches the original checksum. That's an undetectable error.
- Rexxar 5y agoIf you do a numerical simulation the result could be different than expected but without any easily visible error.
- michael1999 5y agoThey mean that single bit errors are detected in storage systems like ecc memory, or ZFS, and will raise a fault (I.e. be detected). Checksums tend not to follow data into the code. So bit flips in the cpu could do anything at runtime: wrong addition, choosing the wrong branch of an “if” block, etc.