Better explanation of meaning corrupted and changed

Can man page explain better (in technical terms) what corrupted and changed means?

I found some explanation on stackexchange:

* https://unix.stackexchange.com/questions/438449/f3read-what-is-the-difference-between-corrupted-changed-and-overwritten-secto

But I feel it is lacking core part about how f3write works and it should explain algorithm how it writes the data.

I can understand when CPU send wrong data, or when data stored incorrectly. Would be nice instead "Slightly changed" it could use common term like CRC error. Or corrupted like BUS transfer error (or END to END error like in SMART terminology)

* https://ru.wikipedia.org/wiki/S.M.A.R.T.

EDIT: I had to check source code and find out this is all nonsense. Here is no END to END error checks. No way this is should be in the code. Basically here is no difference between changed / corrupted. Simple CRC errors:

```c
else if (error_count <= TOLERANCE)
stats->secs_changed++;
else
stats->secs_corrupted++;
```