How to solve such a problem?

Question

linux

There was a problem with reading from a file using fread. It seems to return the required number of bytes, but the byte values ​​are sometimes not the same. Have you ever had this?
It is thought to use read from posix. But on the other hand, why does such a fierce programming language as C have unfinished functions?
Or maybe it's a hardware problem? Some sort of RAM error?

I ask the moderators not to remove the "linux" tag.

Answer 1

"sometimes" is a qualitative category. And the question should be - quantitative. For example - called fread() a hundred times, got the text "ass" 90 times and "ass" ten times...