This isn't a direct coding question but more of a OS handling mechanism. I was reading somebody's previous question regarding C# and file handling. Apparently C# was throwing an exception regarding a file being locked when trying to access this. So my question is, does C# use an internal lock to handle file I/O between processes, or does the OS use some type of mutual exclusion for file I/O?

From what I learned about operating systems, well at least unix, is that the OS doesn't implement any type of mutual exclusion for processes trying to access the same file.