how's the OS detects each file and its modifications?
It doesn't. When you edit a file, with most programs, the edited file is written out to a completely new file (with a temporary name), then the old file is deleted, and the temporary file is renamed to the old filename. The *ONLY* link between them is the name.
That's life. Stop wishing for the impossible.
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
In reply to Re^7: Uniquely identifying each & every html template