Veritas Backup Exec Advance Open File Option: How does it works in the backend, and does it protects unsaved open files?

Hello Friends, If you have any depth understanding of the queries below, please help me with your expert answers.

1. How does Advance Open File mechanism work in the backend of Symantec Backup Exec? A depth technical background of this method...

2. Does it protect unsaved open files? Example: I have an open file and I am continuously writing some data to it, but I have not saved (Ctr+S) this file yet (since 1 or 2 hrs of time). Will it be backed up by Backup exec even if it is not saved to have current modified data with latest contents I have written in this file, or it will just backup this file with what has been already saved (ctrl+s)?

Thanks,
Amit