The file system is the contents of the notepad, and the file is the word. For hard disks in a PC at the moment, two file systems are most common: FAT or NTFS. First FAT (FAT16) appeared, then FAT32, and then NTFS.
Andrea Fortuna wrote a blog about PowerForensics: the PowerShell infrastructure for forensic analysis of the hard drive. In it, he talks about the PostForensiсs.
The recent most Windows 10 preview is enabling users to change the 260 characters limit.