All the principal information about the file is held in this directory In Unix, all that kind of information is held in the inode. The directory just holds the name of the file and the inode number. The inode method allows multiple links to the same file, as the directories just hold the different file names and the same inode number. When this count drops down to zero, the file is removed. File protection Users of files need some kind of protection mechanism for their files.
Objects belong to one or more protection domains, and in each domain they give access rights.
Similarly, the printer device PRN does not grant delete access in this domain, and it cannot be deleted. On the other hand, it does grant write access, and so you can copy a file to PRN to send it to the printer. Given a particular pair, a list can be made of all files that allow operations to be carried out on them. Every process that runs with that value can access for reading that same set of files. Example Files that are readable by everyone belong to every protection domain for reading.