EECS 1012 Lecture Notes - Lecture 11: Symbolic Link, Inode
13 Jun 2018
School
Course
Professor
EECS 1012 Lecture 11 Notes
Introduction
Network file access
• The file creation results in a new i-node, the links now point to different i-nodes and
different versions of the original file.
• In other words, the link is broken.
• Symbolic links work differently.
• With a symbolic link, the new directory entry creates a file that holds a pointer to the
origial file’s pathae.
• Then, when accessing the new entry, the symbolic link uses this file to identify the
original pathname.
• Even if the original file is physically moved, the link is maintained as long as the original
pathname exists.
• Of course, the link is broken if the original file is logically moved to a different directory,
deleted, or renamed.
• In this case, an attempt to reference the file specified by the link will cause an error.
• UNIX does not attempt to keep track of symbolic links, as it does with hard links.
• An additional minor disadvantage of symbolic links is that the symbolic link also requires
the existence of an additional file to hold the link pointer.
• The UNIX system does not attempt to avoid cycles.
• Instead, it restricts access to the linking capability of the system.
• Normal users may only create hard links to files, but not to directories.
• This prevents the normal users from inadvertently creating cycles.
• Only the system administrators can create links between directories.
• It is their responsibility to assure that they do not create cycles.
• One of the primary capabilities provided by networks is the access to files on other
systems connected to the network.
find more resources at oneclass.com
find more resources at oneclass.com
10
EECS 1012 Full Course Notes
Verified Note
10 documents
