Organization of the file system
mount done immediately because montiruyuschy process can stop the procedure of
opening device or reading the file system superblock, and another process in the
meantime tried to mount the filesystem. The presence in the logical structure
file archive mountpoints requires accurate implementation of algorithms for
performing navigate directories. Point mount can cross in two ways: from the
file system, where the mount, in the file system, which was installed (in the
direction of the global root Sheet), and in the opposite direction. Search
algorithms files should include situations in which a regular component of the
path to the file is the mount point where instead of a regular analysis of the
index node directory accounted superbloka montirovannoy processing system.
Linking files. Hierarchical organization On the basis of the file system tree
structure of modern operating system, does not provide for the expression of the
relationship in which descendants of being associated with more than one
ancestor. Such rigidity partially eliminated the possibility of linking the
implementation of the organization of files or links. The organization links
between catalog and shared file
The kernel allows the user to link directories simplistic writing programs that
require crossing the file system tree. Often, it makes sense to keep under
different names the same team (executable file). For example, the executable
file traditional word processor OS UNIX vi generally may be caused under the
names ex, edit, vi, view and vedit file system. Link between directories and
shared file called context or reference (link). Tree file system becomes a
cyclical Earl. This is convenient, but creates a number of additional problems.
The simplest way to implement a file-linking merely duplicate the information
about it in both directories. In the meantime, however, there may be a
compatibility problem, if the owners of these directories will try independently
of each other to change the contents of the file. For example, if you write to
the file's directory contains addresses directly to disk blocks, as in the OS CP
/ M, copies of the same disc addresses should be made in another directory where
the file linkuetsya. If a user makes an addendum to the file, the new units will
be transferred to him only in the directory and will not be visible to another
user. The problem of this nature can be solved in two ways. First, the so-called
rigid link. If the blocks of data file is not listed in the directory and, in a
small data structure (such as node in the index) associated with the file itself,
the second user can communicate directly with the already existing structure. An
alternative solution is the creation of a new file that contains the path to the
associated file. This approach is called a symbolic link. In doing so,
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