Browse Prior Art Database

Multi-Symbolic Link

IP.com Disclosure Number: IPCOM000119269D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 3 page(s) / 111K

Publishing Venue

IBM

Related People

Redpath, RJ: AUTHOR

Abstract

Symbolic links are very useful in alleviating "device full" problems and for accommodating for anticipated, non-redefinable names used by applications. The link process is homomorphic.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Multi-Symbolic Link

      Symbolic links are very useful in alleviating "device
full" problems and for accommodating for anticipated, non-redefinable
names used by applications.  The link process is homomorphic.

      The multi-symbolic link can allow for more than one
association.  The link is not read-only.  This means that a new file
can be created under this link, and will reside in the directory
named for the link, if and only if (iff) the file name is not already
defined through the link.  The files which reside under the links
defined by the multi- symbolic link are modifiable.  The
multi-symbolic link is unique in that the name of the symbolic link
is a directory which can stand by itself and it also points to other
directories.  In other words, the multi-symbolic link is a directory
by itself and, if the links are removed, the directory is still
valid.

      A multi-symbolic link is useful for a programmer who
continually accesses files over multiple directories.  For example, a
programmer might frequently view files under the directory
"/ibmc/include/" and "/toolkt11/pm/c/include".  By defining a
multi-symbolic link to link the directories under one name
"/include", the programmer can efficiently find the file under one
name.  For example:
      mlink  /include  /ibmc/include  /toolkt11/pm/c/include

      Similarly, the multi-symbolic link is useful for the end user.
A multi-symbolic link can be defined to access executable files under
different directories defined for unassociated products under one
directory.

      The multi-symbolic link, under BSD versions of the UNIX*
operating system can be implemented with the system's current file
design with very little change.  The aforementioned systems track
files in each directory with a file table which is contained in a
file called "." (dot) which is present in each directory.  The "."
filename is opened with the system function OpenDir() and read with
ReadDir().  Each entry is called a directory entry which is defined
in the "dir.h include" file as a structure.  In this structure there
is a type field which describes the entry as being a directory, a
link, a file and so on.  To implement the multi-symbolic link which
provides the function of a directory and links files in multiple
directories, the following can be done.

      A command must be written which builds the multi-symbolic link
and a new flag must be recognized by the operating system in the
directory entry structure defined by the "include file dir.h".  The
new flag enables the multi-symbolic link to self-update if one of its
links is updated.  This is not necessary if the implementation
requested is to enable the ability for the multi-symbolic link to be
static, thereby providing the user the decision to update the multi-
symbolic link a...