ibm-information-center/dist/eclipse/plugins/i5OS.ic.ifs_5.4.0.1/rzaaxhardlnk.htm

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<h1 class="topictitle1">Hard link</h1>
<div><p>A <dfn class="term">hard link</dfn>, which is sometimes
just called a link, cannot exist unless it is linked to an actual object.</p>
<p>When an object is created in a directory (for example, by copying a file
into a directory), the first hard link is established between the directory
and the object. Users and application programs can add other hard links. Each
hard link is indicated by a separate directory entry in the directory. Links
from the same directory cannot have the same name, but links from different
directories can have the same name.</p>
<p>If supported by the file system, there can be multiple hard links to an
object, either from the same directory or from different directories. The
one exception is where the object is another directory. There can be only
one hard link from a directory to another directory.</p>
<div class="fignone"><span class="figcap">Figure 1. A directory entry defines each hard link</span><br /><img src="rv3n066.gif" alt="A directory entry defines each hard link" /><br /></div>
<p>Hard links can be removed without affecting the existence of an object
as long as there is at least one remaining hard link to the object. When the
last hard link is removed, the object is removed from the server, unless an
application has the object open. Each application that has the object open
can continue to use it until that application closes the object. When the
object is closed by the last application using it, the object is removed from
the server. An object cannot be opened after the last hard link is removed.</p>
<p>The concept of a hard link can also be applied to the QSYS.LIB or independent
ASP QSYS.LIB file systems and the document library services (QDLS) file system,
but with a restriction. A library, in effect, has one hard link to each object
in the library. Similarly, a folder has one hard link to each document in
the folder. Multiple hard links to the <em>same object</em> are not allowed
in QSYS.LIB, independent ASP QSYS.LIB, or in QDLS, however.</p>
<p>A hard link cannot cross file systems. For example, a directory in the
QOpenSys file system cannot have a hard link to an object in the QSYS.LIB
or independent ASP QSYS.LIB file systems or to a document in the QDLS file
system.</p>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzaaxlinkifs.htm" title="A link is a named connection between a directory and an object. A user or a program can tell the server where to find an object by specifying the name of a link to the object. A link can be used as a path name or as part of a path name.">Link</a></div>
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<div class="relconcepts"><strong>Related concepts</strong><br />
<div><a href="rzaaxconlinkjour.htm" title="If you have multiple hard links to a journaled integrated file system object, all the links should be saved and restored together so that the linkage is preserved as well as the associated journal information.">Considerations for multiple hard links and journaling</a></div>
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