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| author | Frank Baker <fbaker@hdfgroup.org> | 2005-07-19 17:28:56 (GMT) |
|---|---|---|
| committer | Frank Baker <fbaker@hdfgroup.org> | 2005-07-19 17:28:56 (GMT) |
| commit | 794ba0a251af47b8e3c60afa2fe92d267e2a6b55 (patch) | |
| tree | f24cea3b81ff02fa3f31c0a1c4e80fa10f4393c0 /doc/html/MountingFiles.html | |
| parent | d2e92fd23610c3ccdddbbc55484e54a5a21a9252 (diff) | |
| download | hdf5-794ba0a251af47b8e3c60afa2fe92d267e2a6b55.zip hdf5-794ba0a251af47b8e3c60afa2fe92d267e2a6b55.tar.gz hdf5-794ba0a251af47b8e3c60afa2fe92d267e2a6b55.tar.bz2 | |
[svn-r11084]
Description:
All HDF5 user documentation has been moved to a separate hdf5doc/
repository, managed under Subversion.
With this 'cvs commit', all files are stripped from hdf5/doc/.
THIS CHANGE IS APPLIED ONLY TO THE HDF5 DEVELOPMENT BRANCH,
post Release 1.6.x; it is not applied to the release branches.
Diffstat (limited to 'doc/html/MountingFiles.html')
| -rw-r--r-- | doc/html/MountingFiles.html | 427 |
1 files changed, 0 insertions, 427 deletions
diff --git a/doc/html/MountingFiles.html b/doc/html/MountingFiles.html deleted file mode 100644 index 16f9115..0000000 --- a/doc/html/MountingFiles.html +++ /dev/null @@ -1,427 +0,0 @@ -<html> - <head> - <title>Mounting Files</title> - -<!-- #BeginLibraryItem "/ed_libs/styles_UG.lbi" --> -<!-- - * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * - * Copyright by the Board of Trustees of the University of Illinois. * - * All rights reserved. * - * * - * This file is part of HDF5. The full HDF5 copyright notice, including * - * terms governing use, modification, and redistribution, is contained in * - * the files COPYING and Copyright.html. COPYING can be found at the root * - * of the source code distribution tree; Copyright.html can be found at the * - * root level of an installed copy of the electronic HDF5 document set and * - * is linked from the top-level documents page. It can also be found at * - * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html. If you do not have * - * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. * - * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * - --> - -<link href="ed_styles/UGelect.css" rel="stylesheet" type="text/css"> -<!-- #EndLibraryItem --></head> - - <body bgcolor="#FFFFFF"> - - -<!-- #BeginLibraryItem "/ed_libs/NavBar_UG.lbi" --><hr> -<center> -<table border=0 width=98%> -<tr><td valign=top align=left> - <a href="index.html">HDF5 documents and links</a> <br> - <a href="H5.intro.html">Introduction to HDF5</a> <br> - <a href="RM_H5Front.html">HDF5 Reference Manual</a> <br> - <a href="http://hdf.ncsa.uiuc.edu/HDF5/doc/UG/index.html">HDF5 User's Guide for Release 1.6</a> <br> - <!-- - <a href="Glossary.html">Glossary</a><br> - --> -</td> -<td valign=top align=right> - And in this document, the - <a href="H5.user.html"><strong>HDF5 User's Guide from Release 1.4.5:</strong></a> - <br> - <a href="Files.html">Files</a> - <a href="Datasets.html">Datasets</a> - <a href="Datatypes.html">Datatypes</a> - <a href="Dataspaces.html">Dataspaces</a> - <a href="Groups.html">Groups</a> - <br> - <a href="References.html">References</a> - <a href="Attributes.html">Attributes</a> - <a href="Properties.html">Property Lists</a> - <a href="Errors.html">Error Handling</a> - <br> - <a href="Filters.html">Filters</a> - <a href="Caching.html">Caching</a> - <a href="Chunking.html">Chunking</a> - <a href="MountingFiles.html">Mounting Files</a> - <br> - <a href="Performance.html">Performance</a> - <a href="Debugging.html">Debugging</a> - <a href="Environment.html">Environment</a> - <a href="ddl.html">DDL</a> -</td></tr> -</table> -</center> -<hr> -<!-- #EndLibraryItem --><h1>Mounting Files</h1> - - <h2>Purpose</h2> - - <p>This document contrasts two methods for mounting an hdf5 file - on another hdf5 file: the case where the relationship between - files is a tree and the case where it's a graph. The tree case - simplifies current working group functions and allows symbolic - links to point into ancestor files whereas the graph case is - more consistent with the organization of groups within a - particular file. - - <h2>Definitions</h2> - - <p>If file <code>child</code> is mounted on file - <code>parent</code> at group <code>/mnt</code> in - <code>parent</code> then the contents of the root group of - <code>child</code> will appear in the group <code>/mnt</code> of - <code>parent</code>. The group <code>/mnt</code> is called the - <em>mount point</em> of the child in the parent. - - <h2>Common Features</h2> - - <p>These features are common to both mounting schemes. - - <ul> - <li>The previous contents of <code>/mnt</code> in - <code>parent</code> is temporarily hidden. If objects in that - group had names from other groups then the objects will still - be visible by those other names. - - <li>The mount point is actually an OID (not a name) so if there - are other names besides <code>/mnt</code> for that group then - the root group of the child will be visible in all those - names. - - <li>At most one file can be mounted per mount point but a parent - can have any number of mounted children. - - <li>Name lookups will entail a search through the mount table at - each stage of the lookup. The search will be O(log - <em>N</em>) where <em>N</em> is the number of children mounted - on that file. - - <li>Files open for read-only can be mounted on other files that - are open for read-only. Mounting a file in no way changes the - contents of the file. - - <li>Mounting a child may hide mount points that exist below the - child's mount point, but it does not otherwise affect mounted - files. - - <li>Hard links cannot cross file boundaries. An object cannot - be moved or renamed with <code>H5Gmove()</code> in such a way - that the new location would be in a different file than the - original location. - - <li>The child can be accessed in a manner different from the - parent. For instance, a read-write child in a read-only - parent, a parallel child in a serial parent, <em>etc</em>. - - <li>If some object in the child is open and the child is - unmounted and/or closed, the object will remain open and - accessible until explicitly closed. As in the mountless case, - the underlying UNIX file will be held open until all member - objects are closed. - - <li>Current working groups that point into a child will remain - open and usable even after the child has been unmounted and/or - closed. - - <li>Datasets that share a committed datatype must reside in the - same file as the datatype. - - </ul> - - <h2>Contrasting Features</h2> - - <center> - <table border width="90%"> - <tr> - <th width="50%">Tree</th> - <th width="50%">Graph</th> - </tr> - - <tr valign=top> - <td>The set of mount-related files makes a tree.</td> - <td>The set of mount-related files makes a directed - graph.</td> - </tr> - - <tr valign=top> - <td>A file can be mounted at only one mount point.</td> - <td>A file can be mounted at any number of mount points.</td> - </tr> - - <tr valign=top> - <td>Symbolic links in the child that have a link value which - is an absolute name can be interpreted with respect to the - root group of either the child or the root of the mount - tree, a property which is determined when the child is - mounted.</td> - <td>Symbolic links in the child that have a link value which - is an absolute name are interpreted with respect to the - root group of the child.</td> - </tr> - - <tr valign=top> - <td>Closing a child causes it to be unmounted from the - parent.</td> - <td>Closing a child has no effect on its relationship with - the parent. One can continue to access the child contents - through the parent.</td> - </tr> - - <tr valign=top> - <td>Closing the parent recursively unmounts and closes all - mounted children.</td> - <td>Closing the parent unmounts all children but - does not close them or unmount their children.</td> - </tr> - - <tr valign=top> - <td>The current working group functions - <code>H5Gset()</code>, <code>H5Gpush()</code>, and - <code>H5Gpop()</code> operate on the root of the mount - tree.</td> - <td>The current working group functions operate on the file - specified by their first argument.</td> - </tr> - - <tr valign=top> - <td>Absolute name lookups (like for <code>H5Dopen()</code>) - are always performed with respect to the root of the mount - tree.</td> - <td>Absolute name lookups are performed with respect to the - file specified by the first argument.</td> - </tr> - - <tr valign=top> - <td>Relative name lookups (like for <code>H5Dopen()</code>) - are always performed with respect to the specified group - or the current working group of the root of the mount - tree.</td> - <td>Relative name lookups are always performed with respect - to the specified group or the current working group of the - file specified by the first argument.</td> - </tr> - - <tr valign=top> - <td>Mounting a child temporarily hides the current working - group stack for that child</td> - <td>Mounting a child has no effect on its current working - group stack.</td> - </tr> - - <tr valign=top> - <td>Calling <code>H5Fflush()</code> will flush all files of - the mount tree regardless of which file is specified as - the argument.</td> - <td>Calling <code>H5Fflush()</code> will flush only the - specified file.</td> - </tr> - - - </table> - </center> - - - <h2>Functions</h2> - - <dl> - <dt><code>herr_t H5Fmount(hid_t <em>loc</em>, const char - *<em>name</em>, hid_t <em>child</em>, hid_t - <em>plist</em>)</code> - <dd>The file <em>child</em> is mounted at the specified location - in the parent. The <em>loc</em> and <em>name</em> specify the - mount point, a group in the parent. The <em>plist</em> - argument is an optional mount property list. The call will - fail if some file is already mounted on the specified group. - - <table border> - <tr> - <th width="50%">Tree</th> - <th width="50%">Graph</th> - </tr> - <tr valign=top> - <td>The call will fail if the child is already mounted - elsewhere.</td> - <td>A child can be mounted at numerous mount points.</td> - </tr> - <tr valign=top> - <td>The call will fail if the child is an ancestor of the - parent.</td> - <td>The mount graph is allowed to have cycles.</td> - </tr> - <tr valign=top> - <td>Subsequently closing the child will cause it to be - unmounted from the parent.</td> - <td>Closing the child has no effect on its mount - relationship with the parent.</td> - </tr> - </table> - - <br><br> - <dt><code>herr_t H5Funmount(hid_t <em>loc</em>, const char - *<em>name</em>)</code> - <dd>Any file mounted at the group specified by <em>loc</em> and - <em>name</em> is unmounted. The child is not closed. This - function fails if no child is mounted at the specified point. - - <br><br> - <dt><code>hid_t H5Pcreate(H5P_MOUNT)</code> - <dd>Creates and returns a new mount property list initialized - with default values. - - <br><br> - <dt><code>herr_t H5Pset_symlink_locality(hid_t <em>plist</em>, - H5G_symlink_t <em>locality</em>)</code> - <dt><code>herr_t H5Pget_symlink_locality(hid_t <em>plist</em>, - H5G_symlink_t *<em>locality</em>)</code> - <dd>These functions exist only for the tree scheme. They set or - query the property that determines whether symbolic links with - absolute name value in the child are looked up with respect to - the child or to the mount root. The possible values are - <code>H5G_SYMLINK_LOCAL</code> or - <code>H5G_SYMLINK_GLOBAL</code> (the default). - - <br><br> - <dt><code>hid_t H5Freopen(hid_t <em>file</em>)</code> - <dd>A file handle is reopened, creating an additional file - handle. The new file handle refers to the same file but has an - empty current working group stack. - - <table border> - <tr> - <th width="50%">Tree</th> - <th width="50%">Graph</th> - </tr> - <tr valign=top> - <td>The new handle is not mounted but the old handle - continues to be mounted.</td> - <td>The new handle is mounted at the same location(s) as - the original handle.</td> - </tr> - </table> - </dl> - - <h2>Example</h2> - - <p>A file <code>eos.h5</code> contains data which is constant for - all problems. The output of a particular physics application is - dumped into <code>data1.h5</code> and <code>data2.h5</code> and - the physics expects various constants from <code>eos.h5</code> - in the <code>eos</code> group of the two data files. Instead of - copying the contents of <code>eos.h5</code> into every physics - output file we simply mount <code>eos.h5</code> as a read-only - child of <code>data1.h5</code> and <code>data2.h5</code>. - - <center> - <table border width="90%"> - <tr><td><h3>Tree</h3><code><pre> -/* Create data1.h5 */ -data1 = H5Fcreate("data1.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); -H5Gclose(H5Gcreate(data1, "/eos", 0)); -H5Gset_comment(data1, "/eos", "EOS mount point"); - -/* Create data2.h5 */ -data2 = H5Fcreate("data2.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); -H5Gclose(H5Gcreate(data2, "/eos", 0)); -H5Gset_comment(data2, "/eos", "EOS mount point"); - -/* Open eos.h5 and mount it in both files */ -eos1 = H5Fopen("eos.h5", H5F_ACC_RDONLY, H5P_DEFAULT); -H5Fmount(data1, "/eos", eos1, H5P_DEFAULT); -eos2 = H5Freopen(eos1); -H5Fmount(data2, "/eos", eos2, H5P_DEFAULT); - - ... physics output ... - -H5Fclose(data1); -H5Fclose(data2); - </pre></code></td></tr> - <tr><td><h3>Graph</h3><code><pre> -/* Create data1.h5 */ -data1 = H5Fcreate("data1.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); -H5Gclose(H5Gcreate(data1, "/eos", 0)); -H5Gset_comment(data1, "/eos", "EOS mount point"); - -/* Create data2.h5 */ -data2 = H5Fcreate("data2.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); -H5Gclose(H5Gcreate(data2, "/eos", 0)); -H5Gset_comment(data2, "/eos", "EOS mount point"); - -/* Open eos.h5 and mount it in both files */ -eos = H5Fopen("eos.h5", H5F_ACC_RDONLY, H5P_DEFAULT); -H5Fmount(data1, "/eos", eos, H5P_DEFAULT); -H5Fmount(data2, "/eos", eos, H5P_DEFAULT); -H5Fclose(eos); - - ... physics output ... - -H5Fclose(data1); -H5Fclose(data2); - </pre></code></td></tr> - </table> - </center> - - -<!-- #BeginLibraryItem "/ed_libs/NavBar_UG.lbi" --><hr> -<center> -<table border=0 width=98%> -<tr><td valign=top align=left> - <a href="index.html">HDF5 documents and links</a> <br> - <a href="H5.intro.html">Introduction to HDF5</a> <br> - <a href="RM_H5Front.html">HDF5 Reference Manual</a> <br> - <a href="http://hdf.ncsa.uiuc.edu/HDF5/doc/UG/index.html">HDF5 User's Guide for Release 1.6</a> <br> - <!-- - <a href="Glossary.html">Glossary</a><br> - --> -</td> -<td valign=top align=right> - And in this document, the - <a href="H5.user.html"><strong>HDF5 User's Guide from Release 1.4.5:</strong></a> - <br> - <a href="Files.html">Files</a> - <a href="Datasets.html">Datasets</a> - <a href="Datatypes.html">Datatypes</a> - <a href="Dataspaces.html">Dataspaces</a> - <a href="Groups.html">Groups</a> - <br> - <a href="References.html">References</a> - <a href="Attributes.html">Attributes</a> - <a href="Properties.html">Property Lists</a> - <a href="Errors.html">Error Handling</a> - <br> - <a href="Filters.html">Filters</a> - <a href="Caching.html">Caching</a> - <a href="Chunking.html">Chunking</a> - <a href="MountingFiles.html">Mounting Files</a> - <br> - <a href="Performance.html">Performance</a> - <a href="Debugging.html">Debugging</a> - <a href="Environment.html">Environment</a> - <a href="ddl.html">DDL</a> -</td></tr> -</table> -</center> -<hr> -<!-- #EndLibraryItem --><!-- #BeginLibraryItem "/ed_libs/Footer.lbi" --><address> -<a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a> -<br> -Describes HDF5 Release 1.4.5, February 2003 -</address><!-- #EndLibraryItem --><!-- Created: Spring 1999 --> -<!-- hhmts start --> -Last modified: 14 October 1999 -<!-- hhmts end --> - -</body> -</html> |