diff options
| -rw-r--r-- | doc/html/Chunking.html | 22 | ||||
| -rw-r--r-- | doc/html/Filters.html | 20 | ||||
| -rw-r--r-- | doc/html/Performance.html | 4 |
3 files changed, 40 insertions, 6 deletions
diff --git a/doc/html/Chunking.html b/doc/html/Chunking.html index f898f58..8fd363a 100644 --- a/doc/html/Chunking.html +++ b/doc/html/Chunking.html @@ -58,6 +58,7 @@ <li><a href="#S3">3. Cache Efficiency</a> <li><a href="#S4">4. Fragmentation</a> <li><a href="#S5">5. File Storage Overhead</a> + <li><a href="#S6">6. Chunk Compression</a> </ul> <h2><a name="S1">1. Introduction</a></h2> @@ -215,7 +216,22 @@ <code>H5Pset_istore_k()</code> (increasing the out degree actually increases file overhead while decreasing the number of nodes). - <hr> + + <h2><a name="S6">6. Chunk Compression</a></h2> + + <p>Dataset chunks can be compressed through the use of filters. + See the chapter “<a href="Filters.html">Filters in HDF5</a>.” + + <p>Reading and rewriting compressed chunked data can result in holes + in an HDF5 file. In time, enough such holes can increase the + file size enough to impair application or library performance + when working with that file. See + “<a href="Performance.html#Freespace">Freespace Management</a>” + in the chapter + “<a href="Performance.html">Performance Analysis and Issues</a>.” + + +<hr> <p><a name="fn1">Footnote 1:</a> Parallel versions of the library can access individual bytes of a chunk when the underlying file @@ -224,7 +240,6 @@ <p><a name="fn2">Footnote 2:</a> The raw data chunk cache was added before the second alpha release. - <hr> <center> <table border=0 width=98%> @@ -273,12 +288,13 @@ <!-- Created: Tue Oct 20 12:38:40 EDT 1998 --> <!-- hhmts start --> -Last modified: 16 February 2001 +Last modified: 2 August 2001 <!-- hhmts end --> <br> Describes HDF5 Release 1.5, Unreleased Development Branch + </body> </html> diff --git a/doc/html/Filters.html b/doc/html/Filters.html index e4efc5f..f292bfd 100644 --- a/doc/html/Filters.html +++ b/doc/html/Filters.html @@ -55,7 +55,8 @@ <h2>1. Introduction</h2> - <p>HDF5 allows chunked data to pass through user-defined filters + <p>HDF5 allows chunked data<sup><a href="#fn1">1</a></sup> + to pass through user-defined filters on the way to or from disk. The filters operate on chunks of an <code>H5D_CHUNKED</code> dataset can be arranged in a pipeline so output of one filter becomes the input of the next filter. @@ -507,6 +508,21 @@ H5Z: filter statistics accumulated over life of library: <hr> + + + <p><a name="fn1">Footnote 1:</a> Dataset chunks can be compressed + through the use of filters. Developers should be aware that + reading and rewriting compressed chunked data can result in holes + in an HDF5 file. In time, enough such holes can increase the + file size enough to impair application or library performance + when working with that file. See + “<a href="Performance.html#Freespace">Freespace Management</a>” + in the chapter + “<a href="Performance.html">Performance Analysis and Issues</a>.” + + + +<hr> <center> <table border=0 width=98%> <tr><td valign=top align=left> @@ -554,7 +570,7 @@ H5Z: filter statistics accumulated over life of library: <!-- Created: Fri Apr 17 13:39:35 EDT 1998 --> <!-- hhmts start --> -Last modified: 17 December 1999 +Last modified: 2 August 2001 <!-- hhmts end --> <br> diff --git a/doc/html/Performance.html b/doc/html/Performance.html index 36accbf..5486e57 100644 --- a/doc/html/Performance.html +++ b/doc/html/Performance.html @@ -63,7 +63,9 @@ <a href="Chunking.html">Dataset Chunking Issues</a> elsewhere in this <cite>User's Guide</cite>. + <a name="Freespace"> <h2>3. Freespace Management</h2> + </a> <p>HDF5 does not yet manage freespace as effectively as it might. While a file is opened, the library actively tracks and re-uses @@ -235,7 +237,7 @@ <!-- Created: Thu Oct 14 16:46:00 CDT 1999 --> <!-- hhmts start --> -Last modified: 11 July 2001 +Last modified: 2 August 2001 <!-- hhmts end --> <br> |