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--- public:hdf5 [2010-09-14 07:30] – alexov
+++ public:hdf5 [2011-03-09 11:51] – Lars Bahren
@@ Line 1: / Line 1: @@
-HDF5 File Format Meeting
+====== HDF5 File Format Meeting ======
-September 9-10, 2010
+Location & Date:
-University of Amsterdam, The Netherlands
+    * University of Amsterdam, The Netherlands
+    * September 9-10, 2010
+Overview:
+    * Quincey Koziol from the HDF5 Group visited the LOFAR crew at the UvA on Thursday-Friday (Sept. 9-10th).  The agenda is listed below.  We gave Quincey an overview of LOFAR along with an introduction to the LOFAR data format/structures from the Interface Control Documents (ICDs).  All presentations are attached below. Quincey's HDF5 presentations can also be found below.
 Participants:
-HDF5 Group Member - Quincey Koziol
+   * HDF5 Group Member - Quincey Koziol
-Attendees - Anastasia Alexov, Ken Anderson, John Swinbank, Lars Baehren, Micheal Wise, Adriaan Renting, Ger van Diepen.
+   * Attendees - Anastasia Alexov, Ken Anderson, John Swinbank, Lars Baehren, Micheal Wise, Adriaan Renting, Ger van Diepen, Tom Bennett (South Africa via EVO)
-Agenda
+==== Agenda ====
-  *
+Thursday 10AM-lunch:
+   * LOFAR Overview (15-30 mins) - Swinbank, {{Swinbank-HDF5-LOFAR.pdf|An Introduction to LOFAR}}
+   * LOFAR Image cubes (15-30 mins) - Anderson, {{LOFAR_HDF5_SkyImage.ppt|LOFAR Sky Image Cubes}}
+   * (coffee break @11AM)
+   * LOFAR Beam-formed data (15-30 mins) -  Alexov, {{LOFAR-HDF5_BFoverview_20100909.ppt|LOFAR Beam-Formed Data & Pipeline Overview}}
+   * LOFAR Coordinates (15-30 mins) -  Baehren, {{2010-09-09-DAL.pdf|The Data Access Library ([[engineering:software:tools:DAL]])}}
+   *(lunch)
+Thursday 2PM-5PM:
+   * HDF5 talk/tutorial (60 min)  -  Quincey Koziol
+   * Discussion on questions/concerns listed below  - All
+Friday 10AM-lunch:
+   * Performance questions (15-30 mins) - van Diepen, {{hdf5-casacore.ppt|HDF5 and casacore}}
+   * Open discussion on performance
+   * (coffee break @11AM)
+   * HDF5/LOFAR-related questions - All
+   * (lunch)
+Friday 2PM-5PM:
+   * Open discussion - All
+==== HDF5 Presentations ====
+    * {{HDF5_Introduction1_Model.ppt|Introduction to HDF5}}
+    * {{HDF5_Introduction2_Format.ppt|Introduction to HDF5 - Session Two - Data Model Comparison; HDF5 File Format}}
+    * {{HDF5_Introduction3_Software.ppt|Introduction to HDF5 - Session Three - HDF5 Software Overview}}
+    * {{HDF5_Introduction4_Java.ppt|Introduction to HDF5 - Session Four - Java Products}}
+    * {{HDF5_DataValuesAreKey.ppt|Introduction to HDF5 - Session Five - Reading & Writing Raw Data Values}}
+    * {{HDF5_Introduction-Datatypes.ppt|Introduction to HDF5 - Session Seven - Datatypes}}
+    * {{HDF5_Introduction-IOPerformance.ppt|Introduction to HDF5 - High Performance I/O}}
+    * {{HDF5_Introduction-Math.ppt|Introduction to HDF5 - Introduction to Mathematical Concepts}}
+    * {{HDF5_Introduction-StorageOptions.ppt|Data Storage and I/O in HDF5}}
+    * {{HDF5Update.ppt|HDF5 Update}}
+==== QUESTION/TOPIC for DISCUSSION: ====
+   * performance benchmarks
+   * access patterns
+   * intelligent filtering and slicing
+   * efficient data storage / chunking
+   * parallel I/O
+   * distributed storage
+   * tools which exist for HDF5 (other than HDFView, h5py, pytables)
+==== CONCERNS: ====
+    * Speed when using smallish hyperslabs
+    * Robustness. E.g. What happens if a system crashes after writing some hours of data? What are the chances that all data are lost? What impact has robustness on performance?
+    * The future of the C++ interface.
+    * Is HDF5 always backward compatible? I.e. can a file created with HDF5 1.8 always be read with newer versions, even a hypothetical version 2.1 (AFAIK HDF5 1.8 is not backward compatible with 1.6). The same for building the software.
+    * Is it more efficient to store data in:
+     - One table per subband (N x 1-dimensional tables in one Group)
+     - One table for all subbands (1 x N-dimensional table in one Group)
+     - 1 Array per Subband (N x 1-dimensional array in one Group)
+     - 1 Array for all Subbands (1 x N-dimensional array in one Group)
+=== LOFAR ICD (Interface Control Documents): ===
+LOFAR Interface Control Documents (ICDs): [[http://usg.lofar.org/wiki/doku.php?id=documents:lofar_data_products]]