HDF5 File Format Meeting

Location & Date:

  • University of Amsterdam, The Netherlands
  • September 9-10, 2010


  • 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.


  • HDF5 Group Member - Quincey Koziol
  • Attendees - Anastasia Alexov, Ken Anderson, John Swinbank, Lars Baehren, Micheal Wise, Adriaan Renting, Ger van Diepen, Tom Bennett (South Africa via EVO)

Thursday 10AM-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 and casacore
  • Open discussion on performance
  • (coffee break @11AM)
  • HDF5/LOFAR-related questions - All
  • (lunch)

Friday 2PM-5PM:

  • Open discussion - All
  • 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)
  • 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:
  1. One table per subband (N x 1-dimensional tables in one Group)
  2. One table for all subbands (1 x N-dimensional table in one Group)
  3. 1 Array per Subband (N x 1-dimensional array in one Group)
  4. 1 Array for all Subbands (1 x N-dimensional array in one Group)

LOFAR ICD (Interface Control Documents):

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