Scot Martin, Harvard University, HDF Guest Blogger HDF5 storage is really interesting. To me, its format has no fixed structure, but instead is based on introspection and discovery. Seems great to me; Mathematica has its origins first in artificial intelligence, so we ought to be able to do something here.  Approaching twenty-two years with Mathematica and almost a “Hello, World!” ability in C, I decided to jump right in. Enter The HDF Group's P/Invoke for my salvation. Here’s how we make use of it in Mathematica: LoadNETAssembly["HDF.PInvoke.dll"] Bang! Ready to go in Mathematica. Here’s a proof of concept for how it works: Module[ (* The three symbols should have initial values so that there is *) (* memory allocation when Mathematica interfaces with P/Invoke. *) {major=0,minor=0,revision=0,return}, CompoundExpression[ (* access...

Christian Hoene, Symonics GmbH; and Piotr Majdak, Acoustics Research Institute; HDF Guest Bloggers Spatial audio - 3D sound.  Back in the ‘70’s, “dummy head” microphones were used to create spatial audio recordings. With headphones, one was able to listen to those recordings and marvel at the impressive spatial distribution of sounds – just like in real life. [caption id="attachment_11132" align="aligncenter" width="624"] Displays the difference between listening to a real source and listening to realistic virtual sounds via headphones[/caption] Nowadays, we have a much better understanding of the human binaural perception and we can even simulate spatial audio signals with the help of computers.  Indeed, a modern virtual reality (VR) headset such as the Oculus Rift or Samsung Gear utilizes 3D audio to allow...

Mark Miller, Lawrence Livermore National Laboratory, Guest Blogger The HDF5 library has supported the I/O requirements of HPC codes at Lawrence Livermore National Labs (LLNL) since the late 90’s. In particular, HDF5 used in the Multiple Independent File (MIF) parallel I/O paradigm has supported LLNL code’s scalable I/O requirements and has recently been gainfully used at scales as large as 1,000,000 parallel tasks. What is the MIF Parallel I/O Paradigm? In the MIF paradigm, a computational object (an array, a mesh, etc.) is decomposed into pieces and distributed, perhaps unevenly, over parallel tasks. For I/O, the tasks are organized into groups and each group writes one file using round-robin exclusive access for the tasks in the group. Writes within groups are serialized but...

DOE has continued to partner with The HDF Group, supporting development of HDF5 through two generations of computing; sponsoring this development has benefited the entire HDF5 user community. Today, DOE supports current HDF5 R&D to ensure that the data challenges of third generation exascale computing ...

MuQun (Kent) Yang, The HDF Group

Many NASA HDF and HDF5 data products can be visualized via the Hyrax OPeNDAP server through Hyrax’s HDF4 and HDF5 handlers.  Now we’ve enhanced the HDF5 OPeNDAP handler so that SMAP level 1, level 3 and level 4 products can be displayed properly using popular visualization tools.

Organizations in both the public and private sectors use HDF to meet long term, mission-critical data management needs. For example, NASA’s Earth Observing System, the primary data repository for understanding global climate change, uses HDF.  Over the lifetime of the project, which began in 1999, NASA has stored 15 petabytes of satellite data in HDF which will be accessible by NASA data centers and NASA HDF end users for many years to come.

In a previous blog, we discussed the concept of using the Hyrax OPeNDAP web server to serve NASA HDF4 and HDF5 products.  Each year, The HDF Group has enhanced the HDF4 and HDF5 handlers that work within the Hyrax OPeNDAP framework to support all sorts of NASA HDF data products, making them interoperable with popular Earth Science tools such as NASA’s Panoply and UCAR’s IDV.  The Hyrax HDF4 and HDF5 handlers make data products display properly using popular visualization tools. 

Lindsay Powers, The HDF Group

The 2015 HDF workshop held during the ESIP Summer Meeting was a great success thanks to more than 40 participants throughout the four sessions.  The workshop was an excellent opportunity for us to interact with HDF community members to better understand their needs and introduce them to new technologies. You can view the slide presentations from the workshop here.

From my perspective, the highlight of the workshop was the Vendors and Tools Session where we heard from Ellen Johnson (Mathworks), Christine White (Esri), Brian Tisdale (NASA), and Gerd Heber (The HDF Group) talk about new, and improved applications of HDF technologies.  For example:  

Quincey Koziol, The HDF Group

“A supercomputer is a device for turning compute-bound problems into I/O-bound problems.” – Ken Batcher, Prof. Emeritus, Kent State University.

HDF5 began out of a collaboration between the National Center for Supercomputing Applications (NCSA) and the US Department of Energy’s Advanced Simulation and Computing Program (ASC), so high-performance computing (HPC) I/O has been in our focus from the very beginning.  As we are starting our 20th year of development on HDF5, HPC I/O continues to be a critical driver of new features.

Los Alamos National Laboratory is home to two of the world’s most powerful supercomputers, each capable of performing more than 1,000 trillion operations per second. Here, ASC is examining the effects of a one-megaton nuclear energy source detonated on the surface of an asteroid. Image from ASC at

The HDF5 development team has focused on three things when serving the HPC community: performance, freedom of choice and ease of use.