Australian Virtual Observatory A distributed volume rendering grid service Gridbus 2003 June 7 Melbourne University David Barnes School of Physics, The University of Melbourne

Overview what is a virtual observatory? astronomy data cubes 101 volume rendering distributed data volume rendering turning it into a grid serviceturning it into a grid service future projects

Virtual observatories bring legacy astronomy archives on-line and ensure future project compliance describe data fully, and support a finite, well-chosen set of interoperability protocols visualisedevelop tools and interfaces to find, acquire, process and visualise data build national and international grids and embed the data, tools and interfaces in those grids

Astronomy data cubes 101 you may have only seen 2d astronomy images an increasing number of telescopes and simulations produce multi-dimensional data astronomy data cubes are 3d arrays of pixels (voxels) typically the axes might be latitude and longitude on the sky, and frequency of radiation lots of information!lots of information! Right ascension Declination Radio frequency

Volume rendering volume rendering3d data can be viewed in slices, or we can render lines of sight through the entire volume - this is volume rendering and may offer new insights to complex data collections

Distributed data volume rendering split large volume into smaller pieces share the pieces out to nodes of a Beowulf cluster on demand the nodes render their piece of data other nodes glue the pieces together to form the final image provides increased speed and ability to handle larger-than-memory volumes See Beeson, Barnes & Bourke, PASA, submitted

Distributed data volume rendering Rendering controlled by a remote client connected on a socket Joint project with AstroGrid (UK) to recast the software as a grid service for demonstration in July at a major astronomy conference in Sydney.Joint project with AstroGrid (UK) to recast the software as a grid service for demonstration in July at a major astronomy conference in Sydney.

Making a grid service Collaborating groups now include –Melbourne (Physics & Computer Science / SE) –AstroGrid (Cambridge, Leicester) –VPAC, APAC, CSIRO CMIS, …, as data centres and rendering clusters Lead is being set by Guy Rixon (Cambridge) who has designed the system and is managing the project plan day-to-day Why? –Saves you from fetching large data files –Enables use of distributed computing resources –Demonstrator of grid technologies for VOs

Structure PortalPortal provide an interface for the user to find and select data and to select a rendering cluster (80% complete) Data centreData centre service provides a registry of its data holdings and some tools to eg. extract sub-images (60%) Data centre runs a gsiftp server to provide authenticated access to the data (~100%) Cluster centreCluster centre service fetches the data, starts up a rendering tree, loads the data and opens up a port (90%) appletPortal provides an applet to connect to that port and control and display the rendering (25%)

Development environment Globus 2.4 for gsiftp servers Tomcat for portals and service wrappers Globus 3.0 alpha 4 for grid services deployed within Tomcat Sun J2SDK 1.4.1_03 Netscape 7.02 (Gecko/ ) All data and rendering centres are Linux Tested clients include Linux, Windows and Mac OS X

Release 0 - June One hard-coded compressed FITS image in place of final data selection result One hard-coded rendering cluster in place of final cluster selection result Rendering cluster retrieves image from data centre via HTTP, decompresses it, converts it to volume rendering input format and stores it locally Applet served from portal server, running in clients browser, successfully connects to rendering cluster and requests an image.

The future Jias GridFTP client code to be incorporated next week - render cluster service complete! Data registry and data centre grid service including selection to be ready in ~two weeks Display and control applet to be largely completed over next four weeks.

Beyond the demo… Review demonstration in August CSIRO ATNF group developing Java interface to legacy astronomy software –suitable long-term location of this project? Conversion of Beowulf-class rendering tree to genuine distributed grid service for the piecewise rendering? Integration with massive on-line parameterised databases?