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Science Data Access Architectures Mike Martin 11/30/06. Background Proposed to Ed to survey information system capabilities across NASA disciplines. Where are they now, where are they going?
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Science Data Access Architectures Mike Martin 11/30/06
Background • Proposed to Ed to survey information system capabilities across NASA disciplines. Where are they now, where are they going? • Especially interested in capabilities and tools that could answer “requirements” in MRO User Scenario Document by Ray Arvidson and Jim Murphy, something of a PDS “vision” statement. • First step, look at middleware architectures.
For several selected middleware architectures: • Describe how each scheme works. • Compare the different approaches to common problems. • Identify any exemplary or noteworthy features of the various schemes. • It quickly became apparent that there was a lot of excitement about Service Oriented Architecture (SOA) and “Web Services”. • Commoditize information and computer resources for autonomous consumption. • SOAP messages, WSDL service contracts and UDDI service registries.
Selected Systems include: • Open GIS Consortium’s Open Web Services (OWS), servers for digital maps, images and GIS data. • International Virtual Observatory Alliance (IVOA) registry and data access services for astrophysics data. • Planetary Data System’s implementation of Object Oriented Data Technology (PDS-OODT) for query, profile and product servers. • Earth Observing System Clearinghouse (ECHO) for a central catalog identifying earth science data and services.
Highlights: • OWS layered discovery model (GetCapabilites(), DescribeRecords(), GetRecords(); and harvesting capability • IVOA cone search, VOTable, summer studies. • “Web Services” orientation in ECHO and IVOA. • Lowlights: • No standard XML query language • Mixing service registry and catalog functions.
Conclusions: • OWS - Elegant architecture. Now someone needs to make it work, especially the catalog servers. • IVOA - Great architectural vision. Interesting data oriented service approach. Seems to have widespread community support. • PDS-OODT - Great job implementing product servers, now do profile servers at every node. IPDA efforts are adding support for VOTable and GetCapabilites features. • ECHO - Wide range of services exposed via API. Still seems immature, despite being on Version 8. Will central spatial database be a success?
Next steps • Get feedback from you folks and others at tahoe_mike@sbcglobal.net • Should other schemes be included (the Grid, Opendap)? • Other analysis/observations based on this information? • Is there hope for long term convergence (earth, space, planetary and astrophysics all using same service architectures)?