Panel: Revisiting Distributed Simulation and the Grid IEEE DS-RT 2005 Montreal Canada Oct. 11 2005 Geoffrey Fox Computer Science, Informatics, Physics Pervasive Technology Laboratories Indiana University Bloomington IN 47401 gcf@indiana.edu http://www.infomall.org

Major Changes in Grids over last year Tend to use term Grid not Grid computing due to importance of data deluge This change fine for distributed simulation as often wants to use substantial data (sensor streams) Web service base better established with all GGF work based on this and use by all major projects: GT4, OMII, EGEE, Asia Grids … Some disputes in detail such as WS-Man v. WSDM but important principles agreed by major industry players Key standards are in debate or changed/emerged during last year Essential features of WSDL and SOAP unchanged

Benefits from Grids Grids do not suggest new simulation paradigms but rather enables access to growing number of grid and web service enabled resources Access to the real time data deluge could lead to new simulation methods using data assimilation more extensively Could enable new simulation areas Provide supportable software base supplying all distributed system features not in RTI Inevitable interoperability of Grid infrastructure could lead to more competition in simulation infrastructure development area

Barriers to use of Grids One can build “mediation” interfaces between HLA and other simulation systems and the Grid However hard to fully exploit the Grid (e.g. use real-time data in microscopic simulation) as long as RTI and Grids use such different distributed system architectures As Grids and Web services still evolving (and might even “fail”/”change radically”) not trivial to justify major investment “Grid community” from HPCC not from distributed simulation community Grid of GiG not “same” as Grid of GGF/EGA/IBM

Alternatives to Grids? For next few years Grids and Web Services are likely to continue as dominant distributed simulation technologies Grids and web services are by my definition synergistic (Grids build on WS-*) and so use of WS is equivalent to use of Grids Does say there are more or less complex ways of using Grids Enhancing existing distributed simulation in “distributed part” likely to have low ROI unless use Grids Could wait 5 years to see next “distributed system revolution” but non WS/Grid systems will get less and less attractive

Why are Grids Important Grids are important for DoD because they essentially address DoD’s problem and have made major progress in the core infrastructure that DoD has identified rather qualitatively Grids are important to distributed simulation because they address all the distributed systems issues except simulation and in any sophisticated distributed simulation package, most of the software is not to do with simulation but rather the issues Grids address DoD and Distributed Simulation communities are too small to go it alone – they need to use technology that industry will support and enhance

Some ideas to Remember Grids replace previous sophisticated distributed object technologies because industry won’t support DO’s but will support services Grids are managed Services exchanging Messages Grid Services GS-* extend WS-* Web Service Specifications Web Service container replaces computer Service replaces process A stream is an ordered set of messages Service Internet replaces Internet: messages replace packets (Sub)Grids replace Libraries 7 out of 9 NCOW Core Enterprise Services CES directly from Grid Services; metadata, (part of) messaging, collaboration, and sensors need special attention RTI should be enhanced with agreed service interfaces and interoperable RTI-SOA