Given by Geoffrey C. Fox at AirFrame Simulation Panel ARPA Sys.Env. Meeting Washington on 10-11 November 97. Foils prepared 1 dec 97
Outside Index
Summary of Material
Application talks by Manny Salas and Ray Cosner were in counterpoint to two software talks
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A computational grid is a large-scale high performance distributed computing system that presents new challenges from the heterogeneity of the nodes and the variable and sometimes poor performance of network latency and bandwidth. |
Application support should include both programming the typically data parallel simulation modules and the composition of modules to build complete processing systems. |
So the challenges are supporting fine grain concurrency within a single processor, data parallelism within a tightly coupled system and dataflow or other compositional model between nodes of the grid. |
Kennedy's talk reviewed the available technologies: auto-parallelism, explicit communication, distributed shared memory, data parallel languages, task or module parallelism, libraries typically supporting SPMD programming, programming tools, resource management, latency tolerance and run-time compilation.
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This presentation by Fox stressed that there were important systems engineering advantages in building computational grid support on "commodity technologies" such as CORBA and the Web. |
This allowed one to exploit database, collaboration and the natural software integration capabilities of these impressive commercial systems designed for pervasive information systems such as worldwide commerce and corporate enterprise Intranets. |
There are some critical research issues in how best to incorporate high performance into these systems without losing the power and flexibility of the commodity approach. |
Outside Index Summary of Material
Geoffrey Fox |
Syracuse University |
NPAC |
111 College Place Syracuse NY 13244 4100 |
3154432163 |
Applications are metaproblems with a mix of module and data parallelism |
Modules are decomposed into parts (data parallelism) and composed hierarchically into full applications.They can be the
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Modules are "natural" message-parallel components of problem and tend to have less stringent latency and bandwidth requirements than those needed to link data-parallel components
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Assume that primary goal of computational grid is to add to existing parallel computing environments, a higher level supporting module parallelism
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High end (today) to high end(tomorrow)
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High end(today) to low end(tomorrow)
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Low end(today) to low end(tomorrow)
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Low end(today) to very low end (tomorrow)
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The new application(s) we can't predict |
1997 |
2007 |
The transportation system was built using lessons from and feed up/down from Sports cars, Cadillacs, Model T's, Ford Escorts etc. |
Computational Grid will be shaped by and shape all 5 classes of applications on previous foil
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A highish end computational grid will in some sense (to be disagreed on) be influenced by and influence the "Web" which is here defined as "mass-market"/business IntraNet (low to low) use of Internet/distributed Information Systems |
1:User View: Interoperable Web Interface accessing services through Java Compute Services Framework |
2:Network of Java Servers provide distributed services with databases, compute engines, collaboratories, object brokers, instruments
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Back end "Number Crunchers" linked either by communication at level 2 (slowish but easy) or at level 3 (high performance but more work) |
Compute processes linked either to servers or together by MPI if parallel |
Java Servers |
This metacomputing model can be combined with emerging Web Collaboration, Object broker and database capabilities to support multidisciplinary applications and computational steering |
Simulation |
Basic Display |
Image Filter |
is another |
module |
Output Display after Filter |
Runs as a |
parallel |
module |
using |
Java Server |
host |
Systems such as Habanero or TANGO supports client side electronic societies of people, instruments and their applications. |
A network of Java Servers manage sessions and interfaces them to the world wide Server Infrastructure that underlies emerging model of Commodity applications |
In CORBA, Web Collaboration systems become a facility to support sharing and replication of objects. |
Command and Control or more generally distributed (tactical) real-time decision support -- decision makers and gatherers of information |
Forums and Chattering on the Web -- the world! |
Education -- teachers and students (and administrators) |
(Tele)medicine -- Doctors (primary and specialist referrals), Nurses, Patients and administrators |
Business Enterprise (strategic) Support as in Lotus Notes -- Employees of Business including especially managers |
Multidisciplinary Applications including Collaborative design -- teams of multi organization engineers |
Computational Steering -- one or more computational scientist and visualization device |
Systems such as TANGO link people and shared applications such as chat board, audio video conferencing, visualizations, shared white board, common AUTOCAD design and related tools |
CFD |
TANGO Server |
Database |
Object Broker |
MPP |
Structures |
MPP |
Engineer |
+ core |
services |
Visualization e.g.CAVE |
Shared AutoCAD |
Engineer |
+ core |
services |
This combines TANGO for collaboration with WebFlow to link server side applications |
If necessary WebFlow would support high performance inter-module communication at the backend but it would always implement control and this allows TANGO integration with server side computation
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WebFlow communication model is a dynamic dataflow |
Of course other server side compute models are possible and in general need (web-linked) data bases, file systems, object brokers etc., |
WebFlow supports dataflow model where user must supply routines to process input of data that drives module and output of data for other modules |
TANGO supports shared state and user supplies routines that read or write either
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Can be done for applications like AUTOCAD as vendor supplies necessary API |
CFD |
Structures |