Introduction
The application talks from Boeing and NASA ICASE had a similar message. 
Large-scale computation for aircraft design is going to gain in importance but the 
challenges are not primarily the core differential equation solvers. Work on these is still 
important, as meshes of increasing complexity will be needed for future simulations. 
However the most critical issues are integration of simulation more effectively into the 
full design through production cycle. Grid generation speed, multi-disciplinary 
optimization, linkage of computation and experiment (wind tunnel), reliable error 
estimates, predictable turn-around and technologies to link engineers around the country 
were some of the systems issues discussed. The software talks from Alan Carle and 
Geoffrey Fox correspondingly stressed the approaches to these systems issues. They 
discussed technologies to support computational grids and the integration of commodity 
information services into high performance systems. The complexity of aircraft design 
imply that large scale distributed systems are important even if an individual 
computational component may be implemented a single high performance system or a 
relatively closely coupled cluster.

Salas You have
Cosner Due Monday

Software Discussion
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. Carle 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. Each approach has 
clear positive and negative features and any successful programming environment must 
combine many of these together. Any good approach is likely to need performance 
estimation, whole-program compilation, new approaches to compilation for scripted and 
visual environments, run-time compilation, libraries and programming support tools. 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.