Further Links:

• General Resource including all workshops and papers
• Presentation giving more detail on overall issues in HTML or Powerpoint
• The recent Java98 Conference (Palo Alto Feb 28--Mar1 98) including online papers and Photos
• Index of Java Grande Resource
• Further Details of Parallel and Distributed Computing Working Group
• Further Details of Numerics Working Group

What is Java Grande?

This is use of Java for:

• High Performance Network Computing
• Scientific and Engineering Computation
• (Distributed) Modeling and Simulation
• Parallel and Distributed Computing
• Data Intensive Computing
• Communication and Computing Intensive Commercial and Academic Applications
• HPCC
• Computational Grids ........

What is Goal of Java Grande Forum?

• Java has potential to be a better environment for "Grande application development" than any previous languages such as Fortran and C++
• The Forum Goal is to develop community consensus and recommendations for either changes to Java or establishment of standards (frameworks) for "Grande" libraries and services
• These Language changes or frameworks are designed to realize "best ever Grande programming environment"

Summary of Issues

• floating point issues
• exact bits
• rounding
• looseNumerics as discussed by Gosling
• exception flags
• exception traps
• NaNs, Infinities
• interval arithmetic
• extended precision
• complex numbers
• operator overloading
• templates (inlining, parameterized class types)
• arrays
• multidimensional (continguous) storage
• long integer indices
• standard classes (e.g. FortranArray3D)
• subarrays without copying
• resizing and composing of arrays
• array expressions (: notation of f90, matlab)
• aliasing
• Java numerical library interfaces (APIs)
• standard vector, matrix classes (e.g. SymmetricPackedDouble )(?)
• numeric (programming) exceptions (e.g. nonconforming arrays)
• Java libraries
• numerics
• MPI
• applcation-specific
• interfaces to legacy and native methods
• Lapack, BLAS, etc.
• standardized schemes for f77 bindings
• standard APIs for numeric classes (e.g. FortranArray3D)
• Tool interfaces
• monitors
• debuggers
• visualizations
• JVM and runtime issues
• Garbage Collection, threads
• JVM opcode extensions
• Java compiler optimizations
• JIT optimizations
• Inhibitors of compiler optimizations include:
• Memory Hierarchy (fpu/register/cache/main/disk)
• Interaction with Garbage Collection
• Thread memory model
• Weak consistency of shared variables
• Implicit shared variables
• Exception handling
• FP no intermediate results rules
• Scalability issues:
• The VM itself
• Thread creation, destruction and synchronization; Non-queued notifies

Subjects of top importance:

• RMI
• VM Specification and Implementation
• High-Level parallel, distributed models, and Libraries (SPMD, Active Objects, MIMD, etc. )
• Interfaces to other HPC Services (e.g. Meta-computing)
• Components architectures for scientific Computing
• Benchmarking

1. RMI and VM

2. High-Level Lib. and Interfaces to HPC Services

3. Components

while Benchmarking is pervasive to all areas

Some details on the two most important topics:

RMI Details:

• Data serialization / Serialization supports, access, and openness
• Allow the writting of specific algorithms for (un)marshalling, and the use of specific transport mechanisms.
• Invocations efficiency
• Different transport mechanisms
• Multicast actual implementation, and openness of the implementation
• Do we need asynchronous calls within RMI ?
• Is the single inheritance a limitation to RMI? and is there a way around it?

• Fast synchronization Mechanisms
• Scalability of Threads
• Multi-programming (and Multi-user ?) VM
• Awkward memory model for thread (simplification) (?)
• class unloading of VM (for long living VM)
• Meta-object (extension to reflection support) (?)
• Robustness of VM (long living)