1. 1/30/2003 Los Alamos National Laboratory1 A Migration Framework for Legacy Scientific Applications  Current tendency: monolithic architectures large, complex, tightly coupled implementations ad-hoc evolution over time  Downside? limited number of developers who can modify/extend embedded scientific knowledge accrued is trapped  Upside? rich and valuable science job security?

2. 1/30/2003 Los Alamos National Laboratory2  An architecture that expands the developer base  Retain the rich scientific content  Modular, component-based architecture to enable a large, but manageable feature set Desirable Features

3. 1/30/2003 Los Alamos National Laboratory3 Desirable Outcomes  A system architecture with industry standard form approachable by a large audience  Re-architect with an OO infrastructure to retain embedded science  Establish well-defined interfaces to support generalized input mechanisms multiple plug-able physics models generalized output mechanisms integration of independently developed packages

4. 1/30/2003 Los Alamos National Laboratory4 Tools and Methods  Use accepted software engineering practices Source code version control Configuration management Automated regression testing Multiple platform portability  Use standards as much as possible CORBA (components) Patterns (modules) Languages (objects) See Los Alamos National Laboratory, LA-UR 01-6629

5. 1/30/2003 Los Alamos National Laboratory5 Results to Date  Trust established with automated regression testing  Optimized CORBA IDL implementation success on several UNIX platforms based on dynamic libraries Linux Solaris HP/UX IRIX  Modules in multiple languages (on Linux) Fortran 90 C C++  Priority changes resulting in loss of interest and funding

6. 1/30/2003 Los Alamos National Laboratory6 Future Efforts and Approaches  Find interest and funding  Try CHASM (language glue) See http://acts.nersc.gov/presentations/Workshop2002/ slides/Rasmussen.pdf  Write IDL compiler for support