Baseline
Your reference cases run on the legacy code and outputs are captured as the ground truth.
Fortran still runs climate models, reactor simulations, flight analysis and decades of validated engineering work. Los Alamos researchers warned in 2023 that staffing Fortran projects with top-rate computer scientists is becoming unlikely. The code isn't the risk. The shrinking pool of people who can touch it is.
Modernize Software restructures legacy Fortran or migrates it to C++ and other modern languages with DMS, our symbolic AI and enhanced compiler technology, with numerical behaviour verified along the way.
Trusted By
| Path | What it means |
|---|---|
| Restructure the Fortran | Fixed-form Fortran 77 converts to modern free-form style: COMMON blocks become modules, computed and arithmetic GOTOs become structured control flow, implicit typing becomes explicit. Your scientists keep their language, minus the 1977. |
| Migrate to C++ | The full codebase translates to maintainable C++, opening the door to mainstream hiring, modern tooling and integration with current platforms. Java and C# targets are available where they fit the environment. |
| Mix the two | Hot numerical kernels stay in Fortran while surrounding orchestration migrates. The assessment maps which parts belong where. |
Shared-memory tricks that made sense on 1970s machines are analysed and converted to explicit, typed data structures (using C++ structs and unions) without changing behaviour.
Arithmetic IFs and GOTO webs restructure into readable loops and conditionals your next hire can follow.
Precision, evaluation order and library differences are tracked explicitly, and results are compared against baseline runs on your own cases.
DMS front ends cover Fortran 77 through Fortran 95, and the machinery is built for codebases in the millions of lines.
Your reference cases run on the legacy code and outputs are captured as the ground truth.
Restructuring or translation runs as automated, deterministic rules across the codebase.
The same cases run on the new code. Differences surface immediately and trace back to a specific rule.
Your domain experts review the comparison evidence, and cutover happens on proof.
General questions
Leave it alone while you can still staff it and still change it safely. The trigger is usually people, not code: when the engineers who understand the program are retiring and nobody new will touch fixed-form Fortran 77, the physics is at risk even though the program still runs.
Restructuring to modern free-form Fortran keeps your scientists in the language they think in and removes the 1977 constraints. Migrating to C++ opens up mainstream hiring, modern tooling and integration with current platforms. Many estates end up mixed, and the assessment maps which parts belong where.
Precision, evaluation order and library differences are tracked explicitly rather than assumed. Your reference cases run on the legacy code first and those outputs become the ground truth, then the same cases run on the new code and every difference traces back to a specific rule.
Yes. DMS front ends cover Fortran 77 through Fortran 95, including fixed-form source, COMMON blocks, EQUIVALENCE, computed and arithmetic GOTOs and implicit typing.
f2c-style tools transliterate: the output compiles but keeps the original shape, so a GOTO web stays a GOTO web and COMMON blocks become global pointer soup. DMS restructures at the architecture level into typed data structures and structured control flow, which is the part that makes the result maintainable.
Build files, compiler flags and library calls are inventoried in the assessment. Numerical library calls map to equivalents in the target environment, and anything without a clean equivalent is flagged before work starts rather than discovered late.
No. Rules are tuned while your team keeps working, and the final conversion runs as one automated pass on a fresh snapshot, so changes made during the project come across.
Yes, and it is a common choice. Hot numerical kernels can stay in Fortran while the surrounding orchestration migrates. The assessment maps the boundary and the interfaces between the two.
No. Transformation is rule-driven and deterministic through DMS using symbolic AI, which is what lets a difference in results trace back to a specific rule. Gen AI is used around the edges, for documentation and comprehension of undocumented code.
Organizations whose Fortran carries validated science or engineering: national labs, defence programs, aerospace, energy, weather and climate groups, and engineering software vendors with decades of numerical code behind their products.
Book a free assessment of your Fortran estate and get a modernization map.
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