About 25 years ago, Marv Klotz gave model engineers 128 calculators running under Microsoft DOS for conducting workshop, mathematical, and design calculations. Unfortunately, they are no longer available online. The calculators were written in C and were very difficult to update.
Now they are available for Mac, Linux and Windows 10+ and can be downloaded.
All 128 Calculators Marv created for Microsoft DOS have been successfully converted to Go and are available at https://github.com/dsbitor/MWKCalculators/. The code and full documentation (not available for the original code) are available for every calculator. The new code includes Go test cases for every calculator, which can be used for both basic testing and edge-case testing.
Enjoy!