Hermes
Hermes is a tool for making complex calculations and 2D plotting. It can handle and combine real functions, set of measured values, operations like derivations, integrations, fast Fourier transform, data modeling, etc... It has a general interface for data acquisition systems and can acquire data, make simple calculations on them and plot the result in real time. A data simulator and a Fourier synthesizer are included.
Hermes is used every day for physics teaching.
For the moment, all the user interface and its documentation are in French, even if all is ready for their translation (but time is not extendable...). The documentation may not be up to date everywhere, for Hermes is changing every day. You can get the most recent version of Hermes at http:\\gemeu.free.fr.