Technical University of Twente SIMulation (TUTSIM)
20-sim is the succesor of the modeling and simulation software Tutsim. Tutsim was developed at the University of Twente in the late 70's. The package was commercially available for UNIX and DOS based computers in the 80's until development stopped in the 90's.
In the meanwhile at the University of Twente a new program, 20-sim, was developed for Windows computers, which is now being commercially sold by the company Controllab Products B.V.. 20-sim is fully Tutsim compatible: especially Tutsim users will appreciate the submodel libraries of 20-sim, which contain all the standard Tutsim submodels ..... and many more. Modeling within 20-sim is very similar to the Tutsim approach.
Convince yourself by downloading the free demo version of 20-sim and you will find out that modeling has never been easier!