Desco -- a tool for education and control of discrete event systems The authors report on a software suite which has been developed to facilitate the manipulation of state automata and Petri nets for supervisor calculation (among other things). This suite of software tools includes a graphical automata/Petri net drawing tool, a commandline based automata/Petri net manipulation tool and a graphical visualization tool. The two first tools (jointly named Desco, for Discrete Event Systems COntroller), consisting of the N’gin (i.e. the mathematical manipulation engine) and the GUI (the graphical user interface) have been developed at the Control and Automation Laboratory at Chalmers University of Technology. The third tool is a general graph drawing software, GrapViz, from AT&T research, which is closely integrated with Desco