The results of all this entrepreneurial ferment are staggering: MIT alumni and faculty start more than 200 new companies every year, according to the MIT Venture Mentoring Service; as a group, they’ve founded thousands of companies ranging from huge, well-known firms such as Hewlett-Packard, Bose and Intel, to rising companies including A123 Systems, Zipcar and Dropbox. Collectively, these firms have created millions of jobs. They also generate about $2 trillion a year in revenues, according to a 2009 study.