Exercise 4

A detailed definition of open source software is presented at http://www.perens.com/OSD.html
Review this document in order to answer the following questions:

1. How does open source software differ from software in the public domain?
2. Can a program be distributed under both an open source license and a commercial license?
3. If anyone can modify and redistribute open source software, how can you know what version you're getting?
4. Can someone make a trivial modification to an open source program and then market the slightly modified program under a commercial license.