Open Source Software Development
The default assumption in software engineering is that software is developed by a company as a proprietary product, i.e., the company owns the source code and sells (licenses for use of) binary executables. A user or customer who wants changes in the software has to back to the
company for these changes to be realized.
In the open source
model of software development, each user not only gets binaries, but also the complete source code of the system, the right to make changes to the code, and
to distribute the changed sources.