What is open source software?

Open source refers to software applications in which the code used to create the program is freely available to use, view, and modify. The software (and the code) can be freely distributed without paying a royalty. Some well known open-source projects are Linux (an operating system), Apache (a web server), and MySQL (a database server).

Open source has been very successful in areas where the developers of applications are also the users of the applications. The open-source projects mentioned above were all started by developers who needed tools to help them create software. These projects have now matured to the point that non-developers can easily use them as well. This phenomenon explains in part the slow adoption of open-source medical software. The vast majority of users (clinicians) are not software developers (or even so-called power users).