Free and open source software (FOSS) is not so easy to define and much harder to understand, thankfully Lego has come to the rescue with a well produced video that simply explains a complex subject.
A practical example of how open source software differs from proprietary software presented itself recently on the school library listserv around how book series are displayed in the catalogue.
The librarian thought, “Wouldn’t it be good if the OPAC could show the next book in a series”, a feature that was not available with their library system. Now, if you are using a proprietary system, your only course of actions is to contact the software vendor and ask for a new feature to be included. You are at the mercy of the software owner, they will decide what features are added and when. If they decide a feature is not to be added, there are no other alternatives.
With open source software it’s different; since you have access to the source code you are able to change the software yourself or engage someone else to do it for you. Even better, with open source software, you can share your new features with other users so that everyone benefits from your work.