FreeDOS is open source software! It doesn’t cost anything to download and use FreeDOS. You can also share FreeDOS for others to enjoy! And you can view and edit our source code, because all FreeDOS programs are distributed under the GNU General Public License or a similar open source software license.
FreeDOS started as a small operating system idea in early 1994. FreeDOS continues today becuase FreeDOS is open source software. We try very hard to only include only programs that are open source software, and useful to many people.
Sometimes, we talk about proprietary or "closed source" DOS programs. For example, we may highlight popular DOS games or applications. This is not meant to promote proprietary software over open source software. Instead, we do this to show that any program that works on MS-DOS should also run on FreeDOS.
We also reach out to vendors who released popular DOS applications, to try to convince them to release those programs as open source. Where they cannot release source code, we ask them to at least release these programs as free (gratis) software, so everyone can use them. However, we cannot include these free-but-closed programs in FreeDOS.