Free and open-source software (FOSS) is software that is:
1. Free - which means it does not cost money to use or download it.
2. Open-source - which means that the code for the software is available for people to look at and can be changed or modified.
The timeline of FOSS begins in the early 1960s with the invention of Unix, which was one of the first operating systems to be released as FOSS. This was followed by the GNU Project in the 1980s, which aimed to create a complete FOSS operating system. The completion of this project then led to the development of the Linux kernel, which is the core of a majority of FOSS operating systems today.
In the late 1990s and early 2000s, the FOSS movement grew significantly due to the popularity of the Linux operating system and the development of a number of open-source applications. This included the development of the Firefox web browser, which was released in 2002, and the OpenOffice office suite, which was released in 2003. By this time, the FOSS movement had become a major force in the software industry.
Today, FOSS is an integral part of the software industry. There are thousands of open-source projects, ranging from operating systems to web browsers and office suites, as well as a variety of other applications. It is estimated that at least 28% of desktop software is based on FOSS, and FOSS is an important part of the software industry.