S is a statistical programming language developed to “to turn ideas into software, quickly and faithfully”. There were two different types of S language. The old S which was the first designed, offered an alternative and more interactive approach and the other was the New S which was published to introduce new features such as the transition from macros to functions and how functions can be passed to other functions (such as “apply”).
The modern implementation of S is R.
R is a language and environment for statistical computing and graphics. R can be considered as a different operation of S but much code written for S runs intact under R. It provides a wide variety of statistical and graphical techniques. One of R’s strengths is how easy it is to design and publish documentation.
R is available as Free Software under the terms of the Free Software Foundation’s GNU General Public License in source code form. Free and open source software is exactly what it sounds like; free and open source software. What does this mean? Free and open source software is provided free of charge, meaning that anyone can use it anytime they want for whatever means they need without having to pay any fees. According to the Free Software Foundation, “Nearly all open source software is free software. The two terms describe almost the same category of software, but they stand for views based on fundamentally different values.” Thus, the Open Source Initiative considers many free software licenses to also be open-source. There are a number of related terms and abbreviations for free and open source software (FOSS or F/OSS) or free/libre and open source software (FLOSS).