The Unix operating system was also developed on a cooperative basis by AT&T with the active support of many universities and research establishments. Many of the early Unix contributors were disappointed when AT&T began in the late 1970's and 1980's, to enforce their copyright terms over the use and distribution of Unix. This eventually resulted in the long and bitter legal battle between AT&T (and subsequently Novell who bought the Unix copyrights from AT&T in 1991) and the University of California at Berkeley. In a partial response to this problem of individual control of a public software development project, The Massachusetts Institute of Technology (MIT) in Cambridge, MA has, since 1984, supported Richard Stallman's efforts to launch a movement in the software development community to support the development of free software. This resulted in the establishment of The Free Software Foundation (the FSF), and its GNU project. The name GNU follows in an early Unix tradition of using recursive acronyms as program names, and stands for Gnu's Not Unix. The FSF continues to be head-quartered at MIT, and has enjoyed amazing success over the last decade with products like GNU C, GNU C++, Emacs, and many other products, many of which form substantial and key building blocks of the Linux operating system. Richard Stallman insists, with some justification, that Linux should correctly be known as a GNU system.
There are many other "free software" licenses that some of the code in Red Hat Linux has been licensed under. The most popular of these are the University of California at Berkeley BSD License whereby the copyright holder remains the registered owner but where no restrictions on further distribution are imposed on the user of the code.
Also coming from MIT, but not related to the FSF or the GPL, is the X Consortium, which is a Unix industry sponsored effort to build and maintain the X Window System. In turn, a group called the XFree86 Project has taken on the responsibility to port the X Window System to the Intel platform. We have included copies of each of these licenses in the appendix of this manual for your convenience. Linux is continuing to progress very rapidly because of the contributions of this world wide development effort, to which you and your company or school are encouraged to contribute.