Free software, software libre, or libre software is computer software that gives users the freedom to run the software for any purpose as well as to study, change, and distribute the software and the adapted versions. The right to study and modify free software gives full access to its source code. For computer programs which are covered by copyright law this is achieved with a software license where the author grants users the aforementioned freedoms. Software which is not covered by copyright law, such as software in the public domain is free if the source code is in the public domain (or otherwise available without restrictions). Other legal and technical aspects such as software patents and Digital restrictions management can stop from exercising their rights, and thus prevent software from being free. Free software may be developed collaboratively by volunteer computer programmers or by corporations; as part of a commercial, for-profit activity or not.Free software is a matter of liberty, not price: users, individually or collectively, are free to do what they want with it – this includes the freedom to redistribute the software free of charge, or to sell it (or related services such as support or warranty) for profit. Free software thus differs from proprietary software (such as Microsoft Office, Google docs or iWork from Apple), which prevents users from studying, changing and sharing the software. Free software is also different from freeware, which is simply a category of freedom-restricting proprietary software which does not require payment for use. Proprietary software (including freeware) use restrictive software licences or EULAs and usually do not provide access to the source code. Users are thus prevented from changing the software, and this results in the user relying on corporations (such as Microsoft) to provide updates, help, and support. This situation is called vendor lock-in. Users often can't reverse engineer, modify, or redistribute proprietary software.The term ""free software"" was coined in 1985 by Richard Stallman when launching the GNU Project - a collaborative effort to create a freedom-respecting operating system - and the Free Software Foundation, or FSF. The FSF's Free Software Definition states that users of free software are ""free"" because they do not need to ask for permission to use the software.