May 05 2009
Types of software: Proprietary software
Proprietary software is computer software which is the legal property of one party. The terms of use for other parties is defined by contracts or licensing agreements. These terms may include various privileges to share, alter, dissemble, and use the software and its code.
In the free software movement the term is used for software that may not be used, modified and distributed according to the definitions of free software or for which the source code is not available. Although free software usually indeed is legal property of some parties, the license agreements include at least these specific privileges.
Literal and legal meanings
Exclusive legal rights to software by a proprietor contradict the kinds of freedom which are essential for free software. However, even software which is not proprietary, for example public domain software and software under a permissive licence, does not comply with the definition of free software, if the source code of that software is not available. Proprietary software includes freeware and shareware.
The free software movement’s founder Richard Stallman sometimes uses the term “user-subjugating software” to describe proprietary software, while Eben Moglen sometimes talks of “unfree software”. In a Free Software Foundation article, software which differs from free software only in that it limits the freedom to non-profit uses, is “semi-free” and not “proprietary”. The term “non-free” is often used by Debian developers to describe any software whose licence does not comply with Debian Free Software Guidelines, and they use “proprietary software” specifically for non-free software that provides no source code. The Open Source Initiative prefers the term “closed source software”.
Software distributions considered as proprietary may in fact incorporate a “mixed source” model including both free and non-free software in the same distribution. Most if not all so-called proprietary UNIX distributions are mixed source software, bundling open source components like BIND, Sendmail, X Window System, DHCP, and others along with a purely proprietary kernel and system utilities.
For some free software, the same laws used by proprietary software are used to preserve the rights to use, copy and modify the software. This technique is called copyleft.
