The term “Open Source Software” (OSS) is used in a variety of contexts to refer to any (or a combination) of four (4) interrelated concepts: an OSS development model, OSS philosophies, OSS licensing regimes, and OSS business models. The four concepts taken together help define what is known as OSS.

 

Unlike traditional software business models, where distribution and licensing are for the purpose of creating a sustainable return on R&D investments through direct commercialization of the software, Open Source Software is commercialized through the sale of related services, hardware and solutions.

 

There are varying degrees of freedom adopted by the OSS community, but there is no single or unified OSS philosophy. In fact, there is a great deal of disagreement within the community itself over the licensing terms controlling the distribution and use of OSS. The two most fundamental and often rival OSS schools of thought can be characterized loosely by the following:

 

  • Ideological. This school of thought contends that all software (both source and object code) should be available at no cost, because software should not be privately held.
  • Pragmatic. This school of thought supports the co-existence of privately held and Open Source Software, and seeks to use both to create healthy businesses. 

 

As a result of these different philosophies, there are currently about 50 different licensing schemes governing the distribution of Open Source Software.  The Open Source Initiative (OSI) (www.opensource.org) maintains a diverse list of licenses that cover both the ideological and pragmatic approaches. These licenses vary considerably as to specific terms, even key terms, but the vast majority of OSS licenses conform to the definition provided by the OSI. Of the ten essential OSI criteria, three are relevant to this discussion. In summary, every OSS license

 

  • requires that the source code be made available to the public
  • permits anyone to redistribute the source code without material restrictions
  • permits anyone to modify the code and freely redistribute the modified code

Within these broad parameters, however, Open Source Software licenses differ widely with regard to the nature and degree of restrictions they impose on licensees. Some OSS licenses are extremely permissive, such as the Berkeley Software Distribution (BSD) license, which is a simple, permissive, software license whose only restriction is copyright attribution and license reproduction. Others are moderately restrictive, such as the Apple Public Source License (APSL) or the Mozilla Public License (MPL), which requires that specific files that contain APSL/MPL code be distributed in source code form and under the terms of the APSL/MPL (although other files that do not contain APSL/MPL code that are contained in a larger work may be released under any license). Still others include greater restrictions such as the GNU General Public License (GPL), which forbids direct commercialization of the software and requires that any work that includes GPL code be released under the terms of the GPL.