According to the conventional licensing model, holders of copyrighted software grant proprietary licenses to 3rd parties to use the software, usually in exchange for money. Such a license restricts how the software may be used (and modified or distributed) and if the licensee exceeds those restrictions the licensor may bring an action of infringement.
The so-called Copyleft model removes most of these restrictions but does so without making the software public domain (where users could modify then copyright such works, thereby undermining the effort).FN1 Copyleft maintains the licensing framework but aggressively enlarges the scope of the license on a very specific condition: use, modification and redistribution of the software (modified or not) is unlimited so long as this same allowance is given to all future licensees. The exact wording of the original license must be preserved each time the software is modified and distributed. Whatever rights inhere in the original license are there for perpetuity. This mechanism is variously referred to as a "Reciprocal Grant, "Viral License" or "License Inheritance."
As a necessary corollary to or function of the inherited license, all source code (read-only programs are insufficient) must be made accessible to future users (so it may be modified).
These requirements don't prohibit commercialization of the software. Copyleft does not necessarily mean "free." While you cannot charge for a proprietary license, you can charge for each copy or for warranty, support, services, etc. Because selling individual copies is rarely profitable (since the seller cannot by virtue of the sale control/limit what the buyer does with the source code thereafter - like give it away for free), the value of copylefted software to corporate enterprise typically inheres in the sale of products or services in which the copylefted software is embedded.FN2
FN1. In addition to copyleft there are so-called "academic" licenses which comprise with copyleft the two main groups of open source licenses.The Gnu Project's General Public License (the GPL) is probably the best-known and most widely used copyleft license.
FN2. The chief risk is this business model is the inadvertent surrendering of ownership to proprietary software. Determining what is a "derivative work" can be an uncertain inquiry (at least in part because of limited judicial interpretation with respect to the enforceability of copyleft licenses) and thus where the open source software is mingled/bundled with proprietary software, it's possible the proprietary license will be deemed to be a derivative of open source and therefore not protected by copyright.
No comments:
Post a Comment