The meaning of the term "open source", is about to change, according to the Open Source Initiative (OSI), the group that determines whether or not software licenses can be called "open source".
Board members of the volunteer organisation have approved sweeping changes that will tighten up the way it classifies open-source licenses and, eventually, create a new "multi-tier" classification system that will favor some open source licenses over others.
The changes, detailed in a white paper that is expected to be published on the OSI website later this week, are intended to address the growing confusion over the large number of open source licenses currently available.
The group has tightened its procedures to make it more difficult for new licenses to receive the "open source" designation, but it has also begun the process of reclassifying existing licenses to put more emphasis on a small number of popular licenses.
Developers are increasingly concerned that they may violate the terms of one open source license when combining code that is governed by another one, the OSI believes.
"As the number of OSI-approved licenses goes up, we get a combinatorial explosion in the number of possible license collisions," the white paper states. "This is a potentially serious problem."
Even looking at the list of more than 50 open source licenses on OSI's website today could overwhelm developers who fear such collisions, an OSI board member, Russell Nelson, said.
"What we're going to do is, we're going to get rid of that flat list of licenses and we're going to tier them," he said.
The group plans to sort the current list of open source licenses into three categories: Preferred, Ordinary and Deprecated. "The goal will be to define a small enough set of Preferred licenses to make interactions among them manageable," the white paper states.
At the top tier will be a list of about six recommended open source licenses, which already cover about 80 per cent or 90 per cent of the software in Linux. These licenses will be designated as Preferred.
According to Nelson, the licenses that are expected to receive such designation include the GNU General Public License (GPL), the Lesser GPL, the Apache Software License, the Berkeley System Distribution license and the Mozilla Public License, although the OSI plans to hold a series of public discussions on the issue.
The OSI hopes that the public discussions will eventually determine the exact significance of the Ordinary or Deprecated designations, but the point will be to discourage code from being released under non-Preferred licenses, board members said.
The classification process was expected to take about six months, Nelson said.
Successfully reducing the number of licenses being used and confusion over their use will be more difficult, however. "Actually having an effect on the world? That's going to take years," he said.