Open Source for Beginners Part 2 - Open Source Licenses
So... Open Source software is software which is given away freely, and for which the source code is freely available.
But what is to stop someone taking this source code, packaging it up as a new application and selling it as a closed source program? Sometimes nothing, but usually it's the license!
Some Open Source programs are given away with no license at all, but most are copyrighted and distributed under the some form of Open Source license.
There are dozens of such licenses. The most popular and famous is the GPL. The preamble offers a beautifully succinct description of the purpose of the GPL - take 2 minutes to read it (bearing in mind that the document uses the word "free" as in "liberty" rather than as in "no cost").
One aspect of the GPL is particularly contentious: the GPL stipulates that any programs created using portions of the code from a GPL licensed program must also be Open Source. In other words, if I grab an Open Source program, tinker with it a bit and call it something new, the GPL license under which I received the program demands that the new program I have created may only be distributed under the terms of the GPL.
Some see this feature of the GPL as a stroke of genius - guaranteeing the continued freedom of source code, but others are less impressed. Microsoft in particular does not take kindly to the GPL, and there is a long history of attempts by Microsoft to undermine Open Source.
That history will be the subject of part 3!