“What’s the best book to read for an introduction to Open Source?”
I’ve already given one set of answers to this question, in my article, “Clear thinking about open source“. One reply to that article – from Joel West, a writer and researcher on Open Innovation and Open Source whose advice I value – urged me to include one more book in my reading list: Lawrence Rosen’s “Open Source Licensing: software freedom and intellectual property law“. This weekend I’ve finished reading it. And indeed, I do now endorse it as being clearly written yet also highly insightful.
Initally, I tended to shy away from this book, instead preferring the book by Heather Meeker that I covered in my earlier article. Both books focus on open source licensing issues, but Meeker’s was published this year, whereas Rosen’s dates from 2004. So Rosen’s book makes no mention of GPL v3, or Sun’s experience with open-sourcing Java, or even the Eclipse Public License (EPL) which the Symbian Foundation is likely to adopt. That makes Rosen’s book appear out of date. However, I realised that one license which the book does cover (comprehensively) is the Common Public License (CPL) which is the precursor of the EPL and which differs from the EPL in very few places. Reassured, I dipped into the book – and then could hardly put it down.
In summary, I now recommend both the Meeker book and the Rosen book for their coverage of open source licensing. They complement each other nicely. There’s a bit of overlap, but also lots of good material in each book that you won’t find in the other.
Specifically, here are a few of the “aha”s or other learnings I took away from Rosen’s book:
1.) The ten principles of the Open Source Definition are actually quite hard to understand in places (this comment came as a relief to me, since I had been thinking the same thing).
2.) Patents and Copyrights should be approached as parallel sets of legal principle – the former applicable to ideas, and the latter to expressions of ideas. That’s a far better approach than initially just thinking about Copyrights, and then trying to squeeze in considerations about Patents at the end.
3.) One of the key differences between different open source licenses is in the treatment of patent licenses – and in the different circumstances in which patent licenses (and/or copyright licenses) can be withdrawn in the wake of various kinds of patent infringement suits. There’s a tricky balance that has to be drawn between the needs of both licensor and licensee concerning the continuing value of their respective patent portfolios.
4.) One piece of license evolution covered in the book – the difference between v2.0 and v2.1 of the Open Software License (OSL) – closely mirrors the principal difference between the CPL and the EPL: it’s a reduction in the circumstances in which a patent license can be withdrawn when a licensee brings a separate patent infringement case against the licensor.
5.) The insistence in GPL v2 about not being compatible with other licenses that introduce additional restrictions (even restrictions that the initial drafters of GPL v2 had not considered), is a real drawback of that license, since it unnecessarily hinders aggregation of code written under similar but different licenses. (Possible restrictions that have emerged more recently include provisions for defence against patent infringement lawsuits or to protect the licensor’s trademarks.)
6.) “… sections of the LGPL are an inpenetrable maze of technological babble. They should not be in a general purpose software license.” (page 124)
7.) Disclaimers of liability that are generally written into open source licenses may be overridden by general consumer legislation. Recognising this, the CPL (and hence the EPL) introduces a clause that allocates particular responsibility to “commercial contributors” to defend and indemnify all other contributors against losses, damages, or costs.
8.) One possible way for a company to make money from software is via the mechanism Rosen calls “Eventual Source”: code is released as open source after some delay period, but recipients can elect to pay an early access license fee to be able to work with the code (under a non-open source license) ahead of its release as open source.
I’ve still got lots of questions about open source licensing (for example, about the prospects for wider adoption of GPL v3, and about how successful Rosen’s own preferred OSL is likely to be in the longer run). I’ll be attending the Open Source in Mobile conference in Berlin in September, when I hope to find out more answers! (And no doubt there will be new questions too…)