If I weren’t working, it would be a vacation!
In Adobe Illustrator I type the word copyright into the search box in the Help Center. The page that results includes the following paragraph:
This product includes either BISAFE and/or TIPEM software by RSA Data Security, Inc. This product includes cryptographic software written by Eric Young (email@example.com). This software is based in part on the work of the Independent JPEG Group. Portions include technology used under license from Verity, Inc. and are copyrighted. © 1994 Hewlett Packard Company. © 1985, 1986 Regents of the University of California. All rights reserved. Portions of this code are licensed from Apple Computer, Inc. under the terms of the Apple Public Source License Version 2. The source code version of the licensed code and the license are available at http://www.opensource.apple.com/apsl. This product includes PHP, freely available from http://www.php.net. This product includes the Zend Engine, freely available at http://www.zend.com. This product includes software developed by Brian M. Clapper (firstname.lastname@example.org). © 1991 by the Massachusetts Institute of Technology. ©1996, 1995 by Open Software Foundation, Inc. 1997,1996, 1995, 1994, 1993, 1992, 1991. All rights reserved.
Many open source advocates, looking inside their own organization (or others), will enumerate the open source software in use to make the case that “everybody” is “using open source”. As I start counting all the open source projects embedded in Illustrator, it seems to exceed the amount of open source software used in many of these “censuses”. By all accounts, Adobe Illustrator is an “open source” product.
Can we say that Mathematica is open source? Or “open source friendly”?
This chain of reasoning came about because of this blog post that I stumbled across. Seems like Apple was adding OCUnit to XCode. So I went looking for the equivalent copyright page for XCode (because I know it also uses gcc and gdb at a minimum). I couldn’t find such a page. The best I could find was something that advised me that this Apple product included some (unspecified) open source software, the source code of which was available here.
So, I got to thinking. Assuming rational markets. If I’m selling proprietary software in any particular application domain, and there exists some “attributive-licensed” software (MIT, BSD, Apache, etc.) which is superior in some way (faster, more featureful) than the code I wrote / licensed, wouldn’t I include it in my product? And continue to sell my product as before?
In which case, the distinction (technology-wise) between assembling a custom solution using attributive-licensed open source libraries, and buying a commercial product, seems to be ever more evanescent. (Of course, “reciprocal-licensed” (GPL’d) software may be more distinguished in this regard — depending on the nature of the integration.)