1. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Evolutional Analysis of Licenses in FOSS Yuki Manabe† Yasuhiro Hayase‡ Katsuro Inoue † †Osaka University, Japan ‡Toyo University, Japan 2010/9/21 - IWPSE2010 1

2. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Overview Statistical study on the evolution of licenses on Free Open Source Software(FOSS) – Analyzing the licenses in FreeBSD, OpenBSD, Eclipse and ArgoUML during the course of their evolution Licenses can sometimes drastically change between releases Kernel also have Great License Shifts 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 2

3. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Software license The permissions of use, and describes the requirements and conditions to get such permission. 66 licenses approved by Open Source Initiative 1 as Open Source License – Satisfying the open source definition 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 3 1 http://www.opensource.org/

4. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Ninka[6] Automatically license identification tool – Reporting license name (112 licenses) BSD3(BSD 3-clause license) GPLv2+(GNU Public License version2 or later) – Precision: 96.6% 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 4 Source File License name Knowledge base Rule matching [6]D. M. German et.al. A sentence-matching method for automatic license identification of source code files. In Proc. ASE 2010, 2010. (To appear).

5. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Evolution of licenses Software licenses are adapted to environment Software licenses evolves because of... [2] – author's requirement – user's demand – external pressure [2] only analyzed first and last versions in target versions with respect to license changes. And no detail of the evolution characteristics was analyzed 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 5 [2] M. Di Penta, D. M. German, Y.-G. Gueheneuc, and G. Antoniol. "An exploratory study of the evolution of software licensing", ICSE2010.

6. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Research theme Goal – Finding characteristics of change of licenses in the evolution of FOSS Approach – Analyzing the licenses of several releases of large-scale FOSS with Ninka 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 6

7. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Analysis targets 2010/9/21 - IWPSE2010 7 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue FreeBSD (all) FreeBSD (kernel) OpenBSD (all) OpenBSD (kernel) EclipseArgoUML TypeOS kernel, applications OS kernelOS kernel, applications OS kernelSDE platform UML Design Tools Release Version 2.2-8.02.0-4.72.0- 3.5.2 0.8.1- 0.31.1 Release Date 1994/11- 2009/11 1996/10- 2010/5 2002/6- 2009/9 2000/10- 2010/6 # release 28452579 #Files (oldest- latest) 4412- 21266 627- 3490 6245- 14181 987- 3314 11419- 35880 686- 2208 Version Control System CVS Subversion

8. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Experiments 1.Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML 2.Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) 3.Examine the difference in evolution patterns of OS all and OS kernel 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 8

9. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Experiment 1 License ratio 1.Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML 2.Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) 3.Examine the difference in evolution patterns of OS all and OS kernel 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 9

10. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University FreeBSD (all) 10 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue Decreased BSD4 Increased BSD2 and BSD3

11. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University OpenBSD (all) 11 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue Decreased BSD4 Increased BSD2 and BSD3

12. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Eclipse 12 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue CPLv0.5→CPLv1.0 CPLv1.0→EPLv1.0

13. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University ArgoUML 13 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue UNKNOWN(BSD-like license) →EPLv1.0

14. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Findings of Experiment 1 Licenses of the BSD systems are rather diverse and loosely controlled, compared to Eclipse and ArgoUML A few-license cover almost all files in Eclipse and ArgoUML Sometimes those licenses are drastically changed to others by the strong management to the overall systems Those changes relax or tighten the conditions of the license 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 14

15. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Experiment 2 License File Increase/Decrease 1.Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML 2.Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) 3.Examine the difference in evolution patterns of OS all and OS kernel 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 15

16. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University FreeBSD (all) 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 16 v5.2.1 - v5.3 531 files under BSD4 were moved to other license BSD2 or BSD3.

17. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University OpenBSD (all) 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 17 v3.3 - v3.4 2255 files under BSD4 were moved to other license BSD2 or BSD3.

18. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University OpenBSD (all) 18 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue There are large shifts of licenses along with system evolution

19. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Experiment 3 Difference of all and kernel 1.Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML 2.Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) 3.Examine the difference in evolution patterns of OS all and OS kernel 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 19

20. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University FreeBSD (all) 20 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue Decreased BSD4 Increased BSD2 and BSD3

21. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University FreeBSD (kernel) 21 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue Decreased BSD4 Increased BSD2 and BSD3

22. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University OpenBSD (all) 22 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue Decreased BSD4 Increased BSD2 and BSD3

23. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University OpenBSD (kernel) 23 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue Decreased BSD4 Increased BSD2 and BSD3 We had expected to see the different evolution pattern between kernels and alls but they are almost similar

24. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Summary of findings There are large shifts of license in FreeBSD (all) and OpenBSD (all) ArgoUML and Eclipse also have similar large shifts – Sometimes those licenses are more drastically changed to others than FreeBSD (all) and OpenBSD (all) – A few licenses cover almost all files in those systems The kernel of FreeBSD and OpenBSD also have large shifts 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 24

25. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Conclusions & Future work Statistical study on the evolution of licenses on FOSS – Analyzing the licenses in FreeBSD, OpenBSD, Eclipse and ArgoUML during the course of their evolution – Finding large shifts of licenses in evolution of FOSS Future Work – More fine-grained analysis – Analysis of the relation between drastic license change and other log data such as mailing list archive 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 25

26. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 26

27. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Supplemental Slides 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 27

28. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Advertisement clause of BSD4 3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the. 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 28

29. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Endorsement clause of BSD3 Neither the name of the nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 29

30. Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University Patent clause of CPLv1.0 In Section 7 "If Recipient institutes patent litigation against a Contributor with respect to a patent applicable to software (including a cross-claim or counterclaim in a lawsuit), then any patent licenses granted by that Contributor to such Recipient under this Agreement shall terminate as of the date such litigation is filed." 2010/9/21 - IWPSE2010Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 30