Evolutional Analysis of Licenses in FOSS

1. Evolutional Analysis of Licenses in FOSS Yuki Manabe† Yasuhiro Hayase‡ Katsuro Inoue† †Osaka University, Japan‡Toyo University, Japan

2. 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 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

3. Software license 1http://www.opensource.org/ • The permissions of use, and describes the requirements and conditions to get such permission. • 66 licenses approved by Open Source Initiative1 as Open Source License • Satisfying the open source definition Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

4. Ninka[6] Source File 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). License name Automatically license identification tool • Reporting license name (112 licenses) • BSD3(BSD 3-clause license) • GPLv2+(GNU Public License version2 or later) • Precision: 96.6% Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

5. Evolution of licenses [2] M. Di Penta, D. M. German, Y.-G. Gueheneuc, and G. Antoniol. "An exploratory study of the evolution of software licensing" , ICSE2010. • 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 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

6. 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 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

7. Analysis targets Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

8. Experiments • Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML • Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) • Examine the difference in evolution patterns of OS all and OS kernel Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

9. Experiment 1License ratio • Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML • Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) • Examine the difference in evolution patterns of OS all and OS kernel Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

10. FreeBSD (all) Decreased BSD4 IncreasedBSD2 and BSD3 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

11. OpenBSD(all) Decreased BSD4 Increased BSD2 and BSD3 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

12. Eclipse CPLv0.5→CPLv1.0 CPLv1.0→EPLv1.0 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

13. ArgoUML UNKNOWN(BSD-like license)→EPLv1.0 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

14. 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 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

15. Experiment 2License File Increase/Decrease • Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML • Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) • Examine the difference in evolution patterns of OS all and OS kernel Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

16. FreeBSD (all) v5.2.1 - v5.3 531 files under BSD4 were moved to other license BSD2 or BSD3. Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

17. OpenBSD (all) v3.3 - v3.4 2255 files under BSD4 were moved to other license BSD2 or BSD3. Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

18. OpenBSD(all) There are large shifts of licenses along with system evolution Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

19. Experiment 3Difference of all and kernel • Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML • Analyze the difference of licensed file number across different versions in FreeBSD(all) and OpenBSD(all) • Examine the difference in evolution patterns of OS all and OS kernel Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

20. FreeBSD (all) Decreased BSD4Increased BSD2 and BSD3 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

21. FreeBSD (kernel) Decreased BSD4 Increased BSD2 and BSD3 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

22. OpenBSD(all) Decreased BSD4 Increased BSD2 and BSD3 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

23. OpenBSD (kernel) We had expected to see the different evolution pattern between kernels and alls but they are almost similar Decreased BSD4 Increased BSD2 and BSD3 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

24. 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) • Afew licenses cover almost all files in those systems • The kernel of FreeBSD and OpenBSD also have large shifts Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

25. 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 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

26. Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

27. Supplemental Slides Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

28. 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 <organization>. Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

29. Endorsement clause of BSD3 Neither the name of the <organization> nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

30. 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." Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue