Evolutional Analysis of Licenses in FOSS

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


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 - IWPSE2010 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 2


Software license• 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


1 http://www.opensource.org/


Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue 4

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 - IWPSE2010

Source File

License name

Knowledge baseRule 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).


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


[2] M. Di Penta, D. M. German, Y.-G. Gueheneuc, and G. Antoniol. "An exploratory study of the evolution of software licensing" , ICSE2010.


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



Analysis targets

2010/9/21 - IWPSE2010 7Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

FreeBSD(all)

FreeBSD(kernel)

OpenBSD(all)

OpenBSD(kernel)

Eclipse ArgoUML

Type OS kernel,applications

OS kernel OS kernel, applications

OS kernel SDE platform

UML Design Tools

Release Version

2.2-8.0 2.0-4.7 2.0-3.5.2

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 28 45 25 79#Files(oldest-latest)

4412-21266

627-3490

6245-14181

987-3314

11419-35880

686-2208

Version Control System

CVS CVS CVS Subversion


Experiments1. 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



Experiment 1License ratio

1. Examine the number of files under each license at each release version in FreeBSD (all), OpenBSD (all), Eclipse and ArgoUML





2.2.02.2.2

2.2.62.2.8

3.1.03.3.0

3.5.04.1.0

4.2.04.4.0

4.6.04.6.2

4.8.04.10.0

5.0.05.2.0

5.3.05.5.0

6.1.06.3.0

7.0.07.2.0

8.0.00

2000

4000

6000

8000

10000

12000

14000

16000

BSD4 BSD3 BSD2 GPLv2+LibraryGPLv2+ Others NONE UNKNOWN

Release Version

#file

s

FreeBSD (all)

10

2010/9/21 - IWPSE2010 Yuki Manabe, Yasuhiro Hayase and Katsuro Inoue

Decreased BSD4 Increased BSD2 and BSD3


2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.70

5000

10000

15000

20000

25000

BSD4 BSD3 BSD2 GPLv2+MITold1 Others NONE UNKNOWN

Release Version

#file

s

OpenBSD (all)

11


Decreased BSD4Increased BSD2 and BSD3


2.02.0.1 2.1

2.1.12.1.2

2.1.3 3.03.0.1

3.0.2 3.13.1.1

3.1.2 3.23.2.1

3.2.23.3.1

3.3.1.13.3.2 3.3 3.4

3.4.13.4.2 3.5

3.5.13.5.2

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

EPLv1 CPLv0.5 CPLv1 MPLv1_1BSD3 Others NONE UNKNOWN

Release Version

#file

s

Eclipse

12


CPLv0.5→CPLv1.0 CPLv1.0→EPLv1.0


0.8.10.9.2

0.9.60.9.9

0.11.10.11.4

0.13.20.13.5

0.14.10.15.3

0.15.60.17.1

0.17.40.18.1

0.19.40.19.7

0.21.10.22

0.23.30.24

0.25.30.25.6

0.26.20.27.3

0.29.10.29.4

0.31.10

500

1000

1500

2000

2500

EPLv1 Apachev2 BSD2 LesserGPLv2.1LesserGPLv2.1+ Others UNKNOWN NONE

Release Version

#file

s

ArgoUML

13


UNKNOWN(BSD-like license)→EPLv1.0


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



Experiment 2License File Increase/Decrease






2.2.12.2.5

2.2.73.0.0

3.2.03.4.0

4.0.04.1.1

4.3.04.5.0

4.6.14.7.0

4.9.04.11.0

5.1.05.2.1

5.4.06.0.0

6.2.06.4.0

7.1.07.3.0

-800

-600

-400

-200

0

200

400

600

800

BSD4 BSD3 BSD2GPLv2+ LibraryGPLv2+

Release Version

#file

s

FreeBSD (all)


v5.2.1 - v5.3531 files under BSD4 were moved to other license BSD2 or BSD3.


2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

BSD4 BSD3 BSD2 GPLv2+ MITold1

Release Version

#file

s

OpenBSD (all)


v3.3 - v3.42255 files under BSD4 were moved to other license BSD2 or BSD3.


2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.70

5000

10000

15000

20000

25000


Release Version

#file

s

OpenBSD (all)

18


There are large shifts of licenses along with system evolution


Experiment 3Difference of all and kernel






2.2.02.2.2

2.2.62.2.8

3.1.03.3.0

3.5.04.1.0

4.2.04.4.0

4.6.04.6.2

4.8.04.10.0

5.0.05.2.0

5.3.05.5.0

6.1.06.3.0

7.0.07.2.0

8.0.00

2000

4000

6000

8000

10000

12000

14000

16000

BSD4 BSD3 BSD2 GPLv2+LibraryGPLv2+ Others NONE UNKNOWN

Release Version

#file

s

FreeBSD (all)

20




2.2.02.2.2

2.2.62.2.8

3.1.03.3.0

3.5.04.1.0

4.2.04.4.0

4.6.04.6.2

4.8.04.10.0

5.0.05.2.0

5.3.05.5.0

6.1.06.3.0

7.0.07.2.0

8.0.00

500

1000

1500

2000

2500

3000

3500

4000

BSD4 BSD3 BSD2 InterACPILicCDDLic Others NONE UNKNOWN

Release Version

#file

FreeBSD (kernel)

21




2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.70

5000

10000

15000

20000

25000


Release Version

#file

s

OpenBSD (all)

22




2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.70

500

1000

1500

2000

2500

3000

3500

BSD4 BSD3 BSD2 MITold1MITold2 Others NONE UNKNOWN

Release Version

#file

s

OpenBSD (kernel)



We had expected to see the different evolution pattern between kernels and alls

but they are almost similar


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



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


Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University27

• Supplemental Slides



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Evolutional Analysis of Licenses in FOSS

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