@article {denBesten2008316,
	title = {The allocation of collaborative efforts in open-source software},
	journal = {Information Economics and Policy},
	volume = {20},
	number = {4},
	year = {2008},
	note = {"we have selected a set of 10 large open-source projects"
apache, cvs, gaim, gcc, ghostscript, mozilla, netbsd, openssh, postgresql, python
"Our data were extracted from logs of development activity generated by software version control systems. For each project in the selection, we extracted CVS development logs"
"We notably computed for each file in the sample, and for each month in its history, the number of distinct maintainers that had committed a change during that month, and the number of commits, the blocks of code addition, each file had received during that month."
"other variables used in the regressions are proxies for the size, age, and granularity of files; the size of a file is represented as its number of lines of code (LOCs), its age by its creation date (Youth), and its granularity by the number of functions it contains."},
	pages = {316 - 322},
	abstract = {The article investigates the allocation of collaborative efforts among core developers (maintainers) of open-source software by analyzing on-line development traces (logs) for a set of 10 large projects. Specifically, we investigate whether the division of labor within open-source projects is influenced by characteristics of software code. We suggest that the collaboration among maintainers tends to be influenced by different measures of code complexity. We interpret these findings by providing preliminary evidence that the organization of open-source software development would self-adapt to characteristics of the code base, in a {\textquoteright}stigmergic{\textquoteright} manner.},
	keywords = {age, apache, complexity, cvs, division of labor, functions, gaim, gcc, ghostscript, lines of code, loc, log files, mozilla, netbsd, openssh, postgresql, python, revision control, scm, size, source code, Stigmergy, version control},
	issn = {0167-6245},
	doi = {DOI: 10.1016/j.infoecopol.2008.06.003},
	url = {http://www.sciencedirect.com/science/article/B6V8J-4SSG4PN-1/2/88b3824c30a31c18929d8a5ca6d64f62},
	author = {den Besten, Matthijs and Jean-Michel Dalle and Galia, Fabrice}
}
@conference {682,
	title = {Collaborative Maintenance in Large Open-Source Projects},
	booktitle = {OSS2006: Open Source Systems (IFIP 2.13)},
	series = {IFIP International Federation for Information Processing},
	year = {2006},
	pages = {233 - 244},
	publisher = {Springer},
	organization = {Springer},
	abstract = {The paper investigates collaborative work among maintainers of open source software by analyzing the logs of a set of 10 large projects. We inquire whether teamwork can be influenced by several characteristics of code. Preliminary results suggest that collaboration among maintainers in most large open-source projects seems to be positively influenced by file vintage and by Halstead volume of files, and negatively by McCabe complexity and size measured in SLOCs. These results could be consistent with an increased attractivity of files created early in the history of a project, and with maintainers being less attracted by more verbose code and by more complex code, although in this last case it might also reflect the fact that more complex files would be de facto more exclusive in terms of maintenance.
},
	keywords = {apache, COLLABORATION, complexity, cvs, gaim, gcc, ghostscript, halstead, lines of code, loc, mccabe, mozilla, netbsd, openssh, postgresql, python, sloc},
	doi = {http://dx.doi.org/10.1007/0-387-34226-5_23},
	attachments = {https://flosshub.org/sites/flosshub.org/files/Collaborative\%20Maintenance.pdf},
	author = {den Besten, Matthijs and Jean-Michel Dalle and Galia, Fabrice}
}
@conference {Askari:2006:ITE:1137983.1138013,
	title = {Information theoretic evaluation of change prediction models for large-scale software},
	booktitle = {Proceedings of the 2006 international workshop on Mining software repositories},
	series = {MSR {\textquoteright}06},
	year = {2006},
	pages = {126{\textendash}132},
	publisher = {ACM},
	organization = {ACM},
	address = {New York, NY, USA},
	abstract = {In this paper, we analyze the data extracted from several open source software repositories. We observe that the change data follows a Zipf distribution. Based on the extracted data, we then develop three probabilistic models to predict which files will have changes or bugs. The first model is Maximum Likelihood Estimation (MLE), which simply counts the number of events, i.e., changes or bugs, that happen to each file and normalizes the counts to compute a probability distribution. The second model is Reflexive Exponential Decay (RED) in which we postulate that the predictive rate of modification in a file is incremented by any modification to that file and decays exponentially. The third model is called RED-Co-Change. With each modification to a given file, the RED-Co-Change model not only increments its predictive rate, but also increments the rate for other files that are related to the given file through previous co-changes. We then present an information-theoretic approach to evaluate the performance of different prediction models. In this approach, the closeness of model distribution to the actual unknown probability distribution of the system is measured using cross entropy. We evaluate our prediction models empirically using the proposed information-theoretic approach for six large open source systems. Based on this evaluation, we observe that of our three prediction models, the RED-Co-Change model predicts the distribution that is closest to the actual distribution for all the studied systems.},
	keywords = {bugs, change analysis, cvs, evaluation approach, file, freebsd, information theory, kde, koffice, log files, netbsd, openbsd, postgresql, prediction, prediction models, scm, source code},
	isbn = {1-59593-397-2},
	doi = {http://doi.acm.org/10.1145/1137983.1138013},
	url = {http://doi.acm.org/10.1145/1137983.1138013},
	attachments = {https://flosshub.org/sites/flosshub.org/files/126InformationTheoretic.pdf},
	author = {Askari, Mina and Holt, Ric}
}
@article {Yu:2006:MKO:1150566.1150571,
	title = {Maintainability of the kernels of open-source operating systems: A comparison of Linux with FreeBSD, NetBSD, and OpenBSD},
	journal = {J. Syst. Softw.},
	volume = {79},
	year = {2006},
	note = {"Data regarding the number and total number of lines of code of kernel and nonkernel modules in the four operating systems are provided in Table 1"
loc, kloc, number of kernel modules, number of nonkernel modules
size 
c files
.h files},
	month = {June},
	pages = {807{\textendash}815},
	publisher = {Elsevier Science Inc.},
	address = {New York, NY, USA},
	abstract = {We compared and contrasted the maintainability of four open-source operating systems: Linux, FreeBSD, NetBSD, and OpenBSD. We used our categorization of common coupling in kernel-based software to highlight future maintenance problems. An unsafe definition is a definition of a global variable that can affect a kernel module if that definition is changed. For each operating system we determined a number of measures, including the number of global variables, the number of instances of global variables in the kernel and overall, as well as the number of unsafe definitions in the kernel and overall. We also computed the value of each our measures per kernel KLOC and per KLOC overall. For every measure and every ratio, Linux compared unfavorably with FreeBSD, NetBSD, and OpenBSD. Accordingly, we are concerned about the future maintainability of Linux. },
	keywords = {abiword, Common coupling, coupling, Definition-use analysis, freebsd, kernel, lines of code, linux, linux kernel, loc, Maintainability, modules, netbsd, Open-source software, openbsd, source code},
	issn = {0164-1212},
	doi = {http://dx.doi.org/10.1016/j.jss.2005.08.014},
	url = {http://dx.doi.org/10.1016/j.jss.2005.08.014},
	attachments = {https://flosshub.org/sites/flosshub.org/files/YuSchachChen.pdf},
	author = {Yu, Liguo and Schach, Stephen R. and Chen, Kai and Heller, Gillian Z. and Offutt, Jeff}
}
@conference {Fischer:2005:MED:1083142.1083145,
	title = {Mining evolution data of a product family},
	booktitle = {Proceedings of the 2005 international workshop on Mining software repositories},
	series = {MSR {\textquoteright}05},
	year = {2005},
	pages = {12-16},
	publisher = {ACM},
	organization = {ACM},
	address = {New York, NY, USA},
	abstract = {Diversification of software assets through changing requirements impose a constant challenge on the developers and maintainers of large software systems. Recent research has addressed the mining for data in software repositories of single products ranging from fine- to coarse grained analyses. But so far, little attention has been payed to mining data about the evolution of product families. In this work, we study the evolution and commonalities of three variants of the BSD (Berkeley Software Distribution), a large open source operating system. The research questions we tackle are concerned with how to generate high level views of the system discovering and indicating evolutionary highlights. To process the large amount of data, we extended our previously developed approach for storing release history information to support the analysis of product families. In a case study we apply our approach on data from three different code repositories representing about 8.5GB of data and 10 years of active development.},
	keywords = {bsd, change analysis, change history, cvs, evolution, freebsd, netbsd, openbsd, release history, source code, text mining},
	isbn = {1-59593-123-6},
	doi = {http://doi.acm.org/10.1145/1082983.1083145},
	url = {http://doi.acm.org/10.1145/1082983.1083145},
	attachments = {https://flosshub.org/sites/flosshub.org/files/12MiningEvolution.pdf},
	author = {Fischer, Michael and Oberleitner, Johann and Ratzinger, Jacek and Gall, Harald}
}
