@conference {Godfrey:2001:GES:602461.602482,
	title = {Growth, evolution, and structural change in open source software},
	booktitle = {Proceedings of the 4th International Workshop on Principles of Software Evolution (IWPSE 2001)},
	series = {IWPSE {\textquoteright}01},
	year = {2001},
	note = {"We measured [linux] system size in uncommented LOC"
"We also examined the growth of several other open source systems, including the VIM text editor, Eric Raymond{\textquoteright}s fetchmail utility, and the GCC compiler suite. "},
	pages = {103{\textendash}106},
	publisher = {ACM},
	organization = {ACM},
	address = {New York, NY, USA},
	abstract = {Our recent work has addressed how and why software systems evolve over time, with a particular emphasis on software architecture and open source software systems [2, 3, 6]. In this position paper, we present a short summary of two recent projects. First, we have performed a case study on the evolution of the Linux kernel [3], as well as some other open source software (OSS) systems. We have found that several OSS systems appear not to obey some of "Lehman{\textquoteright}s laws" of software evolution [5, 7], and that Linux in particular is continuing to grow at a geometric rate. Currently, we are working on a detailed study of the evolution of one of the subsystems of the Linux kernel: the SCSI drivers subsystem. We have found that cloning, which is usually considered to be an indicator of lazy development and poor process, is quite common and is even considered to be a useful practice. Second, we are developing a tool called Beagle to aid software maintainers in understanding how large systems have changed over time. Beagle integrates data from various static analysis and metrics tools and provides a query engine as well as navigable visualizations. Of particular note, Beagle aims to provide help in modelling long term evolution of systems that have undergone architectural and structural change.},
	keywords = {agile methods, beagle, cloning, evolution, fetchmail, gcc, growth, kernel, lehman{\textquoteright}s laws, lines of code, linux, linux kernel, loc, open source software, software architecture, software evolution, source code, structural change, supporting environments, vim},
	isbn = {1-58113-508-4},
	doi = {http://doi.acm.org/10.1145/602461.602482},
	url = {http://doi.acm.org/10.1145/602461.602482},
	attachments = {https://flosshub.org/sites/flosshub.org/files/tu2001.pdf},
	author = {Michael Godfrey and Tu, Qiang}
}
@conference {Godfrey:2000:EOS:850948.853411,
	title = {Evolution in Open Source Software: A Case Study},
	booktitle = {Proceedings of the International Conference on Software Maintenance (ICSM{\textquoteright}00)},
	series = {ICSM {\textquoteright}00},
	year = {2000},
	note = {"We examined 96 kernel versions..."
.c files, .h files only
loc, lines of code
number of functions
number of modules},
	pages = {131{\textendash}},
	publisher = {IEEE Computer Society},
	organization = {IEEE Computer Society},
	address = {Washington, DC, USA},
	abstract = {Most studies of software evolution have been performed on systems developed within a single company using traditional management techniques. With the widespread availability of several large software systems that have been developed using an {\textquoteright}open source{\textquoteright} development approach, we now have a chance to examine these systems in detail, and see if their evolutionary narratives are significantly different from commercially developed systems. This paper summarizes our preliminary investigations into the evolution of the best known open source system: the Linux operating system kernel. Because Linux is large (over two million lines of code in the most recent version) and because its development model is not as tightly planned and managed as most industrial software processes, we had expected to find that Linux was growing more slowly as it got bigger and more complex. Instead, we have found that Linux has been growing at a super-linear rate for several years. In this paper, we explore the evolution of the Linux kernel both at the system level and within the major subsystems, and we discuss why we think Linux continues to exhibit such strong growth.},
	keywords = {evolution, functions, growth, lines of code, linux, linux kernel, loc, source code},
	isbn = {0-7695-0753-0},
	url = {http://portal.acm.org/citation.cfm?id=850948.853411},
	attachments = {https://flosshub.org/sites/flosshub.org/files/godfrey00.pdf},
	author = {Godfrey, Michael W. and Tu, Qiang}
}
