This paper presents size estimates (and their implications) of the source code of a distribution of the Linux operating system (OS), a combination often called GNU/Linux. The distribution used in this paper is Red Hat Linux version 6.2, including the kernel, software development tools, graphics interfaces, client applications, and so on. Other distributions and versions will have different sizes.
In total, this distribution includes well over 17 million lines of physical source lines of code (SLOC). Using the COCOMO cost model, this is estimated to have required over 4,500 person-years of development time. Had this Linux distribution been developed by conventional proprietary means, it's estimated that it would have cost over $600 million to develop in the U.S. (in year 2000 dollars).
Many other interesting statistics emerge. The largest components (in order) were the linux kernel (including device drivers), the X-windows server (for the graphical user interface), egcs (a compilation system), and emacs (a text editor and far more). The languages with the most lines of code were (in order): C, C++, LISP (including Emacs' LISP and Scheme), shell (including ksh), and perl; many other languages were also represented. More information is available at http://www.dwheeler.com/sloc.
There appear to be many reasons for this, and not simply because Linux can be obtained at no or low cost. For example, experiments suggest that Linux is highly reliable. A 1995 study of a set of individual components found that the GNU and Linux components had a significantly higher reliability than their proprietary Unix competitors (6% to 9% failure rate with GNU and Linux, versus an average 23% failure rate with the proprietary software using their measurement technique) [Miller 1995]. A ten-month experiment in 1999 by ZDnet found that, while Microsoft's Windows NT crashed every six weeks under a ``typical'' intranet load, using the same load and request set the Linux systems (from two different distributors) never crashed [Vaughan-Nichols 1999].
However, possibly the most important reason for Linux's popularity among many developers and users is that its source code is generally ``open source software'' and/or ``free software'' (where the ``free'' here means ``freedom''). A program that is ``open source software'' or ``free software'' is essentially a program whose source code can be obtained, viewed, changed, and redistributed without royalties or other limitations of these actions. A more formal definition of ``open source software'' is available at OSI , a more formal definition of ``free software'' is available at FSF , and other general information about these topics is available at Wheeler . The Linux operating system is actually a suite of components, including the Linux kernel on which it is based, and it is packaged, sold, and supported by a variety of distributors. The Linux kernel is ``open source software''/``free software'', and this is also true for all (or nearly all) other components of a typical Linux distribution. Open source software/free software frees users from being captives of a particular vendor, since it permits users to fix any problems immediately, tailor their system, and analyze their software in arbitrary ways.
Surprisingly, although anyone can analyze Linux for arbitrary properties, I have found little published analysis of the amount of source lines of code (SLOC) contained in a Linux distribution. The only published data I've found was developed by Microsoft in the documents usually called ``Halloween I'' and ``Halloween II''. Unfortunately, the meaning, derivation, and assumptions of their numbers is not explained, making the numbers hard to use and truly understand. Even worse, although the two documents were written by essentially the same people at the same time, the numbers in the documents appear (on their surface) to be contradictory. The so-called ``Halloween I'' document claimed that the Linux kernel (x86 only) was 500,000 lines of code, the Apache web server was 80,000 lines of code, the X-windows server was 1.5 million, and a full Linux distribution was about 10 million lines of code [Halloween I]. The ``Halloween II'' document seemed to contradict this, saying that ``Linux'' by 1998 included 1.5 million lines of code. Since ``version 2.1.110'' is identified as the version number, presumably this only measures the Linux kernel, and it does note that this measure includes all Linux ports to various architectures [Halloween II]. However, this asks as many questions as it answers - what exactly was being measured, and what assumptions were made? For example, is the Linux kernel support for other architectures really one million lines of code?
This paper bridges this gap. In particular, it shows estimates of the size of Linux, and it estimates how much it would cost to rebuild a typical Linux distribution using traditional software development techniques. Various definitions and assumptions are included, so that others can understand exactly what these numbers mean.
For my purposes, I have selected as my ``representative'' Linux distribution Red Hat Linux version 6.2. I believe this distribution is reasonably representative for several reasons:
Different distributions and versions would produce different size figures, but I hope that this paper will be enlightening even though it doesn't try to evaluate ``all'' distributions. Note that some distributions (such as SuSE) may decide to add many more applications, but also note this would only create larger (not smaller) sizes and estimated levels of effort. At the time that I began this project, version 6.2 was the latest version of Red Hat Linux available, so I selected that version for analysis.
Section 2 briefly describes the approach used to estimate the ``size'' of this distribution (most of the details are in Appendix A). Section 3 discusses some of the results (with the details in Appendix B). Section 4 presents conclusions, followed by the two appendices.
This was not as easy as it sounds; the steps and assumptions made are described in Appendix A.
A few summary points are worth mentioning here, however, for those who don't read appendix A. I included software for all architectures, not just the i386. I did not include ``old'' versions of software (with the one exception of bash, as discussed in appendix A). I used md5 checksums to identify and ignore duplicate files, so if the same file contents appeared in more than one file, it was only counted once. The code in makefiles and RPM package specifications was not included. Various heuristics were used to detect automatically generated code, and any such code was also excluded from the count. A number of other heuristics were used to determine if a language was a source program file, and if so, what its language was.
The ``physical source lines of code'' (physical SLOC) measure was used as the primary measure of SLOC in this paper. Less formally, a physical SLOC in this paper is a line with something other than comments and whitespace (tabs and spaces). More specifically, physical SLOC is defined as follows: ``a physical source line of code is a line ending in a newline or end-of-file marker, and which contains at least one non-whitespace non-comment character.'' Comment delimiters (characters other than newlines starting and ending a comment) were considered comment characters. Data lines only including whitespace (e.g., lines with only tabs and spaces in multiline strings) were not included.
Note that the ``logical'' SLOC is not the primary measure used here; one example of a logical SLOC measure would be the ``count of all terminating semicolons in a C file.'' The ``physical'' SLOC was chosen instead of the ``logical'' SLOC because there were so many different languages that needed to be measured. I had trouble getting freely-available tools to work on this scale, and the non-free tools were too expensive for my budget (nor is it certain that they would have fared any better). Since I had to develop my own tools, I chose a measure that is much easier to implement. Park  actually recommends the use of the physical SLOC measure (as a minimum), for this and other reasons. There are disadvantages to the ``physical'' SLOC measure. In particular, physical SLOC measures are sensitive to how the code is formatted. However, logical SLOC measures have problems too. First, as noted, implementing tools to measure logical SLOC is more difficult, requiring more sophisticated analysis of the code. Also, there are many different possible logical SLOC measures, requiring even more careful definition. Finally, a logical SLOC measure must be redefined for every language being measured, making inter-language comparisons more difficult. For more information on measuring software size, including the issues and decisions that must be made, see Kalb , Kalb , and Park .
This decision to use physical SLOC also implied that for an effort estimator I needed to use the original COCOMO cost and effort estimation model (see Boehm ), rather than the newer ``COCOMO II'' model. This is simply because COCOMO II requires logical SLOC as an input instead of physical SLOC.
For programmer salary averages, I used a salary survey from the September 4, 2000 issue of ComputerWorld; their survey claimed that this annual programmer salary averaged $56,286 in the United States. I was unable to find a publicly-backed average value for overhead, also called the ``wrap rate.'' This value is necessary to estimate the costs of office space, equipment, overhead staff, and so on. I talked to two cost analysts, who suggested that 2.4 would be a reasonable overhead (wrap) rate. Some Defense Systems Management College (DSMC) training material gives examples of 2.3 (125.95%+100%) not including general and administrative (G&A) overhead, and 2.8 when including G&A (125% engineering overhead, plus 25% on top of that amount for G&A) [DSMC]. This at least suggests that 2.4 is a plausible estimate. Clearly, these values vary widely by company and region; the information provided in this paper is enough to use different numbers if desired.
SLOC Directory SLOC-by-Language (Sorted) 1526722 linux ansic=1462165,asm=59574,sh=2860,perl=950,tcl=414, yacc=324,lex=230,awk=133,sed=72 1291745 XFree86-3.3.6 ansic=1246420,asm=14913,sh=13433,tcl=8362,cpp=4358, yacc=2710,perl=711,awk=393,lex=383,sed=57,csh=5 720112 egcs-1.1.2 ansic=598682,cpp=75206,sh=14307,asm=11462,yacc=7988, lisp=7252,exp=2887,fortran=1515,objc=482,sed=313,perl=18 652087 gdb-19991004 ansic=587542,exp=37737,sh=9630,cpp=6735,asm=4139, yacc=4117,lisp=1820,sed=220,awk=142,fortran=5 625073 emacs-20.5 lisp=453647,ansic=169624,perl=884,sh=652,asm=253, csh=9,sed=4 467120 binutils-184.108.40.206.22 ansic=407352,asm=27575,exp=12265,sh=7398,yacc=5606, cpp=4454,lex=1479,sed=557,lisp=394,awk=24,perl=16 415026 glibc-2.1.3 ansic=378753,asm=30644,sh=2520,cpp=1704,awk=910, perl=464,sed=16,csh=15 327021 tcltk-8.0.5 ansic=240093,tcl=71947,sh=8531,exp=5150,yacc=762, awk=273,perl=265 247026 postgresql-6.5.3 ansic=207735,yacc=10718,java=8835,tcl=7709,sh=7399, lex=1642,perl=1206,python=959,cpp=746,asm=70,csh=5,sed=2 235702 gimp-1.0.4 ansic=225211,lisp=8497,sh=1994 231072 Mesa ansic=195796,cpp=17717,asm=13467,sh=4092 222220 krb5-1.1.1 ansic=192822,exp=19364,sh=4829,yacc=2476,perl=1528, awk=393,python=348,lex=190,csh=147,sed=123 206237 perl5.005_03 perl=94712,ansic=89366,sh=15654,lisp=5584,yacc=921 205082 qt-2.1.0-beta1 cpp=180866,ansic=20513,yacc=2284,sh=538,lex=464, perl=417 200628 Python-1.5.2 python=100935,ansic=96323,lisp=2353,sh=673,perl=342, sed=2 199982 gs5.50 ansic=195491,cpp=2266,asm=968,sh=751,lisp=405,perl=101 193916 teTeX-1.0 ansic=166041,sh=10263,cpp=9407,perl=3795,pascal=1546, yacc=1507,awk=522,lex=323,sed=297,asm=139,csh=47,lisp=29 155035 bind-8.2.2_P5 ansic=131946,sh=10068,perl=7607,yacc=2231,cpp=1360, csh=848,awk=753,lex=222 140130 AfterStep-APPS-20000124 ansic=135806,sh=3340,cpp=741,perl=243 138931 kdebase cpp=113971,ansic=23016,perl=1326,sh=618 138118 gtk+-1.2.6 ansic=137006,perl=479,sh=352,awk=274,lisp=7 138024 gated-3-5-11 ansic=126846,yacc=7799,sh=1554,lex=877,awk=666,csh=235, sed=35,lisp=12 133193 kaffe-1.0.5 java=65275,ansic=62125,cpp=3923,perl=972,sh=814, asm=84 131372 jade-1.2.1 cpp=120611,ansic=8228,sh=2150,perl=378,sed=5 128672 gnome-libs-1.0.55 ansic=125373,sh=2178,perl=667,awk=277,lisp=177
Note that the operating system kernel (linux) is the largest single component, at over 1.5 million lines of code (mostly in C). See section 3.2 for a more discussion discussion of the linux kernel.
The next largest component is the X windows server, a critical part of the graphical user interface (GUI). Given the importance of GUIs, the long history of this program (giving it time to accrete functionality), and the many incompatible video displays it must support, this is perhaps not surprising.
Next is the compilation system, including the C and C++ compilers. Following this is the symbolic debugger and emacs. Emacs is probably not a real surprise; some users use nothing but emacs (e.g., reading their email via emacs), using emacs as a kind of virtual operating system. This is followed by the set of utilities for binary files, and the C library (which is actually used by most other language libraries as well). This is followed by TCL/Tk (a combined language and widget set), PostgreSQL (a relational DBMS), and the GIMP (an excellent client application for editing bitmapped drawings).
Note that language implementations tend to be written in themselves, particularly for their libraries. Thus there is more Perl than any other single language in the Perl implementation, more Python than any other single language in Python, and more Java than any other single language in Kaffe (an implementation of the Java Virtual Machine and library).
I found that over 870,000 lines of this code was in the ``drivers'' subdirectory, thus, the primary reason the kernel is so large is that it supports so many different kinds of hardware. The linux kernel's design is expressed in its source code directory structure, and no other directory comes close to this size - the second largest is the ``arch'' directory (at over 230,000 SLOC), which contains the architecture-unique code for each CPU architecture. Supporting many different filesystems also increases its size, but not as much as expected; the entire filesystem code is not quite 88,000 SLOC. See the appendix for more detail.
Richard Stallman and others have argued that the resulting system often called ``Linux'' should instead be called ``GNU/Linux'' [Stallman 2000]. In particular, by hiding GNU's contributions (through not including GNU's name), many people are kept unaware of the GNU project and its purpose, which is to encourage a transition to ``free software'' (free as in freedom). Certainly, the resulting system was the intentional goal and result of the GNU project's efforts. Another argument used to justify the term ``GNU/Linux'' is that it is confusing if both the entire operating system and the operating system kernel are both called ``Linux''. Using the term ``Linux'' is particularly bizarre for GNU/Hurd, which takes the Debian GNU/Linux distribution and swaps out one component: the Linux kernel.
The data here can be used to justify calling the system either ``Linux'' or ``GNU/Linux.'' It's clear that the largest single component in the operating system is the Linux kernel, so it's at least understandable how so many people have chosen to name the entire system after its largest single component (``Linux''). It's also clear that there are many contributors, not just the GNU project itself, and some of those contributors do not agree with the GNU project's philosophy. On the other hand, many of the largest components of the system are essentially GNU projects: egcs (gcc), gdb, emacs, binutils (a set of commands for binary files), and glibc (the C library). Other GNU projects in the system include binutils, bash, gawk, make, textutils, sh-utils, gettext, readline, automake, tar, less, findutils, diffutils, and grep. This is not even counting GNOME, a GNU project. In short, the total of the GNU project's code is much larger than the Linux kernel's size. Thus, by comparing the total contributed effort, it's certainly justifiable to call the entire system ``GNU/Linux'' and not just ``Linux.''
These measurements at least debunk one possible explanation of the Halloween documents' measures. Since Halloween I claimed that the x86-only code for the Linux kernel measured 500,000 SLOC, while Halloween II claimed that the kernel (all architectures) was 1.5 million SLOC, one explanation of this difference would be that the code for non-x86 systems was 1 million SLOC. This isn't so; I computed a grand total of 267,320 physical SLOC of non-i86 code (including drivers and architecture-specific code). It seems unlikely that over 700,000 lines of code would have been removed (not added) in the intervening time.
However, other measures (and explanations) are more promising. I also ran the CodeCount tools on the linux operating system kernel. Using the CodeCount definition of C logical lines of code, CodeCount determined that this version of the linux kernel included 673,627 logical SLOC in C. This is obviously much smaller than the 1,462,165 of physical SLOC in C, or the 1,526,722 SLOC when all languages are combined for the Linux kernel. When I removed all non-i86 code and re-ran the CodeCount tool on just the C code, a logical SLOC of 570,039 of C code was revealed. Since the Halloween I document reported 500,000 SLOC (when only including x86 code), it appears very likely that the Halloween I paper counted logical SLOC (and only C code) when reporting measurements of the linux kernel. However, the other Halloween I measures appear to be physical SLOC measures: their estimate of 1.5 million SLOC for the X server is closer to the 1.2 million physical SLOC measured here, and their estimate of 80,000 SLOC for Apache is close to the 77,873 SLOC measured here (as shown in Appendix B). These variations in measurements should be expected, since the versions I am measuring are slightly different than the ones they measured, and it is likely that some assumptions are different as well. Meanwhile, Halloween II reported a measure of 1.5 million lines of code for the linux kernel, essentially the same value given here for physical SLOC.
In short, it appears that Halloween I used the ``logical SLOC'' measure when measuring the Linux kernel, while all other measures in Halloween I and II used physical SLOC as the measure. I have attempted to contact the Microsoft author to confirm this, but as of yet I have not received such confirmation. In any case, this example clearly demonstrates the need to carefully identify the units of measure and assumptions made in any measurement of SLOC.
Here are the various programming languages, sorted by the total number of source lines of code:
ansic: 14218806 (80.55%) cpp: 1326212 (7.51%) lisp: 565861 (3.21%) sh: 469950 (2.66%) perl: 245860 (1.39%) asm: 204634 (1.16%) tcl: 152510 (0.86%) python: 140725 (0.80%) yacc: 97506 (0.55%) java: 79656 (0.45%) exp: 79605 (0.45%) lex: 15334 (0.09%) awk: 14705 (0.08%) objc: 13619 (0.08%) csh: 10803 (0.06%) ada: 8217 (0.05%) pascal: 4045 (0.02%) sed: 2806 (0.02%) fortran: 1707 (0.01%)
Here you can see that C is pre-eminent (with over 80% of the code), followed by C++, LISP, shell, and Perl. Note that the separation of Expect and TCL is somewhat artificial; if combined, they would be next (at 232115), followed by assembly. Python, yacc, Java, lex, and awk make respectable showings as well. Some of the languages with smaller counts (such as objective-C and Ada) show up primarily as test cases or bindings to support users of those languages. Nevertheless, it's nice to see at least some support for a variety of languages, since each language has some strength for some type of application.
C++ has over a million lines of code, a very respectable showing, and yet at least in this distribution it is far less than C. One could ask why there's so much more C code, particularly against C++. One possible argument is that well-written C++ takes fewer lines of code than does C; while this is often true, that's unlikely to entirely explain this. Another important factor is that many of the larger programs were written before C++ became widely used, and no one wishes to rewrite their C programs into C++. Also, there are a significant number of software developers who prefer C over C++ (e.g., due to simplicity of understanding the entire language), which would certainly affect these numbers. There have been several efforts in the past to switch from C to C++ in the Linux kernel, and they have all failed (for a variety of reasons).
The fact that LISP places so highly (it's in third place) is a little surprising. LISP is used in many components, but its high placement is due to the widespread use of emacs. Emacs itself is written in primarily in its own variant of LISP, and the emacs package itself accounts for 80% (453647/565861) of the total amount of LISP code. In addition, many languages include sophisticated (and large) emacs modes to support development in those languages: Perl includes 5584 lines of LISP, and Python includes another 2333 of LISP that is directly used to support elaborate Emacs modes for program editing. The ``psgml'' package is solely an emacs mode for editing SGML documents. The components with the second and third largest amounts of LISP are xlispstat-3-52-17 and scheme-3.2, which are implementations of LISP and Scheme (a LISP dialect) respectively. Other programs (such as the GIMP and Sawmill) also use LISP or one of its variants as a ``control'' language to control components built in other languages (in these cases C). LISP has a long history of use in the hacking (computer enthusiast) community, due to powerful influences such as MIT's old ITS community. For more information on the history of hackerdom, including the influence of ITS and LISP, see [Raymond 1999].
Lex/flex and yacc/bison are widely-used program generators. They make respectable showings when counting SLOC, but their widespread use is more obvious when examining the file counts. There are 57 different lex/flex files, and 110 yacc/bison files. Since some build directories use lex/flex or yacc/bison more than once, the count of build directories using these tools is smaller but still respectable: 38 different build directories use lex/flex, and 62 different build directories use yacc/bison.
Other insights can be gained from the file counts shown in appendix B. The number of source code files counted were 72,428. Not included in this count were 5,820 files which contained duplicate contents, and 817 files which were detected as being automatically generated.
These values can be used to compute average SLOC per file across the entire system. For example, for C, there was 14218806 SLOC contained in 52088 files, resulting in an ``average'' C file containing 273 (14218806/52088) physical source lines of code.
|NASA Space Shuttle flight control||420K (shuttle) + 1.4 million (ground)|
|Sun Solaris (1998-2000)||7-8 million|
|Microsoft Windows 3.1 (1992)||3 million|
|Microsoft Windows 95||15 million|
|Microsoft Windows 98||18 million|
|Microsoft Windows NT (1992)||4 million|
|Microsoft Windows NT 5.0 (1998)||20 million|
These numbers come from Bruce Schneier's Crypto-Gram [Schneier 2000], except for the Space Shuttle numbers which come from a National Academy of Sciences study [NAS 1996]. Numbers for later versions of Microsoft products are not shown here because their values have great uncertainty in the published literature. The assumptions of these numbers are unclear (e.g., are these physical or logical lines of code?), but they are likely to be comparable physical SLOC counts.
Schneier also reports that ``Linux, even with the addition of X Windows and Apache, is still under 5 million lines of code''. At first, this seems to be contradictory, since this paper counts over 17 million SLOC, but Schneier appears to be literally correct in the context of his statement. The phrasing of his sentence suggests that Schneier is considering some sort of ``minimal'' system, since he considers ``even the addition of X Windows'' as a significant addition. As shown in appendix section B.4, taking the minimal ``base'' set of components in Red Hat Linux, and then adding the minimal set of components for graphical interaction (the X Windows's graphical server, library, configuration tool, and a graphics toolkit) and the Apache web server, the total is about 4.4 million physical SLOC - which is less than 5 million. This minimal system doesn't include some useful (but not strictly necessary) components, but a number of useful components could be added while still staying under a total of 5 million SLOC.
However, note the contrast. Many Linux distributions include with their operating systems many applications (e.g., bitmap editors) and development tools (for many different languages). As a result, the entire delivered system for such distributions (including Red Hat Linux 6.2) is much larger than the 5 million SLOC stated by Schneier. In short, this distribution's size appears similar to the size of Windows 98 and Windows NT 5.0 in 1998.
Microsoft's recent legal battles with the U.S. Department of Justice (DoJ) also involve the bundling of applications with the operating system. However, it's worth noting some differences. First, and most important legally, a judge has ruled that Microsoft is a monopoly, and under U.S. law monopolies aren't allowed to perform certain actions that other organizations may perform. Second, anyone can take Linux, bundle it with an application, and redistribute the resulting product. There is no barrier such as ``secret interfaces'' or relicensing costs that prevent anyone from making an application work on or integrate with Linux. Third, many Linux distributions include alternatives; users can choose between a number of options, all on the CD-ROM. Thus, while Linux distributions also appear to be going in the direction of adding applications to their system, they do not do so in a way that significantly interferes with a user's ability to select between alternatives.
It's worth noting that SLOC counts do not necessarily measure user functionality very well. For example, smart developers often find creative ways to simplify problems, so programs with small SLOC counts can often provide greater functionality than programs with large SLOC counts. However, there is evidence that SLOC counts correlate to effort (and thus development time), so using SLOC to estimate effort is still valid.
Creating reliable code can require much more effort than creating unreliable code. For example, it's known that the Space Shuttle code underwent rigorous testing and analysis, far more than typical commercial software undergoes, driving up its development costs. However, it cannot be reasonably argued that reliability differences between Linux and either Solaris or Windows NT would necessary cause Linux to take less effort to develop for a similar size. To see this, let's pretend that Linux had been developed using traditional proprietary means and a similar process to these other products. As noted earlier, experiments suggest that Linux, or at least certain portions of it, is more reliable than either. This would either cost more money (due to increased testing) or require a substantive change in development process (e.g., through increased peer review). Therefore, Linux's reliability suggests that developing Linux traditionally (at the same level of reliability) would have taken at least the same amount of effort if similar development processes were used as compared to similarly-sized systems.
Total Physical Source Lines of Code (SLOC) = 17652561 Total Estimated Person-Years of Development = 4548.36 Average Programmer Annual Salary = 56286 Overhead Multiplier = 2.4 Total Estimated Cost to Develop = $ 614421924.71
See appendix A for more data on how these effort values were calculated; you can retrieve more information from http://www.dwheeler.com/sloc.
Many other interesting statistics emerge. The largest components (in order) were the linux kernel (including device drivers), the X-windows server (for the graphical user interface), egcs (a compilation system), and emacs (a text editor and far more). The languages with the most lines of code were (in order): C, C++, LISP (including Emacs' LISP and Scheme), shell (including ksh), and perl. More information is available in the appendices and at http://www.dwheeler.com/sloc.
It would be interesting to re-run these values on other Linux distributions (such as SuSE and Debian), other open source systems (such as FreeBSD), and other versions of Red Hat (such as Red Hat 7). SuSE and Debian, for example, by policy include many more packages, and would probably produce significantly larger estimates of effort and development cost. It's known that Red Hat 7 includes more source code; Red Hat 7 has had to add another CD-ROM to contain the binary programs, and adds such capabilities as a word processor (abiword) and secure shell (openssh).
Some actions by developers could simplify further similar analyses. The most important would be for programmers to always mark, at the top, any generated files (e.g., with a phrase like ``Automatically generated''). This would do much more than aid counting tools - programmers are likely to accidentally manually edit such files unless the files are clearly marked as files that should not be edited. It would be useful if developers would use file extensions consistently and not ``reuse'' extension names for other meanings; the suffixes(7) manual page lists a number of already-claimed extensions. This is more difficult for less-used languages; many developers have no idea that ``.m'' is a standard extension for objective-C. It would also be nice to have high-quality open source tools for performing logical SLOC counting on all of the languages represented here.
It should be re-emphasized that these are estimates; it is very difficult to precisely categorize all files, and some files might confuse the size estimators. Some assumptions had to be made (such as not including makefiles) which, if made differently, would produce different results. Identifying automatically-generated files is very difficult, and it's quite possible that some were miscategorized.
Nevertheless, there are many insights to be gained from the analysis of entire open source systems, and hopefully this paper has provided some of those insights. It is my hope that, since open source systems make it possible for anyone to analyze them, others will pursue many other lines of analysis to gain further insight into these systems.
This was not as easy as it sounds; each step is described below. Some steps I describe in some detail, because it's sometimes hard to find the necessary information even when the actual steps are easy. Hopefully, this detail will make it easier for others to do similar activities or to repeat the experiment.
Installing the source code files turned out to be nontrivial. First, I inserted the CD-ROM containing all of the source files (in ``.src.rpm'' format) and installed the packages (files) using:
mount /mnt/cdrom cd /mnt/cdrom/SRPMS rpm -ivh *.src.rpm
This installs ``spec'' files and compressed source files; another rpm command (``rpm -bp'') uses the spec files to uncompress the source files into ``build directories'' (as well as apply any necessary patches). Unfortunately, the rpm tool does not enforce any naming consistency between the package names, the spec names, and the build directory names; for consistency this paper will use the names of the build directories, since all later tools based themselves on the build directories.
I decided to (in general) not count ``old'' versions of software (usually placed there for compatibility reasons), since that would be counting the same software more than once. Thus, the following components were not included: ``compat-binutils'', ``compat-egcs'', ``compat-glib'', ``compat-libs'', ``gtk+10'', ``libc-5.3.12'' (an old C library), ``libxml10'', ``ncurses3'', and ``qt1x''. I also didn't include egcs64-19980921 and netscape-sparc, which simply repeated something on another architecture that was available on the i386 in a different package. I did make one exception. I kept both bash-1.14.7 and bash2, two versions of the shell command processor, instead of only counting bash2. While bash2 is the later version of the shell available in the package, the main shell actually used by the Red Hat distribution was the older version of bash. The rationale for this decision appears to be backwards compatibility for older shell scripts; this is suggested by the Red Hat package documentation in both bash-1.14.7 and bash2. It seemed wrong to not include one of the most fundamental pieces of the system in the count, so I included it. At 47067 lines of code (ignoring duplicates), bash-1.14.7 is one of the smaller components anyway. Not including this older component would not substantively change the results presented here.
There are two directories, krb4-1.0 and krb5-1.1.1, which appear to violate this rule - but don't. krb5-1.1.1 is the build directory created by krb5.spec, which is in turn installed by the source RPM package krb5-1.1.1-9.src.rpm. This build directory contains Kerberos V5, a trusted-third-party authentication system. The source RPM package krb5-1.1.1-9.src.rpm eventually generates the binary RPM files krb5-configs-1.1.1-9, krb5-libs-1.1.1-9, and krb5-devel-1.1.1-9. You might guess that ``krb4-1.0'' is just the older version of Kerberos, but this build directory is created by the spec file krbafs.spec and not just an old version of the code. To quote its description, ``This is the Kerberos to AFS bridging library, built against Kerberos 5. krbafs is a shared library that allows programs to obtain AFS tokens using Kerberos IV credentials, without having to link with official AFS libraries which may not be available for a given platform.'' For this situation, I simply counted both packages, since their purposes are different.
I was then confronted with a fundamental question: should I count software that only works for another architecture? I was using an i86-type system, but some components are only for Alpha or Sparc systems. I decided that I should count them; even if I didn't use the code today, the ability to use these other architectures in the future was of value and certainly required effort to develop.
This caused complications for creating the build directories. If all installed packages fit the architecture, you can install the uncompressed software by typing:
cd /usr/src/redhat/SPECS and typing the command rpm -bp *.specUnfortunately, the rpm tool notes that you're trying to load code for the ``wrong'' architecture, and (at least at the time) there was no simple ``override'' flag. Instead, I had to identify each package as belonging to SPARC or ALPHA, and then use the rpm option --target to forcibly load them. For example, I renamed all sparc-specific SPARC file files to end in ``.sparc'' and could then load them with:
rpm -bp --target sparc-redhat-linux *.spec.sparcThe following spec files were non-i86: (sparc) audioctl, elftoaout, ethtool, prtconf, silo, solemul, sparc32; (alpha) aboot, minlabel, quickstrip. In general, these were tools to aid in supporting some part of the boot process or for using system-specific hardware.
Note that not all packages create build directories. For example, ``anonftp'' is a package that, when installed, sets up an anonymous ftp system. This package doesn't actually install any software; it merely installs a specific configuration of another piece of software (and unsets the configuration when uninstalled). Such packages are not counted at all in this sizing estimate.
In theory, one could just look at the file extensions (.c for C, .py for python), but this is not enough in practice. Some packages reuse extensions if the package doesn't use that kind of file (e.g., the ``.exp'' extension of expect was used by some packages as ``export'' files, and the ``.m'' of objective-C was used by some packages for module information extracted from C code). Some files don't have extensions, particularly scripts. And finally, files automatically generated by another program should not be counted, since I wished to use the results to estimate effort.
I ended up writing a program of over 600 lines of Perl to perform this identification, which used a number of heuristics to categorize each file into categories. There is a category for each language, plus the categories non-programs, unknown (useful for scanning for problems), automatically generated program files, duplicate files (whose file contents duplicated other files), and zero-length files.
The program first checked for well-known extensions (such as .gif) that cannot be program files, and for a number of common generated filenames. It then peeked at the first line for "#!" followed by a legal script name. If that didn't work, it used the extension to try to determine the category. For a number of languages, the extension was not reliable, so for those languages the categorization program examined the file contents and used a set of heuristics to determine if the file actually belonged that category. If all else failed, the file was placed in the ``unknown'' category for later analysis. I later looked at the ``unknown'' items, checking the common extensions to ensure I had not missed any common types of code.
One complicating factor was that I wished to separate C, C++, and objective-C code, but a header file ending with ``.h'' or ``.hpp'' file could be any of them. I developed a number of heuristics to determine, for each file, what language it belonged to. For example, if a build directory has exactly one of these languages, determining the correct category for header files is easy. Similarly, if there is exactly one of these in the directory with the header file, it is presumed to be that kind. Finally, a header file with the keyword ``class'' is almost certainly not a C header file, but a C++ header file.
Detecting automatically generated files was not easy, and it's quite conceivable I missed a number of them. The first 15 lines were examined, to determine if any of them included at the beginning of the line (after spaces and possible comment markers) one of the following phrases: ``generated automatically'', ``automatically generated'', ``this is a generated file'', ``generated with the (something) utility'', or ``do not edit''. A number of filename conventions were used, too. For example, any ``configure'' file is presumed to be automatically generated if there's a ``configure.in'' file in the same directory.
To eliminate duplicates, the program kept md5 checksums of each program file. Any given md5 checksum would only be counted once. Build directories were processed alphabetically, so this meant that if the same file content was in both directories ``a'' and ``b'', it would be counted only once as being part of ``a''. Thus, some packages with names later in the alphabet may appear smaller than would make sense at first glance.
It's important to note that different rules could be used to ``count'' lines of code. Some kinds of code were intentionally excluded from the count. Many RPM packages include a number of shell commands used to install and uninstall software; the estimate in this paper does not include the code in RPM packages. This estimate also does not include the code in Makefiles (which can be substantive). In both cases, the code in these cases is often cut and pasted from other similar files, so counting such code would probably overstate the actual development effort. In addition, Makefiles are often automatically generated.
On the other hand, this estimate does include some code that others might not count. This estimate includes test code included with the package, which isn't visible directly to users (other than hopefully higher quality of the executable program). It also includes code not used in this particular system, such as code for other architectures and OS's, bindings for languages not compiled into the binaries, and compilation-time options not chosen. I decided to include such code for two reasons. First, this code is validly represents the effort to build each component. Second, it does represent indirect value to the user, because the user can later use those components in other circumstances even if the user doesn't choose to do so by default.
So, after the work of categorizing the files, the following categories of files were created for each build directory (common extensions are shown in parentheses, and the name used in the data tables below are shown in brackets):
Note that we're counting Scheme as a dialect of LISP, and Expect is being counted separately from TCL. The command line shells Bourne shell, the Bourne-again shell (bash), and the K shell are all counted together as ``shell'', but the C shell (csh and tcsh) is counted separately.
I originally tried to use USC's ``CodeCount'' tools to count the code. Unfortunately, this turned out to be buggy and did not handle most of the languages used in the system, so I eventually abandoned it for this task and wrote my own tools. Those who wish to use this tool are welcome to do so; you can learn more from its web site at http://sunset.usc.edu/research/CODECOUNT.
I did manage to use the CodeCount to compute the logical source lines of code for the C portions of the linux kernel. This came out to be 673,627 logical source lines of code, compared to the 1,462,165 lines of physical code (again, this ignores files with duplicate contents).
Since there were a large number of languages to count, I used the ``physical lines of code'' definition. In this definition, a line of code is a line (ending with newline or end-of-file) with at least one non-comment non-whitespace character. These are known as ``non-comment non-blank'' lines. If a line only had whitespace (tabs and spaces) it was not counted, even if it was in the middle of a data value (e.g., a multiline string). It is much easier to write programs to measure this value than to measure the ``logical'' lines of code, and this measure can be easily applied to widely different languages. Since I had to process a large number of different languages, it made sense to choose the measure that is easier to obtain.
Park  presents a framework of issues to be decided when trying to count code. Using Park's framework, here is how code was counted in this paper:
Park includes in his paper a ``basic definition'' of physical lines of code, defined using his framework. I adhered to Park's definition unless (1) it was impossible in my technique to do so, or (2) it would appear to make the result inappropriate for use in cost estimation (using COCOMO). COCOMO states that source code:
``includes all program instructions created by project personnel and processed into machine code by some combination of preprocessors, compilers, and assemblers. It excludes comment cards and unmodified utility software. It includes job control language, format statements, and data declarations. Instructions are defined as lines of code.''
In summary, though in general I followed Park's definition, I didn't follow Park's ``basic definition'' in the following ways:
One annoying problem was that one file wasn't syntactically correct and it affected the count. File /usr/src/redhat/BUILD/cdrecord-1.8/mkiso had an #ifdef not taken, and the road not taken had a missing double-quote mark before the word ``cannot'':
#ifdef USE_LIBSCHILY comerr(Cannot open '%s'.\n", filename); #endif perror ("fopen"); exit (1); #endifI solved this by hand-patching the source code (for purposes of counting). There were also some files with intentionally erroneous code (e.g., compiler error tests), but these did not impact the SLOC count.
Several languages turn out to be non-trivial to count:
Although their values are not used in estimating effort, I also counted the number of files; summaries of these values are included in appendix B.
Since the linux kernel was the largest single component, and I had questions about the various inconsistencies in the ``Halloween'' documents, I made additional measures of the Linux kernel.
Basic COCOMO is designed to estimate the time from product design (after plans and requirements have been developed) through detailed design, code, unit test, and integration testing. Note that plans and requirement development are not included. COCOMO is designed to include management overhead and the creation of documentation (e.g., user manuals) as well as the code itself. Again, see Boehm  for a more detailed description of the model's assumptions.
In the basic COCOMO model, estimated man-months of effort, design through test, equals 2.4*(KSLOC)^1.05, where KSLOC is the total physical SLOC divided by 1000.
I assumed that each package was built completely independently and that there were no efforts necessary for integration not represented in the code itself. This almost certainly underestimates the true costs, but for most packages it's actually true (many packages don't interact with each other at all). I wished to underestimate (instead of overestimate) the effort and costs, and having no better model, I assumed the simplest possible integration effort. This meant that I applied the model to each component, then summed the results, as opposed to applying the model once to the grand total of all software.
Note that the only input to this model is source lines of code, so some factors simply aren't captured. For example, creating some kinds of data (such as fonts) can be very time-consuming, but this isn't directly captured by this model. Some programs are intentionally designed to be data-driven, that is, they're designed as small programs which are driven by specialized data. Again, this data may be as complex to develop as code, but this is not counted.
Another example of uncaptured factors is the difficulty of writing kernel code. It's generally acknowledged that writing kernel-level code is more difficult than most other kinds of code, because this kind of code is subject to a subtle timing and race conditions, hardware interactions, a small stack, and none of the normal error protections. In this paper I do not attempt to account for this. You could try to use the Intermediate COCOMO model to try to account for this, but again this requires knowledge of other factors that can only be guessed at. Again, the effort estimation probably significantly underestimates the actual effort represented here.
It's worth noting that there is an update to COCOMO, COCOMO II. However, COCOMO II requires as its input logical (not physical) SLOC, and since this measure is much harder to obtain, I did not pursue it for this paper. More information about COCOMO II is available at the web site http://sunset.usc.edu/research/COCOMOII/index.html. A nice overview paper where you can learn more about software metrics is Masse .
I assumed that an average U.S. programmer/analyst salary in the year 2000 was $56,286 per year; this value was from the ComputerWorld, September 4, 2000's Salary Survey, Overhead is much harder to estimate; I did not find a definitive source for information on overheads. After informal discussions with several cost analysts, I determined that an overhead of 2.4 would be representative of the overhead sustained by a typical software development company. Should you diagree with these figures, I've provided all the information necessary to recalculate your own cost figures; just start with the effort estimates and recalculate cost yourself.
Remember that duplicate files are only counted once, with the build directory ``first in ASCII sort order'' receiving any duplicates (to break ties). As a result, some build directories have a smaller number than might at first make sense. For example, the ``kudzu'' build directory does contain code, but all of it is also contained in the ``Xconfigurator'' build directory.. and since that directory sorts first, the kudzu package is considered to have ``no code''.
The columns are SLOC (total physical source lines of code), Directory (the name of the build directory, usually the same or similar to the package name), and SLOC-by-Language (Sorted). This last column lists languages by name and the number of SLOC in that language; zeros are not shown, and the list is sorted from largest to smallest in that build directory. Similarly, the directories are sorted from largest to smallest total SLOC.
SLOC Directory SLOC-by-Language (Sorted) 1526722 linux ansic=1462165,asm=59574,sh=2860,perl=950,tcl=414, yacc=324,lex=230,awk=133,sed=72 1291745 XFree86-3.3.6 ansic=1246420,asm=14913,sh=13433,tcl=8362,cpp=4358, yacc=2710,perl=711,awk=393,lex=383,sed=57,csh=5 720112 egcs-1.1.2 ansic=598682,cpp=75206,sh=14307,asm=11462,yacc=7988, lisp=7252,exp=2887,fortran=1515,objc=482,sed=313,perl=18 652087 gdb-19991004 ansic=587542,exp=37737,sh=9630,cpp=6735,asm=4139, yacc=4117,lisp=1820,sed=220,awk=142,fortran=5 625073 emacs-20.5 lisp=453647,ansic=169624,perl=884,sh=652,asm=253, csh=9,sed=4 467120 binutils-220.127.116.11.22 ansic=407352,asm=27575,exp=12265,sh=7398,yacc=5606, cpp=4454,lex=1479,sed=557,lisp=394,awk=24,perl=16 415026 glibc-2.1.3 ansic=378753,asm=30644,sh=2520,cpp=1704,awk=910, perl=464,sed=16,csh=15 327021 tcltk-8.0.5 ansic=240093,tcl=71947,sh=8531,exp=5150,yacc=762, awk=273,perl=265 247026 postgresql-6.5.3 ansic=207735,yacc=10718,java=8835,tcl=7709,sh=7399, lex=1642,perl=1206,python=959,cpp=746,asm=70,csh=5,sed=2 235702 gimp-1.0.4 ansic=225211,lisp=8497,sh=1994 231072 Mesa ansic=195796,cpp=17717,asm=13467,sh=4092 222220 krb5-1.1.1 ansic=192822,exp=19364,sh=4829,yacc=2476,perl=1528, awk=393,python=348,lex=190,csh=147,sed=123 206237 perl5.005_03 perl=94712,ansic=89366,sh=15654,lisp=5584,yacc=921 205082 qt-2.1.0-beta1 cpp=180866,ansic=20513,yacc=2284,sh=538,lex=464, perl=417 200628 Python-1.5.2 python=100935,ansic=96323,lisp=2353,sh=673,perl=342, sed=2 199982 gs5.50 ansic=195491,cpp=2266,asm=968,sh=751,lisp=405,perl=101 193916 teTeX-1.0 ansic=166041,sh=10263,cpp=9407,perl=3795,pascal=1546, yacc=1507,awk=522,lex=323,sed=297,asm=139,csh=47,lisp=29 155035 bind-8.2.2_P5 ansic=131946,sh=10068,perl=7607,yacc=2231,cpp=1360, csh=848,awk=753,lex=222 140130 AfterStep-APPS-20000124 ansic=135806,sh=3340,cpp=741,perl=243 138931 kdebase cpp=113971,ansic=23016,perl=1326,sh=618 138118 gtk+-1.2.6 ansic=137006,perl=479,sh=352,awk=274,lisp=7 138024 gated-3-5-11 ansic=126846,yacc=7799,sh=1554,lex=877,awk=666,csh=235, sed=35,lisp=12 133193 kaffe-1.0.5 java=65275,ansic=62125,cpp=3923,perl=972,sh=814, asm=84 131372 jade-1.2.1 cpp=120611,ansic=8228,sh=2150,perl=378,sed=5 128672 gnome-libs-1.0.55 ansic=125373,sh=2178,perl=667,awk=277,lisp=177 127536 pine4.21 ansic=126678,sh=766,csh=62,perl=30 121878 ImageMagick-4.2.9 ansic=99383,sh=11143,cpp=8870,perl=2024,tcl=458 119613 lynx2-8-3 ansic=117385,sh=1860,perl=340,csh=28 116951 mc-4.5.42 ansic=114406,sh=1996,perl=345,awk=148,csh=56 116615 gnumeric-0.48 ansic=115592,yacc=600,lisp=191,sh=142,perl=67,python=23 113272 xlispstat-3-52-17 ansic=91484,lisp=21769,sh=18,csh=1 113241 vim-5.6 ansic=111724,awk=683,sh=469,perl=359,csh=6 109824 php-3.0.15 ansic=105901,yacc=1887,sh=1381,perl=537,awk=90,cpp=28 104032 linuxconf-1.17r2 cpp=93139,perl=4570,sh=2984,java=2741,ansic=598 102674 libgr-2.0.13 ansic=99647,sh=2438,csh=589 100951 lam-6.3.1 ansic=86177,cpp=10569,sh=3677,perl=322,fortran=187, csh=19 99066 krb4-1.0 ansic=84077,asm=5163,cpp=3775,perl=2508,sh=1765, yacc=1509,lex=236,awk=33 94637 xlockmore-4.15 ansic=89816,cpp=1987,tcl=1541,sh=859,java=285,perl=149 93940 kdenetwork cpp=80075,ansic=7422,perl=6260,sh=134,tcl=49 92964 samba-2.0.6 ansic=88308,sh=3557,perl=831,awk=158,csh=110 91213 anaconda-6.2.2 ansic=74303,python=13657,sh=1583,yacc=810,lex=732, perl=128 89959 xscreensaver-3.23 ansic=88488,perl=1070,sh=401 88128 cvs-1.10.7 ansic=68303,sh=17909,perl=902,yacc=826,csh=181,lisp=7 87940 isdn4k-utils ansic=78752,perl=3369,sh=3089,cpp=2708,tcl=22 85383 xpdf-0.90 cpp=60427,ansic=21400,sh=3556 81719 inn-2.2.2 ansic=62403,perl=10485,sh=5465,awk=1567,yacc=1547, lex=249,tcl=3 80343 kdelibs cpp=71217,perl=5075,ansic=3660,yacc=240,lex=116, sh=35 79997 WindowMaker-0.61.1 ansic=77924,sh=1483,perl=371,lisp=219 78787 extace-1.2.15 ansic=66571,sh=9322,perl=2894 77873 apache_1.3.12 ansic=69191,sh=6781,perl=1846,cpp=55 75257 xpilot-4.1.0 ansic=68669,tcl=3479,cpp=1896,sh=1145,perl=68 73817 w3c-libwww-5.2.8 ansic=64754,sh=4678,cpp=3181,perl=1204 72726 ucd-snmp-4.1.1 ansic=64411,perl=5558,sh=2757 72425 gnome-core-1.0.55 ansic=72230,perl=141,sh=54 71810 jikes cpp=71452,java=358 70260 groff-1.15 cpp=59453,ansic=5276,yacc=2957,asm=1866,perl=397, sh=265,sed=46 69265 fvwm-2.2.4 ansic=63496,cpp=2463,perl=1835,sh=723,yacc=596,lex=152 69246 linux-86 ansic=63328,asm=5276,sh=642 68997 blt2.4g ansic=58630,tcl=10215,sh=152 68884 squid-2.3.STABLE1 ansic=66305,sh=1570,perl=1009 68560 bash-2.03 ansic=56758,sh=7264,yacc=2808,perl=1730 68453 kdegraphics cpp=34208,ansic=29347,sh=4898 65722 xntp3-5.93 ansic=60190,perl=3633,sh=1445,awk=417,asm=37 62922 ppp-2.3.11 ansic=61756,sh=996,exp=82,perl=44,csh=44 62137 sgml-tools-1.0.9 cpp=38543,ansic=19185,perl=2866,lex=560,sh=532, lisp=309,awk=142 61688 imap-4.7 ansic=61628,sh=60 61324 ncurses-5.0 ansic=45856,ada=8217,cpp=3720,sh=2822,awk=506,perl=103, sed=100 60429 kdesupport ansic=42421,cpp=17810,sh=173,awk=13,csh=12 60302 openldap-1.2.9 ansic=58078,sh=1393,perl=630,python=201 57217 xfig.3.2.3-beta-1 ansic=57212,csh=5 56093 lsof_4.47 ansic=50268,sh=4753,perl=856,awk=214,asm=2 55667 uucp-1.06.1 ansic=52078,sh=3400,perl=189 54935 gnupg-1.0.1 ansic=48884,asm=4586,sh=1465 54603 glade-0.5.5 ansic=49545,sh=5058 54431 svgalib-1.4.1 ansic=53725,asm=630,perl=54,sh=22 53141 AfterStep-1.8.0 ansic=50898,perl=1168,sh=842,cpp=233 52808 kdeutils cpp=41365,ansic=9693,sh=1434,awk=311,sed=5 52574 nmh-1.0.3 ansic=50698,sh=1785,awk=74,sed=17 51813 freetype-1.3.1 ansic=48929,sh=2467,cpp=351,csh=53,perl=13 51592 enlightenment-0.15.5 ansic=51569,sh=23 50970 cdrecord-1.8 ansic=48595,sh=2177,perl=194,sed=4 49370 tin-1.4.2 ansic=47763,sh=908,yacc=699 49325 imlib-1.9.7 ansic=49260,sh=65 48223 kdemultimedia ansic=24248,cpp=22275,tcl=1004,sh=621,perl=73,awk=2 47067 bash-1.14.7 ansic=41654,sh=3140,yacc=2197,asm=48,awk=28 46312 tcsh-6.09.00 ansic=43544,sh=921,lisp=669,perl=593,csh=585 46159 unzip-5.40 ansic=40977,cpp=3778,asm=1271,sh=133 45811 mutt-1.0.1 ansic=45574,sh=237 45589 am-utils-6.0.3 ansic=33389,sh=8950,perl=2421,lex=454,yacc=375 45485 guile-1.3 ansic=38823,lisp=4626,asm=1514,sh=310,awk=162,csh=50 45378 gnuplot-3.7.1 ansic=43276,lisp=661,asm=539,objc=387,csh=297,perl=138, sh=80 44323 mgetty-1.1.21 ansic=33757,perl=5889,sh=3638,tcl=756,lisp=283 42880 sendmail-8.9.3 ansic=40364,perl=1737,sh=779 42746 elm2.5.3 ansic=32931,sh=9774,awk=41 41388 p2c-1.22 ansic=38788,pascal=2499,perl=101 41205 gnome-games-1.0.51 ansic=31191,lisp=6966,cpp=3048 39861 rpm-3.0.4 ansic=36994,sh=1505,perl=1355,python=7 39160 util-linux-2.10f ansic=38627,sh=351,perl=65,csh=62,sed=55 38927 xmms-1.0.1 ansic=38366,asm=398,sh=163 38548 ORBit-0.5.0 ansic=35656,yacc=1750,sh=776,lex=366 38453 zsh-3.0.7 ansic=36208,sh=1763,perl=331,awk=145,sed=6 37515 ircii-4.4 ansic=36647,sh=852,lex=16 37360 tiff-v3.5.4 ansic=32734,sh=4054,cpp=572 36338 textutils-2.0a ansic=18949,sh=16111,perl=1218,sed=60 36243 exmh-2.1.1 tcl=35844,perl=316,sh=49,exp=34 36239 x11amp-0.9-alpha3 ansic=31686,sh=4200,asm=353 35812 xloadimage.4.1 ansic=35705,sh=107 35554 zip-2.3 ansic=32108,asm=3446 35397 gtk-engines-0.10 ansic=20636,sh=14761 35136 php-2.0.1 ansic=33991,sh=1056,awk=89 34882 pmake ansic=34599,sh=184,awk=58,sed=41 34772 xpuzzles-5.4.1 ansic=34772 34768 fileutils-4.0p ansic=31324,sh=2042,yacc=841,perl=561 33203 strace-4.2 ansic=30891,sh=1988,perl=280,lisp=44 32767 trn-3.6 ansic=25264,sh=6843,yacc=660 32277 pilot-link.0.9.3 ansic=26513,java=2162,cpp=1689,perl=971,yacc=660, python=268,tcl=14 31994 korganizer cpp=23402,ansic=5884,yacc=2271,perl=375,lex=61,sh=1 31174 ncftp-3.0beta21 ansic=30347,cpp=595,sh=232 30438 gnome-pim-1.0.55 ansic=28665,yacc=1773 30122 scheme-3.2 lisp=19483,ansic=10515,sh=124 30061 tcpdump-3.4 ansic=29208,yacc=236,sh=211,lex=206,awk=184,csh=16 29730 screen-3.9.5 ansic=28156,sh=1574 29315 jed ansic=29315 29091 xchat-1.4.0 ansic=28894,perl=121,python=53,sh=23 28897 ncpfs-18.104.22.168 ansic=28689,sh=182,tcl=26 28449 slrn-0.9.6.2 ansic=28438,sh=11 28261 xfishtank-2.1tp ansic=28261 28186 texinfo-4.0 ansic=26404,sh=841,awk=451,perl=256,lisp=213,sed=21 28169 e2fsprogs-1.18 ansic=27250,awk=437,sh=339,sed=121,perl=22 28118 slang ansic=28118 27860 kdegames cpp=27507,ansic=340,sh=13 27117 librep-0.10 ansic=19381,lisp=5385,sh=2351 27040 mikmod-3.1.6 ansic=26975,sh=55,awk=10 27022 x3270-3.1.1 ansic=26456,sh=478,exp=88 26673 lout-3.17 ansic=26673 26608 Xaw3d-1.3 ansic=26235,yacc=247,lex=126 26363 gawk-3.0.4 ansic=19871,awk=2519,yacc=2046,sh=1927 26146 libxml-1.8.6 ansic=26069,sh=77 25994 xrn-9.02 ansic=24686,yacc=888,sh=249,lex=92,perl=35,awk=31, csh=13 25915 gv-3.5.8 ansic=25821,sh=94 25479 xpaint ansic=25456,sh=23 25236 shadow-19990827 ansic=23464,sh=883,yacc=856,perl=33 24910 kdeadmin cpp=19919,sh=3936,perl=1055 24773 pdksh-5.2.14 ansic=23599,perl=945,sh=189,sed=40 24583 gmp-2.0.2 ansic=17888,asm=5252,sh=1443 24387 mars_nwe ansic=24158,sh=229 24270 gnome-python-1.0.51 python=14331,ansic=9791,sh=148 23838 kterm-6.2.0 ansic=23838 23666 enscript-1.6.1 ansic=22365,lex=429,perl=308,sh=291,yacc=164,lisp=109 22373 sawmill-0.24 ansic=11038,lisp=8172,sh=3163 22279 make-3.78.1 ansic=19287,sh=2029,perl=963 22011 libpng-1.0.5 ansic=22011 21593 xboard-4.0.5 ansic=20640,lex=904,sh=41,csh=5,sed=3 21010 netkit-telnet-0.16 ansic=14796,cpp=6214 20433 pam-0.72 ansic=18936,yacc=634,sh=482,perl=321,lex=60 20125 ical-2.2 cpp=12651,tcl=6763,sh=624,perl=60,ansic=27 20078 gd1.3 ansic=19946,perl=132 19971 wu-ftpd-2.6.0 ansic=17572,yacc=1774,sh=421,perl=204 19500 gnome-utils-1.0.50 ansic=18099,yacc=824,lisp=577 19065 joe ansic=18841,asm=224 18885 X11R6-contrib-3.3.2 ansic=18616,lex=161,yacc=97,sh=11 18835 glib-1.2.6 ansic=18702,sh=133 18151 git-4.3.19 ansic=16166,sh=1985 18020 xboing ansic=18006,sh=14 17939 sh-utils-2.0 ansic=13366,sh=3027,yacc=871,perl=675 17765 mtools-3.9.6 ansic=16155,sh=1602,sed=8 17750 gettext-0.10.35 ansic=13414,lisp=2030,sh=1983,yacc=261,perl=53,sed=9 17682 bc-1.05 ansic=9186,sh=7236,yacc=967,lex=293 17271 fetchmail-5.3.1 ansic=13441,python=1490,sh=1246,yacc=411,perl=321, lex=238,awk=124 17259 sox-12.16 ansic=16659,sh=600 16785 control-center-1.0.51 ansic=16659,sh=126 16266 dhcp-2.0 ansic=15328,sh=938 15967 SVGATextMode-1.9-src ansic=15079,yacc=340,sh=294,lex=227,sed=15, asm=12 15868 kpilot-3.1b9 cpp=8613,ansic=5640,yacc=1615 15851 taper-6.9a ansic=15851 15819 mpg123-0.59r ansic=14900,asm=919 15691 transfig.3.2.1 ansic=15643,sh=38,csh=10 15638 mod_perl-1.21 perl=10278,ansic=5124,sh=236 15522 console-tools-0.3.3 ansic=13335,yacc=986,sh=800,lex=291,perl=110 15456 rpm2html-1.2 ansic=15334,perl=122 15143 gnotepad+-1.1.4 ansic=15143 15108 GXedit1.23 ansic=15019,sh=89 15087 mm2.7 ansic=8044,csh=6924,sh=119 14941 readline-2.2.1 ansic=11375,sh=1890,perl=1676 14912 ispell-3.1 ansic=8380,lisp=3372,yacc=1712,cpp=585,objc=385, csh=221,sh=157,perl=85,sed=15 14871 gnuchess-4.0.pl80 ansic=14584,sh=258,csh=29 14774 flex-2.5.4 ansic=13011,lex=1045,yacc=605,awk=72,sh=29,sed=12 14587 multimedia ansic=14577,sh=10 14516 libgtop-1.0.6 ansic=13768,perl=653,sh=64,asm=31 14427 mawk-1.2.2 ansic=12714,yacc=994,awk=629,sh=90 14363 automake-1.4 perl=10622,sh=3337,ansic=404 14350 rsync-2.4.1 ansic=13986,perl=179,sh=126,awk=59 14299 nfs-utils-0.1.6 ansic=14107,sh=165,perl=27 14269 rcs-5.7 ansic=12209,sh=2060 14255 tar-1.13.17 ansic=13014,lisp=592,sh=538,perl=111 14105 wmakerconf-2.1 ansic=13620,perl=348,sh=137 14039 less-346 ansic=14032,awk=7 13779 rxvt-2.6.1 ansic=13779 13586 wget-1.5.3 ansic=13509,perl=54,sh=23 13504 rp3-1.0.7 cpp=10416,ansic=2957,sh=131 13241 iproute2 ansic=12139,sh=1002,perl=100 13100 silo-0.9.8 ansic=10485,asm=2615 12657 macutils ansic=12657 12639 libungif-4.1.0 ansic=12381,sh=204,perl=54 12633 minicom-1.83.0 ansic=12503,sh=130 12593 audiofile-0.1.9 sh=6440,ansic=6153 12463 gnome-objc-1.0.2 objc=12365,sh=86,ansic=12 12313 jpeg-6a ansic=12313 12124 ypserv-1.3.9 ansic=11622,sh=460,perl=42 11790 lrzsz-0.12.20 ansic=9512,sh=1263,exp=1015 11775 modutils-2.3.9 ansic=9309,sh=1620,lex=484,yacc=362 11721 enlightenment-conf-0.15 ansic=6232,sh=5489 11633 net-tools-1.54 ansic=11531,sh=102 11404 findutils-4.1 ansic=11160,sh=173,exp=71 11299 xmorph-1999dec12 ansic=10783,tcl=516 10958 kpackage-1.3.10 cpp=8863,sh=1852,ansic=124,perl=119 10914 diffutils-2.7 ansic=10914 10404 gnorpm-0.9 ansic=10404 10271 gqview-0.7.0 ansic=10271 10267 libPropList-0.9.1 sh=5974,ansic=3982,lex=172,yacc=139 10187 dump-0.4b15 ansic=9422,sh=760,sed=5 10088 piranha ansic=10048,sh=40 10013 grep-2.4 ansic=9852,sh=103,awk=49,sed=9 9961 procps-2.0.6 ansic=9959,sh=2 9942 xpat2-1.04 ansic=9942 9927 procmail-3.14 ansic=8090,sh=1837 9873 nss_ldap-105 ansic=9784,perl=89 9801 man-1.5h1 ansic=7377,sh=1802,perl=317,awk=305 9741 Xconfigurator-4.3.5 ansic=9578,perl=125,sh=32,python=6 9731 ld.so-1.9.5 ansic=6960,asm=2401,sh=370 9725 gpm-1.18.1 ansic=8107,yacc=1108,lisp=221,sh=209,awk=74,sed=6 9699 bison-1.28 ansic=9650,sh=49 9666 ash-linux-0.2 ansic=9445,sh=221 9607 cproto-4.6 ansic=7600,lex=985,yacc=761,sh=261 9551 pwdb-0.61 ansic=9488,sh=63 9465 rdist-6.1.5 ansic=8306,sh=553,yacc=489,perl=117 9263 ctags-3.4 ansic=9240,sh=23 9138 gftp-2.0.6a ansic=9138 8939 mkisofs-1.12b5 ansic=8939 8766 pxe-linux cpp=4463,ansic=3622,asm=681 8572 psgml-1.2.1 lisp=8572 8540 xxgdb-1.12 ansic=8540 8491 gtop-1.0.5 ansic=8151,cpp=340 8356 gedit-0.6.1 ansic=8225,sh=131 8303 dip-3.3.7o ansic=8207,sh=96 7859 libglade-0.11 ansic=5898,sh=1809,python=152 7826 xpm-3.4k ansic=7750,sh=39,cpp=37 7740 sed-3.02 ansic=7301,sed=359,sh=80 7617 cpio-2.4.2 ansic=7598,sh=19 7615 esound-0.2.17 ansic=7387,sh=142,csh=86 7570 sharutils-4.2.1 ansic=5511,perl=1741,sh=318 7427 ed-0.2 ansic=7263,sh=164 7255 lilo ansic=3522,asm=2557,sh=740,perl=433,cpp=3 7227 cdparanoia-III-alpha9.6 ansic=6006,sh=1221 7095 xgammon-0.98 ansic=6506,lex=589 7041 newt-0.50.8 ansic=6526,python=515 7030 ee-0.3.11 ansic=7007,sh=23 6976 aboot-0.5 ansic=6680,asm=296 6968 mailx-8.1.1 ansic=6963,sh=5 6877 lpr ansic=6842,sh=35 6827 gnome-media-1.0.51 ansic=6827 6646 iputils ansic=6646 6611 patch-2.5 ansic=6561,sed=50 6592 xosview-1.7.1 cpp=6205,ansic=367,awk=20 6550 byacc-1.9 ansic=5520,yacc=1030 6496 pidentd-3.0.10 ansic=6475,sh=21 6391 m4-1.4 ansic=5993,lisp=243,sh=155 6306 gzip-1.2.4a ansic=5813,asm=458,sh=24,perl=11 6234 awesfx-0.4.3a ansic=6234 6172 sash-3.4 ansic=6172 6116 lslk ansic=5325,sh=791 6090 joystick-1.2.15 ansic=6086,sh=4 6072 kdoc perl=6010,sh=45,cpp=17 6043 irda-utils-0.9.10 ansic=5697,sh=263,perl=83 6033 sysvinit-2.78 ansic=5256,sh=777 6025 pnm2ppa ansic=5708,sh=317 6021 rpmfind-1.4 ansic=6021 5981 indent-2.2.5 ansic=5958,sh=23 5975 ytalk-3.1 ansic=5975 5960 isapnptools-1.21 ansic=4394,yacc=1383,perl=123,sh=60 5744 gdm-2.0beta2 ansic=5632,sh=112 5594 isdn-config cpp=3058,sh=2228,perl=308 5526 efax-0.9 ansic=4570,sh=956 5383 acct-6.3.2 ansic=5016,cpp=287,sh=80 5115 libtool-1.3.4 sh=3374,ansic=1741 5111 netkit-ftp-0.16 ansic=5111 4996 bzip2-0.9.5d ansic=4996 4895 xcpustate-2.5 ansic=4895 4792 libelf-0.6.4 ansic=3310,sh=1482 4780 make-3.78.1_pvm-0.5 ansic=4780 4542 gpgp-0.4 ansic=4441,sh=101 4430 gperf-2.7 cpp=2947,exp=745,ansic=695,sh=43 4367 aumix-1.30.1 ansic=4095,sh=179,sed=93 4087 zlib-1.1.3 ansic=2815,asm=712,cpp=560 4038 sysklogd-1.3-31 ansic=3741,perl=158,sh=139 4024 rep-gtk-0.8 ansic=2905,lisp=971,sh=148 3962 netkit-timed-0.16 ansic=3962 3929 initscripts-5.00 sh=2035,ansic=1866,csh=28 3896 ltrace-0.3.10 ansic=2986,sh=854,awk=56 3885 phhttpd-0.1.0 ansic=3859,sh=26 3860 xdaliclock-2.18 ansic=3837,sh=23 3855 pciutils-2.1.5 ansic=3800,sh=55 3804 quota-2.00-pre3 ansic=3795,sh=9 3675 dosfstools-2.2 ansic=3675 3654 tcp_wrappers_7.6 ansic=3654 3651 ipchains-1.3.9 ansic=2767,sh=884 3625 autofs-3.1.4 ansic=2862,sh=763 3588 netkit-rsh-0.16 ansic=3588 3438 yp-tools-2.4 ansic=3415,sh=23 3433 dialog-0.6 ansic=2834,perl=349,sh=250 3415 ext2ed-0.1 ansic=3415 3315 gdbm-1.8.0 ansic=3290,cpp=25 3245 ypbind-3.3 ansic=1793,sh=1452 3219 playmidi-2.4 ansic=3217,sed=2 3096 xtrojka123 ansic=3087,sh=9 3084 at-3.1.7 ansic=1442,sh=1196,yacc=362,lex=84 3051 dhcpcd-1.3.18-pl3 ansic=2771,sh=280 3012 apmd ansic=2617,sh=395 2883 netkit-base-0.16 ansic=2883 2879 vixie-cron-3.0.1 ansic=2866,sh=13 2835 gkermit-1.0 ansic=2835 2810 kdetoys cpp=2618,ansic=192 2791 xjewel-1.6 ansic=2791 2773 mpage-2.4 ansic=2704,sh=69 2758 autoconf-2.13 sh=2226,perl=283,exp=167,ansic=82 2705 autorun-2.61 sh=1985,cpp=720 2661 cdp-0.33 ansic=2661 2647 file-3.28 ansic=2601,perl=46 2645 libghttp-1.0.4 ansic=2645 2631 getty_ps-2.0.7j ansic=2631 2597 pythonlib-1.23 python=2597 2580 magicdev-0.2.7 ansic=2580 2531 gnome-kerberos-0.2 ansic=2531 2490 sndconfig-0.43 ansic=2490 2486 bug-buddy-0.7 ansic=2486 2459 usermode-1.20 ansic=2459 2455 fnlib-0.4 ansic=2432,sh=23 2447 sliplogin-2.1.1 ansic=2256,sh=143,perl=48 2424 raidtools-0.90 ansic=2418,sh=6 2423 netkit-routed-0.16 ansic=2423 2407 nc ansic=1670,sh=737 2324 up2date-1.13 python=2324 2270 memprof-0.3.0 ansic=2270 2268 which-2.9 ansic=1398,sh=870 2200 printtool tcl=2200 2163 gnome-linuxconf-0.25 ansic=2163 2141 unarj-2.43 ansic=2141 2065 units-1.55 ansic=1963,perl=102 2048 netkit-ntalk-0.16 ansic=2048 1987 cracklib,2.7 ansic=1919,perl=46,sh=22 1984 cleanfeed-0.95.7b perl=1984 1977 wmconfig-0.9.8 ansic=1941,sh=36 1941 isicom ansic=1898,sh=43 1883 slocate-2.1 ansic=1802,sh=81 1857 netkit-rusers-0.16 ansic=1857 1856 pump-0.7.8 ansic=1856 1842 cdecl-2.5 ansic=1002,yacc=765,lex=75 1765 fbset-2.1 ansic=1401,yacc=130,lex=121,perl=113 1653 adjtimex-1.9 ansic=1653 1634 netcfg-2.25 python=1632,sh=2 1630 psmisc ansic=1624,sh=6 1621 urlview-0.7 ansic=1515,sh=106 1604 fortune-mod-9708 ansic=1604 1531 netkit-tftp-0.16 ansic=1531 1525 logrotate-3.3.2 ansic=1524,sh=1 1473 traceroute-1.4a5 ansic=1436,awk=37 1452 time-1.7 ansic=1395,sh=57 1435 ncompress-4.2.4 ansic=1435 1361 mt-st-0.5b ansic=1361 1290 cxhextris ansic=1290 1280 pam_krb5-1 ansic=1280 1272 bsd-finger-0.16 ansic=1272 1229 hdparm-3.6 ansic=1229 1226 procinfo-17 ansic=1145,perl=81 1194 passwd-0.64.1 ansic=1194 1182 auth_ldap-1.4.0 ansic=1182 1146 prtconf-1.3 ansic=1146 1143 anacron-2.1 ansic=1143 1129 xbill-2.0 cpp=1129 1099 popt-1.4 ansic=1039,sh=60 1088 nag perl=1088 1076 stylesheets-0.13rh perl=888,sh=188 1075 authconfig-3.0.3 ansic=1075 1049 kpppload-1.04 cpp=1044,sh=5 1020 MAKEDEV-2.5.2 sh=1020 1013 trojka ansic=1013 987 xmailbox-2.5 ansic=987 967 netkit-rwho-0.16 ansic=967 953 switchdesk-2.1 ansic=314,perl=287,cpp=233,sh=119 897 portmap_4 ansic=897 874 ldconfig-1999-02-21 ansic=874 844 jpeg-6b sh=844 834 ElectricFence-2.1 ansic=834 830 mouseconfig-4.4 ansic=830 816 rpmlint-0.8 python=813,sh=3 809 kdpms-0.2.8 cpp=809 797 termcap-2.0.8 ansic=797 787 xsysinfo-1.7 ansic=787 770 giftrans-1.12.2 ansic=770 742 setserial-2.15 ansic=742 728 tree-1.2 ansic=728 717 chkconfig-1.1.2 ansic=717 682 lpg perl=682 657 eject-2.0.2 ansic=657 616 diffstat-1.27 ansic=616 592 netscape-4.72 sh=592 585 usernet-1.0.9 ansic=585 549 genromfs-0.3 ansic=549 548 tksysv-1.1 tcl=526,sh=22 537 minlabel-1.2 ansic=537 506 netkit-bootparamd-0.16 ansic=506 497 locale_config-0.2 ansic=497 491 helptool-2.4 perl=288,tcl=203 480 elftoaout-2.2 ansic=480 463 tmpwatch-2.2 ansic=311,sh=152 445 rhs-printfilters-1.63 sh=443,ansic=2 441 audioctl ansic=441 404 control-panel-3.13 ansic=319,tcl=85 368 kbdconfig-22.214.171.124 ansic=368 368 vlock-1.3 ansic=368 367 timetool-2.7.3 tcl=367 347 kernelcfg-0.5 python=341,sh=6 346 timeconfig-3.0.3 ansic=318,sh=28 343 mingetty-0.9.4 ansic=343 343 chkfontpath-1.7 ansic=343 332 ethtool-1.0 ansic=332 314 mkbootdisk-1.2.5 sh=314 302 symlinks-1.2 ansic=302 301 xsri-1.0 ansic=301 294 netkit-rwall-0.16 ansic=294 290 biff+comsat-0.16 ansic=290 288 mkinitrd-2.4.1 sh=288 280 stat-1.5 ansic=280 265 sysreport-1.0 sh=265 261 bdflush-1.5 ansic=202,asm=59 255 ipvsadm-1.1 ansic=255 255 sag-0.6-html perl=255 245 man-pages-1.28 sh=244,sed=1 240 open-1.4 ansic=240 236 xtoolwait-1.2 ansic=236 222 utempter-0.5.2 ansic=222 222 mkkickstart-2.1 sh=222 221 hellas sh=179,perl=42 213 rhmask ansic=213 159 quickstrip-1.1 ansic=159 132 rdate-1.0 ansic=132 131 statserial-1.1 ansic=121,sh=10 107 fwhois-1.00 ansic=107 85 mktemp-1.5 ansic=85 82 modemtool-1.21 python=73,sh=9 67 setup-1.2 ansic=67 56 shaper ansic=56 52 sparc32-1.1 ansic=52 47 intimed-1.10 ansic=47 23 locale-ja-9 sh=23 16 AnotherLevel-1.0.1 sh=16 11 words-2 sh=11 7 trXFree86-2.1.2 tcl=7 0 install-guide-3.2.html (none) 0 caching-nameserver-6.2 (none) 0 XFree86-ISO8859-2-1.0 (none) 0 rootfiles (none) 0 ghostscript-fonts-5.50 (none) 0 kudzu-0.36 (none) 0 wvdial-1.41 (none) 0 mailcap-2.0.6 (none) 0 desktop-backgrounds-1.1 (none) 0 redhat-logos (none) 0 solemul-1.1 (none) 0 dev-2.7.18 (none) 0 urw-fonts-2.0 (none) 0 users-guide-1.0.72 (none) 0 sgml-common-0.1 (none) 0 setup-2.1.8 (none) 0 jadetex (none) 0 gnome-audio-1.0.0 (none) 0 specspo-6.2 (none) 0 gimp-data-extras-1.0.0 (none) 0 docbook-3.1 (none) 0 indexhtml-6.2 (none) ansic: 14218806 (80.55%) cpp: 1326212 (7.51%) lisp: 565861 (3.21%) sh: 469950 (2.66%) perl: 245860 (1.39%) asm: 204634 (1.16%) tcl: 152510 (0.86%) python: 140725 (0.80%) yacc: 97506 (0.55%) java: 79656 (0.45%) exp: 79605 (0.45%) lex: 15334 (0.09%) awk: 14705 (0.08%) objc: 13619 (0.08%) csh: 10803 (0.06%) ada: 8217 (0.05%) pascal: 4045 (0.02%) sed: 2806 (0.02%) fortran: 1707 (0.01%) Total Physical Source Lines of Code (SLOC) = 17652561 Total Estimated Person-Years of Development = 4548.36 Average Programmer Annual Salary = 56286 Overhead Multiplier = 2.4 Total Estimated Cost to Develop = $ 614421924.71
There were 181,679 ordinary files in the build directory. The following are counts of the number of files (not the SLOC) for each language:
ansic: 52088 (71.92%) cpp: 8092 (11.17%) sh: 3381 (4.67%) asm: 1931 (2.67%) perl: 1387 (1.92%) lisp: 1168 (1.61%) java: 1047 (1.45%) python: 997 (1.38%) tcl: 798 (1.10%) exp: 472 (0.65%) awk: 285 (0.39%) objc: 260 (0.36%) sed: 112 (0.15%) yacc: 110 (0.15%) csh: 94 (0.13%) ada: 92 (0.13%) lex: 57 (0.08%) fortran: 50 (0.07%) pascal: 7 (0.01%) Total Number of Source Code Files = 72428
In addition, when counting the number of files (not SLOC), some files were identified as source code files but nevertheless were not counted for other reasons (and thus not included in the file counts above). Of these source code files, 5,820 files were identified as duplicating the contents of another file, 817 files were identified as files that had been automatically generated, and 65 files were identified as zero-length files.
BUILD/linux/Documentation/ 765 BUILD/linux/arch/ 236651 BUILD/linux/configs/ 0 BUILD/linux/drivers/ 876436 BUILD/linux/fs/ 88667 BUILD/linux/ibcs/ 16619 BUILD/linux/include/ 136982 BUILD/linux/init/ 1302 BUILD/linux/ipc/ 1757 BUILD/linux/kernel/ 7436 BUILD/linux/ksymoops-0.7c/ 3271 BUILD/linux/lib/ 1300 BUILD/linux/mm/ 6771 BUILD/linux/net/ 105549 BUILD/linux/pcmcia-cs-3.1.8/ 34851 BUILD/linux/scripts/ 8357
I separately ran the CodeCount tools on the entire linux operating system kernel. Using the CodeCount definition of C logical lines of code, CodeCount determined that this version of the linux kernel included 673,627 logical SLOC in C. This is obviously much smaller than the 1,462,165 of physical SLOC in C, or the 1,526,722 SLOC when all languages are combined for Linux.
However, this included non-i86 code. To make a more reasonable comparison with the Halloween documents, I needed to ignore non-i386 code.
First, I looked at the linux/arch directory, which contained architecture-specific code. This directory had the following subdirectories (architectures): alpha, arm, i386, m68k, mips, ppc, s390, sparc, sparc64. I then computed the total for all of ``arch'', which was 236651 SLOC, and subtracted out linux/arch/i386 code, which totalled to 26178 SLOC; this gave me a total of non-i386 code in linux/arc as 210473 physical SLOC. I then looked through the ``drivers'' directory to see if there were sets of drivers which were non-i386. I identified the following directories, with the SLOC totals as shown:
linux/drivers/sbus/ 22354 linux/drivers/macintosh/ 6000 linux/drivers/sgi/ 4402 linux/drivers/fc4/ 3167 linux/drivers/nubus/ 421 linux/drivers/acorn/ 11850 linux/drivers/s390/ 8653 Driver Total: 56847Thus, I had a grand total on non-i86 code (including drivers and architecture-specific code) as 267320 physical SLOC. This is, of course, another approximation, since there's certainly other architecture-specific lines, but I believe that is most of it. Running the CodeCount tool on just the C code, once these architectural and driver directories are removed, reveals a logical SLOC of 570,039 of C code.
Red Hat Linux 6.2, CD-ROM #1, file RedHat/base/comps, defines the ``base'' (minimum) Red Hat Linux 6.2 installation as a set of packages. The following are the build directories corresponding to this base (minimum) installation, along with the SLOC counts (as shown above). Note that this creates a text-only system:
Component SLOC anacron-2.1 1143 apmd 3012 ash-linux-0.2 9666 at-3.1.7 3084 authconfig-3.0.3 1075 bash-1.14.7 47067 bc-1.05 17682 bdflush-1.5 261 binutils-126.96.36.199.22 467120 bzip2-0.9.5d 4996 chkconfig-1.1.2 717 console-tools-0.3.3 15522 cpio-2.4.2 7617 cracklib,2.7 1987 dev-2.7.18 0 diffutils-2.7 10914 dump-0.4b15 10187 e2fsprogs-1.18 28169 ed-0.2 7427 egcs-1.1.2 720112 eject-2.0.2 657 file-3.28 2647 fileutils-4.0p 34768 findutils-4.1 11404 gawk-3.0.4 26363 gd1.3 20078 gdbm-1.8.0 3315 getty_ps-2.0.7j 2631 glibc-2.1.3 415026 gmp-2.0.2 24583 gnupg-1.0.1 54935 gpm-1.18.1 9725 grep-2.4 10013 groff-1.15 70260 gzip-1.2.4a 6306 hdparm-3.6 1229 initscripts-5.00 3929 isapnptools-1.21 5960 kbdconfig-188.8.131.52 368 kernelcfg-0.5 347 kudzu-0.36 0 ldconfig-1999-02-21 874 ld.so-1.9.5 9731 less-346 14039 lilo 7255 linuxconf-1.17r2 104032 logrotate-3.3.2 1525 mailcap-2.0.6 0 mailx-8.1.1 6968 MAKEDEV-2.5.2 1020 man-1.5h1 9801 mingetty-0.9.4 343 mkbootdisk-1.2.5 314 mkinitrd-2.4.1 288 mktemp-1.5 85 modutils-2.3.9 11775 mouseconfig-4.4 830 mt-st-0.5b 1361 ncompress-4.2.4 1435 ncurses-5.0 61324 net-tools-1.54 11633 newt-0.50.8 7041 pam-0.72 20433 passwd-0.64.1 1194 pciutils-2.1.5 3855 popt-1.4 1099 procmail-3.14 9927 procps-2.0.6 9961 psmisc 1630 pump-0.7.8 1856 pwdb-0.61 9551 quota-2.00-pre3 3804 raidtools-0.90 2424 readline-2.2.1 14941 redhat-logos 0 rootfiles 0 rpm-3.0.4 39861 sash-3.4 6172 sed-3.02 7740 sendmail-8.9.3 42880 setserial-2.15 742 setup-1.2 67 setup-2.1.8 0 shadow-19990827 25236 sh-utils-2.0 17939 slang 28118 slocate-2.1 1883 stat-1.5 280 sysklogd-1.3-31 4038 sysvinit-2.78 6033 tar-1.13.17 14255 termcap-2.0.8 797 texinfo-4.0 28186 textutils-2.0a 36338 time-1.7 1452 timeconfig-3.0.3 346 tmpwatch-2.2 463 utempter-0.5.2 222 util-linux-2.10f 39160 vim-5.6 113241 vixie-cron-3.0.1 2879 which-2.9 2268 zlib-1.1.3 4087
Thus, the contents of the build directories corresponding to the ``base'' (minimum) installation totals to 2,819,334 SLOC.
A few notes are in order about this build directory total:
Many people prefer some sort of graphical interface; here is a minimal configuration of a graphical system, adding the X server, a window manager, and a few tools:
Adding these numbers together, we now have a total of 4,208,970 SLOC for a ``minimal graphical system.'' Many people would want to add more components. For example, this doesn't include a graphical toolkit (necessary for running most graphical applications). We could add gtk+-1.2.6 (a toolkit needed for running GTK+ based applications), adding 138,118 SLOC. This would now total 4,347,088 for a ``basic graphical system,'' one able to run basic GTK+ applications.
Let's add a web server to the mix. Adding apache_1.3.12 adds only 77,873 SLOC. We now have 4,424,961 physical SLOC for a basic graphical system plus a web server.
We could then add a graphical desktop environment, but there are so many different options and possibilities that trying to identify a ``minimal'' system is hard to do without knowing the specific uses intended for the system. Red Hat defines a standard ``GNOME'' and ``KDE'' desktop, but these are intended to be highly functional (not ``minimal''). Thus, we'll stop here, with a total of 2.8 million physical SLOC for a minimal text-based system, and total of 4.4 million physical SLOC for a basic graphical system plus a web server.
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This paper is (C) Copyright 2000 David A. Wheeler. All rights reserved. You may download and print it for your own personal use, and of course you may link to it. When referring to the paper, please refer to it as ``Estimating GNU/Linux's Size'' by David A. Wheeler, located at http://www.dwheeler.com/sloc. Please give credit if you refer to any of its techniques or results.