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The GNU/Linux Platform and Freedom RespectingSoftware for Economists

A. Talha Yalta Riccardo LucchettiTOBB University of Universita Politecnica

Economics and Technology delle Marche, Ancona

October, 2007

Abstract

The GNU/Linux operating system is rapidly gaining ground as an attractivealternative to the proprietary platforms particularly in government agencies andacademic institutions. Here, we supply an assessment of this resource from theperspective of econometricians, discuss its benefits and disadvantages along with abasic overview of some of the popular free/libre and open source programs hostedby this platform for conducting research in economics.

1 Introduction

GNU/Linux (pronounced guh-noo / lin-ux) is a Unix like, free and open source computeroperating system, which provides an excellent platform for conducting research in eco-nomics. During the last few years, GNU/Linux has reached a level of maturity whereit is now considered to be at the same level and in some ways superior to the leadingcommercial alternative from Microsoft Corporation. While adoption is still in its early

stages,1

GNU/Linux is quickly coming into widespread use, particularly in governmentagencies and academic institutions. Today, many economics departments around theworld are using it for performing everyday tasks as well as for carrying out large scaleresearch projects.

Correspondence to: TOBB University of Economics and Technology, Sogutozu Caddesi No:43,Sogutozu, 06560, Ankara, Turkey E-mail: [email protected]

1Estimating the total number of GNU/Linux users is difficult. Software companies know how manylicenses they have issued. On the other hand, when it comes to Free Software, no-one knows howmany copies have been produced. A very informal attempt by the authors to measure popularity ofthis platform using the Google search engine on 4-13-2007 resulted in about 611,000,000 entries forWindows, 359,000,000 entries for Linux, 248,000,000 entries for OS X, and 142,000,000 entries for

Unix respectively. Without doubt, GNU/Linux is one of the most talked about operating systems onthe Internet.

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Author-created Version: The original publication is accessible fromhttp://ideas.repec.org/a/jae/japmet/v23y2008i2p279-286.html.

In this paper, we review this resource from the perspective of econometricians. In thenext section, we will supply some background information about GNU/Linux and explain

its benefits and disadvantages. In section three, we will discuss hardware requirements,installation, and other methods to start making use of GNU/Linux instantly. This willbe followed by an overview of various open source econometric and statistical softwarepackages hosted by this platform. Section five concludes. For additional information,the reader is referred to MacKinnon (1999), which provides a detailed, albeit slightlyoutdated, review of the Debian GNU/Linux distribution from the point of view of aneconometrician.

2 The GNU/Linux Platform

The roots of GNU/Linux go back to 1985, when the programmer Richard Stallman re-signed from MIT and established the nonprofit Free Software Foundation (FSF) in Boston,MA, USA. Frustrated by the commercialization of computer programs, and believing thatsoftware should be free in accordance with the classical spirit of scientific collaboration,Stallman (1985) had already started working toward a free and Unix compatible operat-ing system called GNU.2 Over the next several years, Stallman and his team developed anumber of tools such as the gcc compiler, the emacs text editor and the bash shell,along with most of the core libraries of a standard Unix system. However, by 1991, theGNU project was still missing a kernel, the essential component of an operating systemresponsible for communication between hardware and software. This piece came from

Linus Torvalds, a second year college student at the University of Helsinki, who usedthe GNU tool set to start writing the Unix compatible Linux kernel as a hobby project.In the years that followed, with the help of an ever increasing number of volunteers whoshared their ideas and contributions over the Internet, GNU/Linux came to be the biggestcollaborative project in human history.

GNU/Linux is free/libre and open source software3 (FLOSS) and is released under theGNU General Public License (GPL) of the FSF.4 The GPL enables users to freely study,modify, and share programs, also ensuring that the modified versions can never becomeproprietary. Today, GNU/Linux is a versatile and powerful operating system which offersa number of ethical, technical, and practical advantages, that we will describe below.

For some, the main motivation for adopting GNU/Linux is a matter of principle.Among the few users who actually bother reading the End-User License Agreement(EULA) of a commercial operating system, many discover that they do not agree with allof its contents. On the other hand, according to most GNU/Linux users, free circulationof ideas, as embodied in a software program, is the key to human progress. Therefore,

2GNU is a recursive acronym, which stands for GNUs Not Unix.3The FSF is based on assigning a high value to freedom in software, however, this principle is not

properly captured by the word free in the English language. Consequently, the French/Spanish wordlibre is often used to distinguish freeware (gratis software) from free (libre) software, which liberatescomputer users from proprietary software under restrictive licensing terms.

4The terms under which software is released are generally referred to as a license. Although the GPL

is the predominant type of license in the FLOSS world, some programs are released under different terms.See de Laat (2005) for a review.

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source code should be made public and has to be protected from becoming proprietary.This idea goes hand in hand with the ongoing trend toward openness in economic analysis.

With GNU/Linux, computer users have access to a completely transparent and restrictionfree computing environment, where every protocol and process is open to inspection andintervention. Plus, it is freely available to all, greatly facilitating peer review and researchreplication. As a result, choosing GNU/Linux is considered a step in the right directionby many users, who feel that it is their responsibility to support the use and developmentof free/libre software tools for conducting research in economics.

Among the practical reasons for choosing GNU/Linux is the outstanding stability ofthis platform, which is a particularly important consideration for econometricians whoregularly run extensive computational tasks that take days and even weeks to complete.A properly configured GNU/Linux system will run without interruption for as long as thehardware keeps working. In addition, with full multi-tasking support, multiple devicescan be accessed simultaneously, and numerous programs can be run in the background.Due to these features, 376 of the worlds top 500 supercomputers are now running on theGNU/Linux platform.5

Another reason is that GNU/Linux offers excellent security. This is partly due to itsarchitecture, which makes it almost impossible for harmful programs to cause system-wide damage. Moreover, it is very difficult for a virus to hide itself in open code.Also, virus writers normally choose more popular operating systems as their target.Peeling and Satchell (2001) report that the Windows operating system is threatened byabout 60,000 known viruses. These programs cannot cause damage on GNU/Linux, whichis known to have around 40 native viruses, most of which were designed as a research cu-

riosity.6 The majority of GNU/Linux users do not even bother installing virus protectionsoftware on their computers.

In addition, GNU/Linux offers the flexibility of being used either via a graphicalcommand interface (which is what Windows and Macintosh users are accustomed to) orvia the shell. The shell, or command line interface, is the traditional way of interactingwith the system on UNIX machines. Despite its arcane-looking appearance, the shellmakes it easy to combine several programs to perform complex operations such as datamining. For example, the command

find / -name "*.csv" -exec grep -l 12345 {} \; | sort

will combine find, grep, and sort commands to search inside all .csv files in the com-puter and list in alphabetical order the ones that contain the string 12345. Moreover,the shell interface allows the user to run commands on remote machines very easily via anordinary Internet connection, which is extremely useful for computationally demandingtasks.

Finally, another reason why many are adopting GNU/Linux as their main computingplatform is the quality of software. Written without commercial concerns, most GNU

5Reported by Top500 Supercomputer Sites (http://www.top500.org/stats) accessed on 4-13-2007.

6One such example is the Bliss virus, which was created as a proof-of-concept. Bliss keeps a log of all

its actions in the /tmp/.bliss file and even provides the thoughtful --bliss-uninfect-files-pleasecommand line option. It never became widespread.

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programs can be considered a labor of love. For example, even the simple calculatorprogram Calc is capable of doing arbitrary precision arithmetic, symbolic algebra, and

graphics, as well as operations on matrices, complex numbers, calendar dates, and so on.Notwithstanding its important advantages, GNU/Linux also has some drawbacks.One of the shortcomings frequently cited in the past was the lack of commercial softwaresupport. While this is much less an issue nowadays, prospective users should check theavailability of any software that they find indispensable for doing research. Anotherdisadvantage that GNU/Linux users commonly encounter is the fact that some exotichardware may not work properly, if at all. This is a side-effect of the dominance of theMS Windows platform: Hardware vendors do not always release Linux drivers and areoften reluctant to provide detailed specifications of their hardware. In this case, devicedrivers have to be reverse-engineered. Consequently, some pieces of hardware can bemanaged by the Linux kernel only weeks, if not months, after their introduction. Whilethe list of devices that is supported by the Linux kernel is already enormous and in rapidexpansion, it is always best to check beforehand. A comprehensive list of supportedhardware can be found at http://en.tldp.org/HOWTO/Hardware-HOWTO/index.html.

In addition, migrating to a new and unfamiliar operating system can be discouraging.Therefore, it is important to accept from the beginning that it will take some time andeffort to adapt to a new environment. However, the very nature of FLOSS makes usersvery willing to cooperate with each other. Almost any question one may wish to ask hasalready been answered on some web page. Search engines are the FLOSS equivalent ofcustomer support for proprietary software.

GNU/Linux is designed for computer literate people. Having more control over the

computer means doing some manual configuration or using the console to enter commandsevery so often. Consequently, as the saying goes: If your VCR is blinking 12:00, youdont want Linux.

3 Obtaining and Installing GNU/Linux

Unlike other operating systems, GNU/Linux does not refer to a single product. In orderto better satisfy different needs and preferences, it comes in various flavors called distri-butions. While there are hundreds of distributions,7 most of these are modified versionsof the several well-established ones tailored for a certain language or a specific type ofusage. A typical distribution includes the Linux kernel, the GNU tools and libraries, theX graphical system, a desktop environment such as KDE or Gnome, along with hundredsof freedom respecting programs for handling different tasks.

Distributions can be either commercial or noncommercial. A commercial distributionsuch as Mandriva or Red Hat Enterprise Linux usually comes with a printed manual andtelephone or email support for a certain number of weeks or months. On the other hand,noncommercial distributions usually offer detailed documentation in electronic formatand community support through Internet forums. Some of the leading non-commercial

7DistroWatch (http://www.distrowatch.com) is a popular destination for obtaining news and in-formation regarding the many flavors of GNU/Linux.

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distributions include Debian, Ubuntu, Fedora, openSUSE, Gentoo, and Slackware. Thisreview focuses on Debian GNU/Linux, which is a truly global and hardware agnostic

distribution. Also, Debian supports a very large library of software packages, includingthose particularly useful for econometricians.Most noncommercial distributions including Debian are obtainable from the Internet

in the form of downloadable .iso files. These large files contain exact images of a CDor a DVD for online distribution, and need to be written on blank media once acquired.As an alternative, the Debian web site (http://www.debian.org ) also provides a list ofonline vendors, which sell various distributions for a little more than the cost of mediaand shipping charges.

GNU/Linux is capable of running on a large variety of hardware architectures includ-ing Intel x86 based processors, Intel IA-64, AMD64, IBM/Motorola PowerPC, SPARC,DEC Alpha, and ARM, with an extremely efficient use of hardware. Accordingly, anyPC with a Pentium II or above and at least 128 MB ram is capable of running mostGNU/Linux distributions. The graphical desktop environment tends to use a large partof system resources. Consequently, the requirements will be significantly less if the ma-chine is used for less intensive tasks such as running a dedicated web server, a firewall ora database back-end. Recent versions of the Linux kernel support up to 64GB of RAMand file systems as large as 16 terabytes (1 terabyte = 1024GB).

Installing GNU/Linux is as simple and as fast as other operating systems. Mosthardware is supported out of the box and automatically detected during installation.The user is also given the option of keeping the existing setup on the computer, makingit possible to have more than one operating system on a single PC. Once the installation

is complete, maintaining the system and adding or removing software is easily done usingpackage managers. These smart programs use various online software repositories tofetch and configure the latest updates and additional software packages automatically.The Debian distribution has a tradition of being extremely good at this. Nearly allend-user programs (including upgrades) can be fetched from the official Debian archivesthrough simple commands, keeping the system clean, consistent, and well-organized at alltimes. When a new version of a program is released by its authors, a Debian maintainerrepackages it and puts it into the unstable repository; after 10 days, if no critical bugs arediscovered, it migrates into the testing repository. At regular intervals, the testing archiveis frozen and all bugs are eliminated. This becomes the stable distribution. Debian users

can choose to use either repository; most desktop users choose the testing repository.The stable repository, which contains somewhat outdated versions of the programs, isnormally chosen for servers that need virtually bug-free software. At the time of writing,the number of packages in the official Debian testing repository was over 19,000.

GNU/Linux can be used even without installing on a hard drive. There are variousself-configuring live distributions which are capable of running entirely from removablemedia such as a CD or a memory card. These live distributions instantly turn anycomputer into a full-blown GNU/Linux workstation and offer an effortless way to testdrive this platform. They also make excellent rescue disks that can be used to retrievefiles in case the computer fails to start. Some of the Debian based live distributions

include Knoppix, Ubuntu, Mepis, and Quantian. These distributions also offer hard drive

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installation option and are recommended for new users. Quantian is a remastering of thehighly regarded Knoppix distribution, tailored to include a large number of quantitative,

numerical, and scientific software of interest to econometricians. Being a live DVD,however, it cannot be used on older computers. See Eddelbuettel (2000) for a review ofthis Debian based distribution.

4 Freedom Respecting Software for Economists

One of the main considerations for choosing an operating system is the amount andquality of software supported by the platform. While today most commercial scientificprograms are available for GNU/Linux, there is also a large selection of high qualityFLOSS alternatives. In fact, the math and science sections of Debian repositories feature

hundreds of Free Software packages. In this section, we will attempt to provide a basicoverview of some of the popular freedom respecting programs for doing research in eco-nomics. The functionality offered gratis by these programs to individual users, as well aseconomics departments, would require substantial financial resources to acquire throughproprietary software. Also, being FLOSS, most of these programs are already ported tocommercial platforms. This makes it possible for prospective users to become familiarwith the software before actually switching to GNU/Linux.

The leading econometrics package developed for GNU/Linux is GRETL, GNU Re-gression, Econometrics and Time Series Library (http://gretl.sourceforge.net ).This sophisticated program features an intuitive graphical user interface, an integrated

scripting language, and a wide variety of econometric tests and estimators. It is alsoknown to have high numerical accuracy and is capable of producing publication qual-ity output by integrating with gnuplot (http://www.gnuplot.info ), a portable dataand function plotting utility. See Mixon and Smith (2006) and Yalta and Yalta (2007)for additional information regarding GRETL and Racine (2006) for a recent review ofgnuplot.

In addition to GRETL, GNU-R (http://www.r-project.org) provides a powerfulprogramming language and a statistical environment similar to the S language. R is veryextensible, with over 1000 add-on packages obtainable from CRAN, The ComprehensiveR Archive Network. It is also highly regarded for the quality of its graphical output. Twoseparate reviews of this program from the perspective of econometricians are provided byCribari-Neto and Zarkos (1999) and Racine and Hyndman (2002). Also, for time-seriesanalysis, an interesting cross-breed case is JMulTi; see Lutkepohl and Kratzig (2004)and the project website http://www.jmulti.com . Despite having Gauss, a proprietaryproduct, as its main computational engine, JMulTi itself is released under a GNU license.It is an excellent time-series analysis package, especially for multiple time series methods(VARMAs and cointegrated systems).

GNU/Linux also offers several good quality FLOSS alternatives for numerical com-putation. GNU Octave (http://www.gnu.org/software/octave) is a high-level, matrixbased language mostly compatible with the commercial Matlab program. Alternatively,Scilab (http://www.scilab.org ) is also a numerical computational package featuring a

large variety of built-in mathematical functions and rich data structures. However, while

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Scilab is a gratis and open source program, certain restrictions in its license disqualify itas Free Software. For further information on GNU Octave and Scilab, see Eddelbuettel

(2000) and Mrkaic (2001), respectively.Econometric analysis frequently requires manipulation of symbolic expressions. WhileGNU Octave and Scilab provide some of this functionality, dedicated alternatives are alsoavailable. Maxima (http://maxima.sourceforge.net) is a full-featured computer alge-bra system capable of symbolic differentiation and integration, handling Taylor series,Laplace transforms, ordinary differential equations and systems of linear equations. It of-fers arbitrary precision arithmetic and supports number sizes limited by machine memory.There is also an impressive utility named Qalculate! (http://qalculate.sourceforge.net ).Despite being designed as a desktop calculator, Qalculate! offers symbolic calculation,arbitrary precision, and supports constants, vectors, matrices, and complex numbers.

For creating technical documents, most GNU/Linux distributions support the teTE

Xpackage (http://www.tug.org/tetex ), which provides a TEX and LATEX installationthat consists only of free/libre software, although most distributions are now phasing outteTEX in favor of the more modern alternative TEXlive (http://www.tug.org/texlive ).A variety of editors are also available such as LYX(http://www.lyx.org ), emacs/AUCTEX(http://www.gnu.org/software/auctex), Kile (http://kile.sourceforge.net ), andTexmaker (http://www.xm1math.net/texmaker) to name a few. See Koning (2001) foran overview of different LATEX editors and installations.

Almost all GNU/Linux distributions come with a preinstalled copy of OpenOffice.org(http://www.openoffice.org ), a multilingual and open source office suite that providesall the features expected from a collection of productivity programs. OpenOffice.org is

capable of reading and writing Microsoft Office documents and has the additional featureof saving documents as .pdf files as well as in LATEX format. There is also an excellentspreadsheet program named Gnumeric (http://www.gnome.org/projects/gnumeric),which offers better numerical accuracy than the leading commercial alternative, as dis-cussed by McCullough (2005).

Two programs worth mentioning are openMosix (http://openmosix.sourceforge.net )and Xen (http://www.cl.cam.ac.uk/Research/SRG/netos/xen). openMosix is a clus-ter management system for parallel computing. It is used to turn a network of ordinarycomputers into a supercomputer, which can be put to work for computationally intensiveprojects such as simulations and bootstraps.8 Xen, on the other hand, is a virtual ma-

chine monitor. Using Xen, it is possible for the user to create a virtual computer runninganother operating system inside a window in GNU/Linux.

Finally, as wide as the spectrum of available free software is, the possibility thatan economist might need to run proprietary software on a GNU/Linux system is worthconsidering. A few econometric packages are not available under GNU/Linux as yet,but the majority of the most widely used ones are. GNU/Linux versions exist of Gauss,Mathematica, Matlab, RATS, Stata, and TSP, to name but a few.9 The same goes for

8For further information on parallel computing clusters, see Creel (2007), which shows how to reducethe computation of a Monte Carlo Study that involves 4,000,000 nonlinear optimizations to several hoursusing the ParallelKnoppix GNU/Linux distribution.

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In fact, Matlab and Stata for GNU/Linux seem to handle large datasets better then their Windowscounterparts.

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popular compilers and numerical libraries, such as the Intel FORTRAN compiler andthe NAG and IMSL libraries. In addition, the Wine project (http://www.winehq.org )

should be mentioned: Its aim is to create a software compatibility layer which will enableusers to run unmodified Windows software with little or no performance penalty. Thecurrent version, which is still considered beta, can already handle several Windowsprograms satisfactorily. For example, some versions of Eviews can easily be installed ona GNU/Linux machine using Wine.

5 Conclusion

The GNU/Linux platform provides a versatile, stable, and secure computing environmentideal for conducting econometric research. It also hosts a large collection of free/libre and

open source programs that surpass their commercial alternatives in terms of both featuresand quality. Moreover, GNU/Linux offers significant advantages such as freedom and zerocost availability, which make it an excellent operating system in an academic setting.

Changing operating systems is not as difficult as it sounds, especially when the tran-sition is done gradually. The various live CD/DVD distributions provide an effortlessway to become familiar with the new platform. Afterwards, a dual installation can beconsidered, where the new user can easily switch back to the previous system for per-forming certain tasks he or she is not yet comfortable carrying out under GNU/Linux. Acomplete migration takes time. However, the stimulation of learning new things and thefinal feeling of liberation will make the effort worthwhile.

Acknowledgements

We wish to thank James MacKinnon for his suggestions and corrections on earlier drafts.For his comments, we also wish to thank Richard Stallman, who does not endorse theuse of any non-free software mentioned in this paper.

References

Creel M. 2007. I ran four million probits last night: HPC clustering with ParallelKnoppix.Journal of Applied Econometrics, 22: 215223.

Cribari-Neto F, Zarkos SG. 1999. R: Yet another econometric programming environment.Journal of Applied Econometrics, 14: 319329.

de Laat P. 2005. Copyright or copyleft? An analysis of property regimes for softwaredevelopment. Research Policy, 34: 15111532.

Eddelbuettel D. 2000. Econometrics with Octave. Journal of Applied Econometrics, 15:531542.

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http://ideas.repec.org/a/jae/japmet/v23y2008i2p279-286.htmlhttp://www.winehq.org/http://www.winehq.org/http://ideas.repec.org/a/jae/japmet/v23y2008i2p279-286.html


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Koning RH. 2001. A comparison of different LATEX programs. Journal of Applied Econo-metrics, 16: 8192.

Lutkepohl H, Kratzig M (eds.). 2004. Applied Time Series Econometric. Cambridge Uni-versity Press, Cambridge.

MacKinnon JG. 1999. The Linux operating system: Debian GNU/Linux. Journal ofApplied Econometrics, 14: 443452.

McCullough BD. 2005. Fixing statistical errors in spreadsheet software: the cases of Gnu-meric and Excel. URL http://www.csdassn.org/software_reports/gnumeric.pdf,[Online; retrieved September 14, 2006].

Mixon JW, Smith RJ. 2006. Teaching undergraduate econometrics with GRETL. Journal

of Applied Econometrics, 21: 11031107.

Mrkaic M. 2001. Scilab as an econometric programming system. Journal of Applied Econo-metrics, 16: 553559.

Peeling N, Satchell J. 2001. Analysis of the Impact of Open Source Software. URLhttp://www.govtalk.gov.uk/documents/QinetiQ_OSS_rep.pdf, [Online; retrievedSeptember 14, 2006].

Racine J. 2006. gnuplot 4.0: a portable interactive plotting utility. Journal of AppliedEconometrics, 21: 133141.

Racine J, Hyndman R. 2002. Using R to teach econometrics. Journal of Applied Econo-metrics, 17: 175189.

Stallman R. 1985. The GNU manifesto. Dr. Dobbs Journal of Software Tools, 10: 3035.

Yalta AT, Yalta AY. 2007. GRETL 1.6.0 and its numerical accuracy. Journal of AppliedEconometrics, 22: 849854.

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