(OSS/FS)? Look at the Numbers!
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Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers! David A. Wheeler [email protected] Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers! Table of Contents Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers!..........................................1 Introduction.........................................................................................................................................................2 Market Share.......................................................................................................................................................4 Reliability...........................................................................................................................................................11 Performance......................................................................................................................................................15 Scaleability.........................................................................................................................................................21 Security..............................................................................................................................................................22 Total Cost of Ownership (TCO)......................................................................................................................31 Non−Quantitative Issues..................................................................................................................................36 Unnecessary Fears............................................................................................................................................39 Other Information............................................................................................................................................45 Conclusions........................................................................................................................................................48 i Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers! David A. Wheeler [email protected] Revised as of May 1, 2002 This paper provides quantitative data that, in many cases, using open source software / free software is a reasonable or even superior approach to using their proprietary competition according to various measures. This paper examines market share, reliability, performance, scaleability, security, and total cost of ownership. It also has sections on non−quantitative issues, unnecessary fears, and other sites providing related information, and ends with some conclusions. Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers! 1 Introduction Open Source Software / Free Software (OSS/FS) has risen to great prominence. Briefly, OSS/FS programs are programs whose licenses give users the freedom to run the program for any purpose, to modify the program, and to freely redistribute either the original or modified program (e.g., without further limitations or royalty payments). Some sites provide a few anecdotes on why you should use OSS/FS, but for many that's not enough information to justify using OSS/FS. Instead, this paper emphasizes quantitative measures (such as experiments and market studies) on why using OSS/FS products is, in a number of circumstances, a reasonable or even superior approach. I should note that while I find much to like about OSS/FS, I'm not a rabid advocate; I use both proprietary and OSS/FS products myself. Vendors of proprietary products often work hard to find numbers to support their claims; this page provides a useful antidote of hard figures to aid in comparing these proprietary products to OSS/FS. Note that this paper's goal is not to show that all OSS/FS is better than all proprietary software. There are those who believe this is true from ethical, moral, or social grounds, but no numbers could prove such a broad statement. Instead, I'll simply compare commonly−used OSS/FS software with commonly−used proprietary software, to show that at least in certain situations and by certain measures, OSS/FS is at least as good or better than its proprietary competition. I'll emphasize the GNU/Linux operating system (which some abbreviate as ``Linux'') and the Apache web server, since these are some of the most visible OSS/FS projects. I'll also primarily compare OSS/FS software to Microsoft's products (such as Windows and IIS), since Windows has a significant market share and Microsoft is one of proprietary software's strongest proponents. I'll mention Unix systems in passing as well, though the situation with Unix is more complex; many Unix systems include a number of OSS/FS components or software primarily derived from OSS/FS components. Thus, comparing proprietary Unix systems to OSS/FS systems (when examined as entire systems) is often not as clear−cut. I use the term ``Unix−like'' to mean systems intentionally similar to Unix; both Unix and GNU/Linux are ``Unix−like'' systems. The most recent Apple Macintosh operating system (MacOS OS X) presents the same kind of complications; older versions of MacOS were entirely proprietary, but Apple's operating system has been redesigned so that it's now based on a Unix system with a substantial contribution from OSS/FS programs. Indeed, Apple is now openly encouraging collaboration with OSS/FS developers. I include data over a series of years, not just the past year; I believe that all relevant data should be considered when making a decision, instead of arbitrarily ignoring older data, and the older data shows that OSS/FS has a history of many positive traits. You can get a more detailed explanation of the terms ``open source software'' and ``Free Software'', as well as related information, from my list of Open Source Software / Free Software (OSS/FS) references at http://www.dwheeler.com/oss_fs_refs.html. Note that those who use the term ``open source software'' tend to emphasize technical advantages of such software (such as better reliability and security), while those who use the term ``Free Software'' tend to emphasize freedom from control by another and/or ethical issues. The opposite of OSS/FS is ``closed'' or ``proprietary'' software. Note that many OSS/FS programs are commercial programs, so don't make the mistake of calling OSS/FS software ``non−commercial.'' Almost no OSS/FS programs are in the ``public domain'' (which has a specific legal meaning), so avoid that term as well. Some call OSS/FS software ``public service software'', since often these software projects are designed to serve the public at large, or ``libre software'' (where libre means free as in freedom). Below is data discussing market share, reliability, performance, scaleability, security, and total cost of ownership. I close with a brief discussion of non−quantitative issues, unnecessary fears, other sites providing Introduction 2 Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers! related information, and conclusions. Introduction 3 Market Share Many people believe that a product is only a winner if it has significant market share. This is lemming−like, but there's some rationale for this: products with big market shares get applications, trained users, and momentum that reduces future risk. Some writers argue against OSS/FS or GNU/Linux as ``not being mainstream'', but if their use is widespread then such statements reflect the past, not the present. There's excellent evidence that OSS/FS has significant market share in numerous markets: 1. The most popular web server has always been OSS/FS since such data have been collected, for example, Apache is currently the #1 web server. Netcraft's statistics on webservers have consistently shown Apache (an OSS/FS web server) dominating the public Internet web server market ever since Apache became the #1 web server in April 1996. Before that time, the NCSA web server (Apache's ancestor) dominated the web from August 1995 through March 1996 − and it is also OSS/FS. For example, in April 2002, Netcraft polled all the web sites they could find (totaling 37,585,233 sites), and found that of all the sites they could find, Apache had 56.38% of the market, Microsoft had 31.96% of the market, Zeus had 2.26%, and iPlanet (aka Netscape) had 2.21%. More recently, Netcraft has been trying to separately count only ``active'' sites. The problem is that many web sites have been created that are simply ``placeholder'' sites (i.e., their domain names have been reserved but they are not being used); such sites are termed ``inactive.'' Netcraft's count of only the active sites is probably a far more relevant figure, since this shows the web server selected by those who choose to develop a web site. When counting only active sites, Apache does even better; in April 2002, Apache had 64.38% of the web server market, Microsoft had 27.15%, iPlanet had 1.71%, and Zeus had 1.12%. Market Share for Active Web Servers, June 2000 − April 2002 The same overall result has been determined independently by E−soft − their report published April 1, 2002 surveyed 5,940,265 web servers in March 2002 and found that Apache was #1 (65.80%), with Microsoft IIS being #2 (25.30%). Obviously these figures fluctuate monthly; see Netcraft and E−soft for the latest survey figures. 2. GNU/Linux is the #2 web serving operating system on the public Internet (counting by physical machine), according to a study by Netcraft surveying March and June 2001.