Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers! David A. Wheeler http://www.dwheeler.com/contactme.html Revised as of November 7, 2004 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’s goal is to show that you should consider using OSS/FS when acquiring software. This paper examines market share, reliability, performance, scalability, security, and total cost of ownership. It also has sections on non- quantitative issues, unnecessary fears, OSS/FS on the desktop, usage reports, governments and OSS/FS, other sites providing related information, and ends with some conclusions. An appendix gives more background information about OSS/FS. You can view this paper at http://www.dwheeler.com/oss_fs_why.html (HTML format). Palm PDA users may wish to use Plucker to view this. A short briefing based on this paper is also available in PDF and Open Office Impress formats (for the latter, use Open Office Impress). Old archived copies and a list of changes are also available. 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 study and modify the program, and to redistribute copies of either the original or modified program (without having to pay royalties to previous developers). This goal of this paper is to show that you should consider using OSS/FS when you’re looking for software, based on quantitative measures. 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 many 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 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. Certainly, there are many who believe this is true from ethical, moral, or social grounds, users do have control and flexibility advantages when they can modify and maintain their own software, and some countries perceive political advantages to not depending on a company from another country. However, no numbers could prove the broad claim that OSS/FS is always better. 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, some OSS/FS software is at least as good or better than its proprietary competition. Of course, some OSS/FS software is technically poor, just as some proprietary software is technically poor, and even very good software may not fit your specific needs. But although most people understand the need to compare proprietary products before using them, many people fail to even consider OSS/FS products. This paper is intended to explain why acquirers should consider OSS/FS alternatives. This paper doesn’t examine transition approaches, but it’s worth noting that organizations can transition to OSS/FS in part or in stages, which for many is a more practical transition approach. I’ll emphasize the operating system (OS) known as GNU/Linux (which many 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; today’s Unix systems include many OSS/FS components or software primarily derived from OSS/FS components. Thus, comparing proprietary Unix systems to OSS/FS systems (when examined as whole systems) is often not as clear-cut. This paper uses 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 OS (MacOS OS X) presents the same kind of complications; older versions of MacOS were wholly proprietary, but Apple’s OS has been redesigned so that it’s now based on a Unix system with substantial contributions from OSS/FS programs. Indeed, Apple is now openly encouraging collaboration with OSS/FS developers. Sometimes it’s illegal to publicly criticize proprietary software, which does reduce the amount of information available. Many proprietary product licenses include clauses that forbid public criticism of the product without the vendor’s permission. Obviously, there’s no reason that such permission would be granted if a review is negative! As a result, reviewers may change their report so it can be published, or not report at all (they might not even start the evaluation). Some laws, such as UCITA (a law in Maryland and Virginia), specifically enforce these clauses forbidding free speech, and in many other locations the law is unclear - making researchers bear the risk that these clauses might be enforced. These legal risks do cause a chilling effect on researchers, and it’s not a theoretical problem; these license clauses have already prevented some public critique. In spite of these legal tactics to prevent disclosure of data not controlled by a vendor, there is still a great deal of publicly available data, as this paper shows. This paper omits or at least tries to warn about studies funded by a product’s vendor. Remember that vendor-sponsored studies are often rigged (no matter who the vendor is) to make the vendor look good instead of being fair comparisons. Todd Bishop’s January 27, 2004 article in the Seattle Post-Intelligencer Reporter discusses the serious problems when a vendor funds published research about itself. A study funder could directly pay someone and ask them to lie, but it’s not necessary; a smart study funder can produce the results they wish without, strictly speaking, lying. For example, a study funder can make sure that the evaluation carefully defines a specific environment or extremely narrow question that shows a positive trait of their product (ignoring other, probably more important factors), require an odd measurement process that happens show off their product, seek unqualified or unscrupulous reviewers who will create positive results (without careful controls or even without doing the work!), create an unfairly different environment between the compared products (and not say so or obfuscate the point), require the reporter to omit any especially negative results, or even fund a large number of different studies and only allow the positive reports to appear in public. That doesn’t mean that all vendor-funded studies are misleading, but many are, and there’s no way to be sure which studies are actually valid. For example, Microsoft’s “get the facts” campaign identifies many studies, but they’re almost entirely vendor-funded! And Microsoft is by no means the only company that does this; many companies do this, and the concerns about vendor-funded studies applies equally to vendors of OSS/FS products. After a pair of vendor-funded studies were publicly lambasted, Forrester Research announced that it will no longer accept projects that involve paid-for, publicized product comparisons. One ad, based on a vendor-sponsored study, was found to be misleading by the UK Advertising Standards Authority (an independent, self-regulatory body), who formally adjudicated against the vendor. This example is important because the study was touted as being fair by an “independent” group, yet it was found unfair by an organization who examines advertisements; failing to meeting the standard for truth for an advertisement is a very low bar. I’m independent; I have received no funding of any kind to write this paper, and I have no financial reason to prefer OSS/FS or proprietary software. This paper includes data over a series of years, not just the past year; all relevant data should be considered when making a decision, instead of arbitrarily ignoring older data. Note that the older data shows that OSS/FS has a history of many positive traits, as opposed to being a temporary phenomenon. You can get a more detailed explanation of the terms “open source software” and “Free Software”, as well as related information, from the appendix and 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. Software for which the source code that can be viewed, but cannot modified and redistributed without further limitation (e.g., “source viewable” or “open box” software, including “shared source” and “community” licenses), are not considered here since they don’t meet the definition of OSS/FS. Many OSS/FS programs are commercial programs, so don’t make the mistake of thinking OSS/FS is equivalent to “non-commercial” software (indeed, any article making this mistake should be ignored since it is obviously poorly researched).