Yet it has become clear that Linux is not "free," even though the source code is. It still takes maintenance and system administrators (who can be hard to find and may command higher salaries) familiar with the operating system (OS) to manage it.
It's also a safe bet that as Linux becomes more popular, it will become the target of more hacks and therefore more vulnerable. According to an April 2004 Yankee Group report by Laura Didio, "[i]t is clear from recent alerts that the number of Linux hacks is rising steadily and will continue to do so."
So, if the most oft-cited reasons for switching to Linux from UNIX or Windows are, basically, moot (depending on your specific set of circumstances and who you talk to, of course), what then is left to consider?
Well, at least according to some, flexibility is the key issue as opposed to TCO, ROI, security or reliability -- although those arguments still hold sway with others.
"Without the source code being available, the customer has no choice other than perhaps go to another vendor," said Jon Hall, the executive director of Linux International, a non-profit Linux promotional organization. "So the question you have to ask yourself is, 'How much does it cost your company not to be able to do those things that the vendor won't do?'"
This is why, according to Hall, the city of Munich in Germany recently adopted Linux as its platform of choice over Microsoft, even though Microsoft was cheaper. The city, said Hall, was more interested in the ability to modify the OS at will than saving money on the initial purchase.
Also, while Hall was with Compaq's (now Hewlett-Packard) Digital UNIX marketing group, for example, customers put in requests for more than 650 changes to its UNIX offering. Only 50 were ever implemented by the engineers, leaving 600 requests to languish unheeded.
Without the ability to access source code and modify it to meet your particular needs, the argument goes, then you are beholden to the vendor for all OS modifications unless you can afford a source-code license.
With the source-code access Linux provides, however, you are able make those changes at will and for free provided you publish those changes, updates, fixes, etc. to the open source community at large.
"There's just an almost unbelievable amount of innovation going on around the platform," said Joshua Harr, CTO of Linux Networx, a cluster computing vendor, "very creative things that obviously are totally impossible with Windows. As those projects gain merit, the distribution vendors ... adopt those into their Linux distributions and they become standard features."
That is why Linux Networx standardized on Linux for its cluster offerings and why its customers are also considering Linux for many applications, he said. This is also why Linux code is of such high quality. More eyes on the code mean more scrutiny which in turn produces a better product overall.
Wall Street banks, for example, have embraced Linux because of the ability it gives them to innovate, said Harr.
Adrian Jones, senior vice president at BakBone, a provider of disaster recovery software for Linux, UNIX and Windows installations, however, counters the flexibility argument somewhat.
While agreeing with the flexibility argument in principal the reason his customers cite for switching to Linux is reliability, he said. Flexibility comes in third or fourth on his list of reasons to switch. Jones bases his observation on the fact that fully 40% of the company's back-up business is coming from enterprise Linux installs today, he said.
"Linux has had good reputation from a quality and reliability perspective and that's where other older technology like UNIX and Solaris have not," said Jones. "That's where CIOs have become more comfortable with it, they can guarantee their data, they can guarantee what there using with Linux. And that's why people are moving."