Linux also attacked Microsoft and Unix where they had weaknesses. Microsoft, which declined to comment for this report, is dominant in desktops. But competition is stronger in servers, where Linux is most widely used. And Linux was cheap, while Unix customers had to pay a premium.
Linux programmers didn't have to start from scratch to build this success. Linux plugged into the GNU's Not Unix (GNU) effort to clone Unix, adopting many of the design and utilities of Unix if not its exact software code. But the programmers did have to struggle for years without support from those who designed chips, network cards, and just about every other computer component that requires a software "driver" to work with an operating system.
"Early on, Linux developers wrote drivers without help from the hardware manufacturers," said Bryan Sparks, founder of Caldera and now chief executive of embedded Linux company Lineo. "Now that's flipped. Now the hardware peripheral manufacturers are writing drivers that support Linux themselves."
Sparks also praised Torvalds as a practical leader who didn't suffer from the arrogance of some others. "He was in the right place at the right time with the right personality," and thus the group that became Caldera decided to use Linux, not NetBSD or other alternatives.
Challenges remain
But other operating systems have risen and fallen, and Linux isn't guaranteed success. Many of the companies backing Linux have suffered or expired altogether in today's unforgiving financial environment, failing to convert Linux's popularity into corporate profits.
"It's easier to write a clone of Unix than to be in the lead and say, 'Where do we go from here?'" Sparks said.
IBM's Frye said Linux's biggest challenge is to increase the number of business software companies supporting the operating system.
And Microsoft, once trying to dig into the Unix server market at a more leisurely pace, now has a full-court press on Linux and the General Public License (GPL) that underlies it.
"Microsoft and others are moving quickly," Sparks said. "The fact is, (Microsoft has) US$30 billion to spend and a whole bunch of engineers to put on the problem."
Still, Microsoft must worry, particularly because Linux is such a popular learning tool in schools.
"The trend is not good" for Microsoft, Enderle said. "More and more kids are coming out of school with a Linux bent. People doing open source are often at the top of their class--similar to the people who drove Windows into the market a decade ago."
My employer is not happy with XP
and we are evaluating the cost of migration to Linux.
Why anyone would use XP is beyond me.