The best-known open-source project is Linux, a Unix-like operating system, begun by Linus Torvalds and now embraced by most of the world's top computing companies.
Businesses have a handful of reasons to look to open-source software. It's free to try out and can be lower-cost to use, although products often aren't as full-featured. And open-source software presents an alternative to customers that fear buying proprietary software will lock them into a relationship with the company that sold it.
The open-source movement is an offshoot of the work of Richard Stallman, whose Gnu's Not Unix (GNU) project to clone Unix introduced the General Public License (GPL) that provides a legal framework governing many open-source projects. GNU also provided many important tools that the best-known open-source project, Linux, used and built upon.
Boosted by companies such as Red Hat and SuSE Linux, Linux began spreading across the computing world in the late 1990s, putting pressure both on Microsoft and on Unix vendors. IBM in particular put its considerable muscle behind Linux, bringing it even to its vaunted mainframe server line; market researcher IDC says $2 billion worth of Linux servers were sold in 2002.
While Linux is popular on servers--powerful networked computers that handle round-the-clock data processing and storage tasks--it's not widely used on desktop machines. It's considered too technically difficult by most observers, although Linux backers have begun pushing it for corporate desktop computers used only for a limited range of tasks.
One Linux software company, originally named Caldera and now called SCO Group, failed to make a business of Linux. It acquired much of the Unix intellectual property in 2001 in an attempt to expand its business, but when that didn't work out either, it began a new strategy to profit from that Unix intellectual property. After hiring high-profile attorney David Boies, SCO began arguing that Unix source code and extensions are illegally used in Linux. Its opening salvo in March was ambitious: a lawsuit against IBM alleging that Big Blue violated its Unix contracts with SCO when it moved its own Unix extensions to Linux. Now SCO has begun asking all Linux users to pay it hundreds of dollars each.
SCO's actions haven't been received warmly. IBM countersued SCO in August, bringing four patent infringement claims as well as a vigorous defense of the GPL, and Red Hat sued SCO the same week in an attempt to lay the matter to rest as quickly as possible. Linux advocates have scoffed at SCO's charges, industry analysts have questioned the merits of their arguments, and intellectual property attorneys have advised companies to wait for legal ruling before agreeing to SCO's demands.
Meanwhile, the open-source world moves on. While volunteers and hobbyists are widespread, more mature projects such as Linux often are run by programmers paid for their work. Among other important open-source projects are Apache, which is used to host Web sites; OpenOffice, a competitor to Microsoft Office; MySQL, a database program; Sendmail, server software for delivering e-mail; , a Unix derivative used in Apple's Mac OS X.