Linux Distributors

While people can obtain basic copies of Linux free of cost, distributors including Red Hat and Novell charge annual subscription fees, ranging from $35 for a desktop version of Linux to $1,500 for a high-end server. The reason such customers are willing to pay? Those packages come with instructions, free updates, and customer service.

Computer Makers

Companies such as Dell, Hewlett- Packard, and IBM sell PCs and servers preloaded with Linux. They capitalize on the ability to sell machines without an up-front charge for the operating system, which can total thousands of dollars. For HP, Linux sales accounted for 18% of its $15.4 billion in server revenues last fiscal year, up from 10% three years ago.

Software Companies

A swarm of software companies sell products that run on top of Linux. About 10% of giant SAP's corporate-application sales are derived from Linux-related products. In addition, upstart mySQL makes a database that runs on Linux and already has reached 6 million installations, including at powerhouses such as NASA and Net-search giant Google.

Technology Linux

How To Profit From Free Software

IBM, Red Hat, and other tech companies pay the salaries of programmers to help improve the Linux operating system. Here's what they get out of it: