Linux is expected to be used on about 17 million Linux PCs in that year, some new and some redeployed with the open-source operating system, bringing the total installed base to 42.6 million, according to the IDC study. And though Linux on PCs still likely will be dwarfed by Windows, IDC forecasts a bigger beachhead: Market share of new and used PCs running Linux is expected to grow from 3 percent in 2003 to 7 percent in 2008.
Much of the industry outside Microsoft is a fan of Linux on desktop and laptop computers. Among companies with Linux PC efforts are, , , , , and .
"For competitors and companies still on the sidelines, this forecast should provide additional justification to the market. Linux is no longer a fringe player. Linux is now mainstream," IDC said in a statement.
The forecasts are from an IDC study of the overall Linux ecosystem, including sales of Linux PCs, servers and packaged software running on those computers. IDC collected the data, but Open Source Development Labs (OSDL), a Linux consortium funded by major computing companies, funded IDC to integrate the data into a single study, IDC analyst Al Gillen said.
OSDL also publicized the story Wednesday, providing some counterweight to Microsoft's "" campaign, which has and to promote Windows at the expense of its rival Linux.
The IDC study estimates the overall Linux ecosystem will grow 25.9 percent annually to reach $35.7 billion in 2008. Of that, IDC estimates $14 billion will be packaged software, $10 billion PCs and $11 billion servers.
For Linux PCs, market share will likely be lower than average in North and South America and higher in two other regions: Europe, the Middle East and Africa on the one hand and Asia-Pacific countries on the other, IDC forecast. In 2008, Linux PCs are expected to account for less than 4 percent of unit shipments in the Americas and more than 9 percent in the other two regions.
Less than two weeks ago, IDC forecast the. That's less than the $11 billion forecast in the newer study, chiefly because IDC counted money in a slightly different way.
In the earlier forecast, using IDC's standard methods, the researchers count a Linux server sale only if that's the primary operating system. In the newer study, IDC accounted for servers that run Linux alongside other operating systems, Gillen said. For example, with a mainframe on which Linux occupies half its computing capacity, half the cost would be allocated to Linux.
Linux is most widely used on servers using x86 chips such as Intel's Xeon and Advanced Micro Devices' Opteron, but it also is supported on IBM's mainframes and Power processor based systems and on servers from HP and others using Intel's Itanium processor. In addition, hardware and software options available today let x86 servers be split so they can run Windows and Linux.