Gartner estimated in April that the installed base of Linux PCs will grow this year by 16% to 19.4 million worldwide. In contrast, the installed base of Windows desktops will grow more slowly but on a much bigger base: a projected 11.4% year over year to 1.05 billion PCs. Of that number, 311 million are Vista. Apple (AAPL) is doing a little better: Macs with the Apple operating system will grow by 11.6% to 28.2 million.
While total installed OS-equipped PCs are expected to grow at 11.8% in 2009, Gartner sees Linux PCs growing by just 10% to 21.4 million, vs. 11.7% for Windows to 1.18 billion. Mac OSs are projected to grow by 17.1% next year to 33 million.
"We are starting to see a lot of interest from very sizeable customers" in the emerging markets of India and China for a viable alternative to Windows on the desktop, John Dunderdale, IBM vice president of sales for Lotus, said in an interview.