Windows 7 arrived two weeks ago and so far it's selling quite well. With Mac OS X 10.6 becoming available less than three months ago, and Ubuntu 9.10 arriving last week, we feel it's a good time to start watching the market share for operating systems, in addition to our monthly posts on browser market share. At this point in time, Windows continues to dominate with more than 90 percent of the market, Mac OS is above the five percent mark, and Linux is just under one percent. In October, Windows was the only operating system not to show positive growth.

Between October and September, Windows dropped 0.25 percentage points (from 92.77 percent to 92.52 percent), Mac OS climbed up a sizeable 0.15 percentage points (from 5.12 percent to 5.27 percent), and Linux edged forward 0.01 percentage points (from 0.95 percent to 0.96 percent). Windows' drop is worth noting given that it occurred in the month that Windows 7 was released, but November may show something different given that it will be a full month of sales of the operating system. Still, Windows 7 did quite well; it managed to pass Linux, Snow Leopard, and even both of their shares combined (2.13 percent versus Windows 7's 2.15 percent):

Source: Net Applications

You can see the market share pie for October 2009, according to Net Applications, at the top of this post. The graph just above shows how things at Ars are different, but not as significantly as when it comes to the browser market: our Mac OS share is five times greater than in the rest of the world, almost six if you count the mobile space as well. Linux also commands six times more of the market. Despite this, more than half of our users are on Windows. The release of Windows 7, Snow Leopard, and Karmic Koala should keep things very interesting well into next year.