Windows 8 shows market share gains, but still behind predecessor SAN FRANCISCO, May 1 (UPI) -- Windows 8 is advancing in the desktop operating system market but has yet to match the milestone Windows 7 had reached at the same stage, a tracking firm says. Microsoft's latest OS took in 3.8 percent of all traffic captured by Web tracker Net Applications in April, CNET reported Wednesday. That put it in fourth place among all desktop operating systems, behind Windows 7, Windows XP and Windows Vista and slightly ahead of Mac OS X 10.8, Net Applications said. The Windows 8 numbers put it far behind Windows 7 as the same point in their release window, it said. Both were release in October of their respective years, but by April 2010 Windows 7 owned nearly 12 percent of the OS market tracked by Net Applications. Microsoft is already working on a Windows 8.1 for release later this year, CNET reported.