Tallies kept by the U.S. government's computer security group show that Linux and Unix operating systems faced nearly three times the number of vulnerabilities in 2005 than did Microsoft's often-maligned Windows.

In the US-CERT (United Stated Computer Emergency Readiness Team) year-end vulnerability summary, Linux/Unix accounted for a whopping 2,328 vulnerabilities, about 45 percent of the 5,198 total.

Windows, on the other hand, sported just 812 vulnerabilities during the year, said US-CERT, or 16 percent of the total.

Another 2,058 vulnerabilities affected more than one operating system.

Although US-CERT didn't break out Mac vulnerabilities in a separate category, the Linux/Unix section listed more than 25 attributed to the Apple Computer operating system.

The end-of-year vulnerability score should be taken with a grain of salt, however, since US-CERT doesn't filter out updates (so one actual vulnerability can be counted numerous times) nor does it break out individual vulnerabilities from warnings that cover multiple bugs (as in the many Mac OS X vulnerability listings).