FastStats Analyzer allows you to filter log file data by the operating system of the user accessing your web site.
For the most commonly used operating systems, just select them from the drop-down list marked Predefined operating systems. A special browser tag will appear below your selection.
Note: the operating system string is case sensitive (i.e. WinNT is different from WINNT).
OS filtering works by searching the identification text that the web browser provides to the web server. The name of the operating system the browser is running under almost always appears in this informational text (also called a browser tag). Different browsers specify different tags. For example, Internet Explorer will indicate that it is being used under Windows NT by including the phrase Windows NT in the browser tag, Netscape will include the phrase WinNT. To work with both browsers, you must search for the phrase NT.
Here is an example of the raw agent data outputted by Netscape and Internet Explorer:
Internet Explorer: "Mozilla/4.0 (compatible; MSIE 4.01; Windows NT)"
Netscape: "Mozilla/4.51 [en] (Win95; U)"
You can also manually edit and customize Analyzer's list of OS strings.