Guest said:
..... Given that the computers with XP on the whole are older than those with Vista, it seems logical that those with XP are being replaced more frequently than those with Vista. .....
Sorry, but that isn't true. Vista users are converting over to Windows 7 as expected (estimated for over a 2 year period for the conversion from the day Windows 7 was first released), while the majority of Windows XP users simply bought a second computer with Windows 7 or won it as a free prize (I've no complaints for a free computer).
Windows 7 End-User Estimate:
The estimate for the number of users to buy & use Windows 7, through the next 2 years (2009-2011) is equal to the estimated number of current Vista Users (22.23% which was rounded to 23% by Microsoft). In general, only Vista users are expected to convert to and use Windows 7 along side new computer buyers that have no choice (with a Microsoft product or current Microsoft shelved computers).
Aside from this original Microsoft estimate, if I take the current figures it would put it at 26.24% within two years from the date of Redmond's stats in Matthew DeCarlo's article. Microsoft doesn't expect Windows XP users to switch, but if they do, it's an extra bonus.
Data Storage Corporations and Network Corporations may purchase a second system with Windows 7, but are not throwing away their systems with Windows XP and/or Windows Vista and above all have stated that they, "Reserve the right to revert back to the so-called older system without notice." Obviously, in the event of severe bugs or other issues which is common with new products regardless of whom makes them.
I'm not going to restate disadvantages and advantages of Windows 7, and OS usages by global governments, which I've posted else where.
It should be noted that Windows Vista is 'Windows Version 6.0', that Windows 7 is 'Windows Version 6.1', and that Windows 7 uses the Windows Vista Core (eg. Windows 7 is basicly an upgraded Windows Vista).
The stats in Matthew Decarlo's article is accurate enough. Using the statistics he lists in his statements, here's the rest of the information that wasn't included in the article to complete the whole picture. (Note: You'll have to wait till Oct 2010 for a real annual figure comparison.)
OS Usage Stat (Oct 2009):
Windows XP: 67.55%
Windows 2000: 0.96%
Mac OS X: 4.71%
Linux: 0.96%
Other: 1.25%
OS Usage Median Stat (Oct 2009):
Windows 7: 2.18% *All Windows: 92.52%
Windows Vista: 22.23%
Windows XP: 67.55%
Windows 2000: 0.59%
Mac OS: 5.27%
Linux: 0.96%
Other: 1.25%
OS Usage by Top 500 Super Computers (Nov 2009):
Linux: 89.2%
IBM AIX 4.4%
Microsoft Windows HPC Server 2009: 1.0%
OpenSolaris: 0.4%
Mixed OS: 4.6%
Other: 0.4%