An XP-to-Vista migration may not be in the cards for everybody, but at this point, the jump to Windows 7 is inevitable for XP users. A recent report from IT research firm TAC (The Advisory Council) highlights the most efficient ways to roll out Windows XP to Windows 7 upgrades. One key message: if you are not upgrading in 2009 you should at least be planning to do so.The report, entitled "Cutting Through the Nonsense About Windows Vista, Windows 7", also touches on a subject that Microsoft probably wants kept quiet: The migration to Windows 7 will not be much different than to Vista, the report's author, Peter Schay, concludes; the two OS's share the same software compatibility issues, interface features and hardware requirements (though Windows 7 is reportedly much less resource-intensive).It's no secret that Microsoft is trying to disassociate Windows 7 from Vista, despite the OSes sharing the same code base. \n\nWindows 7 has good timing and marketing on its side, Schay says . The Windows 7 beta has been getting positive reviews and the release of the OS, likely to happen some time in the second half of this year, will coincide with companies' hardware refresh cycles that have been stretched to four or five years because of the economic downturn.The report from TAC goes on to offer advice for XP users facing an upgrade, including lessons from Vista's failure, thoughts on Windows 7's potential and a look at the realities of switching to Linux or Macintosh.Thin Line Between Vista and Windows 7 Windows Vista failed to get the initial adoption rates that Microsoft hoped it would, especially at enterprises. Vista adoption has improved since Microsoft released Vista service pack 1 (SP1) in February, but even two years after its release Vista still only has 21 percent market share, according to Web metrics company Net Applications.The TAC report cites the usual suspects for Vista's troubles: software application incompatibility, beefed up security at the expense of compatibility, intrusive UAC pop ups and changes to the user interface. Windows 7 may be a new brand name, but all of the reasons XP users put off Vista apply more or less equally to Windows 7 too, Schay writes."If your application software is incompatible with Vista, then it will be incompatible with Windows 7. While there will be incremental performance improvements in Windows 7, the hardware requirements are the same as for Vista," he writes.XP users will have the benefit of learning from other people's past Vista headaches and should start upgrading to Vista and\/or Windows 7 compatible application software now even if they won't actually be migrating for a few more years, the TAC report advises.Don't Think a Linux or Mac Migration Would Be EasierSome pundits and bloggers believe that Vista's bad reputation and slow acceptance will lead to a wave of converts to Linux or Mac OS. But the TAC report deems this notion "naive at best, and disingenuous at worst."Again the reason is lack of application compatibility, cites the report. "Neither Linux nor Macintosh brings anything to this party," writes Schay, adding that a Linux or Mac OS migration would be a much greater effort than a Vista\/Windows 7 upgrade and should only be done if there are motivations at play other than hardware and software compatibility.Schay concedes that Linux has Wine, the free Windows compatibility tool, and Macs can run Windows as a virtual machine, but he writes that these options "add complexity for both the user and IT, and still leave the issue of eventual end-of-support for XP on the table."\n\nWhether Upgrading to Windows 7 or Vista, Start NowThe TAC report emphasizes that eventually Microsoft will pull the plug on Windows XP, just as it did with Windows 98. So what should businesses do about upgrades from XP in 2009? Plan, plan, plan.The report advises that if you have a Vista migration underway you should continue it, because Vista and Windows 7 will co-exist well for a smooth migration later. If you have not started a Vista migration plan, the report says, Windows 7 will be available soon enough that Vista can be skipped.But author Schay offers a caveat: Don't expect Windows 7 to be an easier migration because it has a different name."Skip Vista with the understanding that it isn't going to save you from the work and cost of upgrading your software applications to be Windows 7 compatible," he writes.