After many months of beta testing, Microsoft finally shipped Windows 7 on 22 October 2009. Just days later, Apple stated that their Boot Camp software (which allows Intel-based Macs to boot into either Mac OS X or Windows) would be updated to support Windows 7 by the end of the year. Up to that point, Boot Camp supported only Windows XP (SP2 or later) and Windows Vista, and although some people had limited success installing Windows 7, a number of bugs and compatibility issues were reported. Apple has finally made good on the promise of Windows 7 support in Boot Camp - albeit a few weeks late and with a number of caveats.

First, before you can even download the updated software, you must decide whether you'll run the 32-bit or 64-bit version of Windows 7 - Apple offers a different Boot Camp update for each. Boot Camp 3.1 for Windows 64 bit is a mere 275 MB download, whereas Boot Camp 3.1 for Windows 32 bit weighs in at 381 MB. Either version lets users install the Home, Premium, or Professional edition of Windows 7 on a separate partition of their Mac's internal hard disk. In addition, the updates resolve unspecified issues with the Apple trackpad, add support for the Apple wireless keyboard and mouse, and disable the red digital audio port LED on notebooks when it's not in use.

Second, for reasons Apple hasn't explained, not all Intel-based Macs can run Windows 7 in Boot Camp; those that can't are still limited to Windows XP or Vista. Apple's list of unsupported models includes certain iMacs, MacBook Pros, and Mac Pros introduced in 2006; all newer Macs should be able to run Windows 7 just fine.

Third, users who previously had Vista installed in Boot Camp and now want to upgrade to Windows 7 must install the new Boot Camp Utility for Windows 7 Upgrade (after the Boot Camp 3.1 upgrade but before installing Windows 7). Without this update, the Mac volume (which appears as read-only under Vista) may fail to unmount during the upgrade, resulting in an obscure error message.

And finally, certain Macs need one or two additional updates to work with Windows 7 in Boot Camp (which must also be applied before installing the new operating system):

• Owners of a late-2009 21.5-inch or 27-inch iMac must download and install the iMac Late 2009 Windows 7 Drivers, which prevent the screen from turning black during the installation of Windows 7 because the system lacks the necessary graphics and Bluetooth drivers. The update is 104 MB, and is available either via Software Update or as a stand-alone download. But note that installation is unusually tricky. Users must download the update, copy it to an MS-DOS-formatted USB device, and insert that device into the computer's USB slot before installing Windows 7. More information regarding this update is available via Apple's Web site.
• Owners of iMac models with the Nvidia GeForce 7300 or 7600 GT graphics cards, or Mac Pro models with Nvidia GeForce 7300 GT or Quadro FX 4500 cards, must install the Graphics Firmware Update 1.0 (iMac and Mac Pro). Apple doesn't say exactly why, or what this update does, but it's only 1.2 MB.

Of course, none of these updates are necessary if you want to run Windows 7 using virtualization software such as VMware Fusion, Parallels Desktop, or VirtualBox. Given the convenience of running Windows this way - no reboot required to switch operating systems - virtualization is increasingly the more logical technique.