By the time you read this, Microsoft will have released Windows Vista Release Candidate 1 (RC1), the final major milestone of this product before it's shipped to manufacturing. Vista RC1 is a near feature-complete version of Microsoft's next OS release and it offers major functional, compatibility, and fit-and-finish improvements compared with previous prerelease Vista versions. Therefore, now is an ideal time to start your Vista evaluations, if you haven't already begun doing so. Here's what you need to know about Vista RC1.

It Just Works
Previous prerelease Vista versions amounted to a study in frustration. Although they offered an interesting peek at features that Microsoft intends to ship in the final version, many of those features were only partially implemented and were quite buggy.

Indeed, in the days leading up to RC1, numerous analysts and online pundits called for Microsoft to delay the Vista release, citing the low quality of Beta 2 and other prerelease Vista versions as proof that a healthy product would never make it on time.

But now a funny thing has happened. RC1, although certainly not free of bugs, is notably more refined than previous versions. Software applications and hardware devices that never worked before have suddenly begun working. Infamous and long-lasting bugs, including ones that wouldn't let the user delete icons from the desktop, have suddenly been eradicated. With RC1, customers will finally see a version of Vista that approaches and even surpasses the quality level they've come to expect from Windows XP. Users will now be able to actually focus on the new OS's features and capabilities.

Functional Improvements Over XP
The Vista RC1 experience is essentially very similar to that of XP: There's a desktop, a Start menu, a taskbar, and a tray-notification area. However, the display subsystem has been completely revamped, so users with mainstream desktops will likely see a graphical treatment, called Aero, which surpasses anything in XP. Aero isn't just eye candy, however. Vista RC1 includes real productivity enhancements, such as a more logical Microsoft Internet Explorer (IE) structure with Microsoft Office Live icons that let you view in-place previews of the content they contain.

Vista RC1 includes a slew of new applications, most of which have no XP counterparts. Windows Calendar finally provides users with a free and capable calendaring application that's based on Web standards, making it easy to publish and subscribe to coworker's schedules. Windows Meeting Space will prove a boon to knowledge workers who want to collaborate in real time by using a wireless network. If no network is available, Meeting Space will set up a new ad-hoc network of its own so that users can keep working together.

Vista's amazing new backup and recovery tools will make it a snap to back up files or even image entire hard disks. Also, Windows-Server 2003's Previous Versions feature—previously-called Volume Shadow Copy—has been ported to the Vista client, letting users recover older document versions without needing to call the Help desk. (Previous Versions also works with server-based files, if you're using Windows 2003 or later.) And a new version of Microsoft Windows Update seamlessly integrates with the Microsoft Update service or your own software-updating mechanism, ensuring that your systems are always up-to-date.

Most Security Improvements
Microsoft made great security strides in both XP Service Pack 2 (SP2) and Windows 2003 SP1, but Vista includes the most security improvements that Microsoft has ever added to a single Windows product version. User Account Control (UAC), once the bane of previous beta releases, is suddenly quite usable, thanks to a more subtle use of UAC-notification dialog boxes and less frequent interruptions. This feature helps users understand when they might be running a task that could potentially harm the system. Naturally, enterprises can turn off the feature, use it as-is, or ensure that users are running with standard user accounts and thus won't be able to cause any damage.

Microsoft has also incorporated XP SP2's Windows Security Center feature into Vista but has substantially improved it. This time around, Security Center provides security monitors to the firewall, automatic-updating, and malware-protection checks that XP SP2 offered. These monitors include Internet security settings—configured through IE 7.0—and the aforementioned UAC.

Speaking of IE 7.0, the latest version of Microsoft's maligned Web browser is much improved, and the version shipping with Vista is the best yet. All versions of IE 7.0 (including standalone versions that will ship for Windows 2003 SP1, XP SP2, and XP Professional x64 Edition) will include security controls for antiphishing, malicious ActiveX controls, International Domain Name (IDN) spoofing, and more. Most important, in Vista, IE 7.0 runs at a privilege level that's lower than that of any other application, and downloads are sandboxed in a private area of the hard disk where they can't do any damage. This feature is unique to Vista.

Are Your Systems Compatible?
If you're interested in evaluating Vista RC1 for your organization, I advise you to examine the features that I've mentioned here, as well as the new deployment tools, which use large image files rather than massive collections of small files. Because of Vista's componentized nature, you'll no longer need to maintain separate installation images for your hardware and language configurations.

You'll also want to pay attention to hardware, software, and intranet compatibility problems. Although Vista RC1 is a major improvement over previous beta versions, Vista RC1 probably won't be completely compatible with all the hardware you're using. Now is the time to determine whether your devices will be supported in the future.

Likewise, Microsoft has done a lot of work to ensure that most XP-based-applications function properly in Vista, but problems will remain, especially with custom and in-house applications. You'll also need to test intranet sites and other Web portals against IE 7.0, which offers some major changes compared with IE 6.

Finally, be sure to check your existing PC configurations against Vista RC1 to determine whether you'll have to update your PC systems at the same time as the OS. Unless your hardware is four years old or more, you'll probably discover that Vista RC1 works just fine. If you're nervous about training costs, you can also run Vista RC1 in its Classic mode, which is similar to running Windows 2000.

What You Really Need to Know
One of Microsoft's Vista goals was to convince its corporate customers not to wait for Vista SP1. Interminable delays and bad press have all but doomed that possibility, yet once again Microsoft will see its next OS float or sink on its merits.

Microsoft's plan is to ship Vista SP1 alongside Longhorn Server, which is currently set to ship in the second half of 2007. Vista SP1 will be a major upgrade—the most momentous service pack release Microsoft has ever shipped—because it will include major kernel changes that will bring Vista technologically up to speed with the kernel in Longhorn Server. Given the schedule, it's fair to assume that Microsoft plans to ship other major new functionality in Vista SP1. Either way, one might logically point to Vista SP1 as the "true" final release of Vista and the one that many organizations will want to wait for.

Recommendations
Vista is roaring like a freight train toward completion, but there's no reason why enterprises need to migrate to the new system any time soon. You should weigh your needs versus Microsoft's plans to significantly upgrade the Vista kernel less than a

year after it ships the initial Vista version. My advice is to wait—unless you're running Windows clients that predate XP SP2: Vista's security enhancements are a huge improvement over what's available in older Windows versions, and they're reason enough to consider upgrading quickly. Whatever your plans, a migration is almost inevitable. The only question, of course, is when.

x64 Corrections
When a Microsoft Fellow tells me I've screwed up in my descriptions of Microsoft technologies, I tend to sit up and take notice. So, when Mark Russinovich—of Sysinternals fame and now a Microsoft employee—contacted me about my article "What You Need to Know About Windows Vista x64 Versions' Unique Security Features" (August 2006, InstantDoc ID 50522), I knew readers would want the scoop. First, Russinovich says that Address Space Layout Randomization (ASLR), which Vista Beta 2 introduced, works with both 32-bit and 64-bit versions of Vista. That's not how the feature was first described to me, but I apologize for the mistake.

Second, Russinovich noted that hardware-enforced Data Execution Prevention (DEP) is actually available on 32-bit systems as well, assuming the PC is based on an AMD processor with no-execute (NX) page protection or an Intel processor with the Execute Disable Bit functionality. Third, PatchGuard debuted in the x64 versions of Windows 2003 and XP Professional x64 Edition, though this feature is unique to x64 systems, of course.

Finally, Russinovich told me that kernel mode driver signing is required for x64 versions of Vista for accountability rather than reliability reasons. The idea is that malware authors won't be able or willing to obtain digital signatures because their code will be traceable if they do. I have no contention with that point, although I'd mention that Vista x64 drivers are harder to hack, and thus will be more reliable as a result, than their 32-bit cousins.