After the lengthy delays and angst that accompanied Windows Vista, the Windows 7 development cycle has been refreshingly straightforward and, dare I say, speedy. Microsoft issued a single pre-beta version of the OS to external testers in October 2008 (see my Windows 7 Preview), then shipped a single Beta release to the public in January (see my Windows 7 Beta Preview). By the end of April, you should have access to the one-and-only Windows 7 Release Candidate (RC) build, your last chance to evaluate where Microsoft is heading. Here's what you need to know about the Windows 7 Release Candidate.

Where the Release Candidate Fits

This is the final prerelease milestone for Microsoft's next desktop OS, and Microsoft will entertain only certain classes of changes to the OS, such as so-called "showstopper" bugs that prevent the system from working properly under certain conditions. The months-long gap between the Release Candidate and the final release (the so-called release-to-manufacturing or RTM milestone) exists solely so that Microsoft's partners and customers can get ready for the general availability of the OS. During this period, Windows 7 will be effectively locked down and "very few changes" will be made to the code, according to Microsoft.

[ Read Shipping Seven for an ongoing look at Windows 7 development ]

Changes Since the Beta

Microsoft described the Windows 7 Beta as "feature complete," meaning that it represented, largely, what Windows 7 would be in its final form. Then the company received an unprecedented onslaught of feedback in the wake of the public beta release and made the many changes that appear in the Release Candidate. These changes run the gamut from a handful of major functional updates to minor UI tweaks. Some of the more interesting changes include these:

Internet Explorer 8.0--and other features--are now user removable. Responding to a potential legal threat from European Union (EU) antitrust regulators, Microsoft has made Internet Explorer (IE) 8.0 removable via the standard Windows Features UI. But IE 8 isn't the only bundled application getting this treatment: Users will also be able to remove Windows Media Player, Windows Media Center, Windows DVD Maker, Windows Search, Handwriting Recognition, Windows Gadget Platform, Fax and Scan, and XPS Viewer as well.

User Account Control changes. With Windows 7, Microsoft has toned down UAC's need to constantly prompt the user for approval. However, after the widespread Beta release, testers weren't happy with some UAC functionality. Now, the UAC control panel will run as a high integrity process, ensuring that users are validated via a UAC prompt before they can make any changes. In addition, if users do change the UAC security level?functionality that wasn't present in Vista?they will again have to validate against a UAC prompt.

User experience changes. Windows 7 includes a modified version of the Vista desktop, simplified and enhanced with nicer visuals. For the Release Candidate, based on user feedback, the new Aero Peek effect is now an option in the Windows Flip (Alt+Tab) pop-up window. The Windows Key has been enhanced with new keyboard shortcuts aimed at power users. "Needy" applications that prompt users with flashing taskbar buttons are being made more visually distinct and, hopefully, easier to notice. Taskbar scaling has been improved so that the new-look taskbar can display more icons at a time. And Windows 7's new themes support is now easier to use and less likely to lose a user's changes.

Windows Explorer. The Windows 7 shell is being augmented in the Release Candidate with a tweaked UI, more obvious drag and drop in the new view styles, support for local (i.e., fixed) FAT32 disks, and a wide range of new icon view arrangements.

Windows Touch improvements. One of the big enhancements to Windows 7 is its globally-available touch interface called Windows Touch. Now Windows Touch has been augmented with an Aero Peek touch gesture and Show Desktop support. The onscreen touch keyboard now supports multi-touch for a more complete experience, allowing such key presses as Ctrl+C and Shift+[letter] for capitalization. And more natural right-click support has been implemented with a new multi-touch gesture.

Control Panel updates. The Windows 7 Control Panel has been enhanced in several ways. Administrators, IT pros, and other users can now lock a Windows 7 PC without first requiring a screensaver. And the High Performance power management scheme?hidden in Windows 7 Beta?is now more accessible, as it was in Vista.

Windows Media changes. While many feel that Microsoft should have simply removed Windows Media Player (WMP) from Windows 7 and used its arguably superior Zune software instead, the software giant created a new WMP version that actually provides some interesting new functionality of its own. In the RC, you'll see improved Internet radio playback, a cleaner Now Playing window, better power-management awareness, simpler device sync, and custom Jump List improvements.

Hardware support changes. A new Device Stage UI discovers and surfaces all of the functionality provided by a wide range of devices, printers, and other hardware, and the Release Candidate supports a wider range of hardware than did the beta. Additionally, Windows 7 offers better headphone support and increased reliability in the audio subsystem.

Performance. Finally, Microsoft has tweaked the performance of this surprisingly limber OS. The result is an OS that boots up, runs, sleeps, resumes, and shuts down much more quickly than its predecessor, Vista, and the beta release.

[ Preview some of these changes in Windows 7 Build 7048 Screenshots ]

Recommendations

Although your opinion of the Windows 7 Release Candidate won't affect the development of Windows 7 in a meaningful way once it is released, this build will give you a near-final look, which is crucial for planning. Windows 7 is very clearly "Windows Vista done right," and it looks like businesses that elected to skip Vista made the right decision. That said, there are few advantages of migrating from XP to Windows 7 (compared to migrating from XP to Vista), and even fewer for those actually considering upgrading from Vista to Windows 7. Overall, my advice is that XP-based environments should move to Windows 7 as quickly as possible, in order to take advantage of this system's usability, manageability, and security improvements. This is the most feature-packed and secure version of Windows yet, and if the RC build is any indication--and it will be--Microsoft clearly has a winner on its hands.

An edited version of this article appears in the May 2009 issue of Windows IT Pro Magazine as "Need to Know: Windows 7 RC." --Paul