For many years, the Windows world was divided into two camps: the so-called "consumer" editionsWindows 95, 98, and Meaimed at individuals and home office users, and the "business" editionsWindows NT and 2000aimed at the corporate market. With the release of Windows XP, Microsoft merged these two streams into a single code base. However, that didn't mean the end to having multiple editions of the operating system. In fact, XP ended up with six major editions: Starter (for users with low-cost PCs in emerging markets outside North America), Home (individuals), Professional (corporate users and the SOHO crowd), Professional x64 (the 64-bit version for power users), Media Center (multimedia users), and Tablet PC (with digital pen support for Tablet PC users). Many people found the existence of so many versions of XP confusing, and it certainly was a head-scratching situation for anyone not versed in the relatively subtle differences among the editions.

Given this widespread confusion, you would think that Microsoft would simplify things with Windows Vista. After all, a case could be made that the reason so many people did not upgrade to XP was that they simply were not sure which edition they should purchase. So no one would blame you for thinking that the road to Vista is going to be straighter than the twisting XP path.

In the end, Vista will ship with the same number of versions as XPsix in allalthough Vista's versions will be configured completely differently than XP's. First, the home market will see two editions:

• Windows Vista Home Basic This edition will be made available in North America and other developed nations, and it represents the simplest Vista option. The Home Basic Edition is aimed at individuals using their computer at home who want security without complexity. Home Basic includes Windows Defender, Windows Mail with its antispam features, Internet Explorer 7 with its antiphishing features and protected mode, the improved Windows Firewall, the revamped Security Center, and Vista's enhanced parental controls. It will also feature Windows Media Player 11, Windows Movie Maker, Windows Photo Gallery, Windows Calendar, Windows Sidebar, Windows Search, the Games Explorer, partial support for the Mobility Center for notebook users, and basic networking (wired and wireless). However, Home Basic will not support the new Aero shell.

• Windows Vista Home Premium This edition includes everything in Home Basic, plus the Aero shell, Media Center, support for Tablet PCs, Windows Collaboration, Windows DVD Maker, scheduled backups, DVD ripping and authoring capabilities, the Mobility Center for notebook users, and advanced networking capabilities (such as ad hoc peer-to-peer networks and multiple-machine parental controls). This edition is aimed at networked household, multimedia enthusiasts, and notebook users.

The business market will also see two editions:

• Windows Vista Business This edition is analogous to Windows XP Professional and includes the same corporate features as XP Pro: support for domains, multiple network protocols, offline files, Remote Desktop, file and folder encryption, roaming user profiles, and group. Vista Business also comes with the Aero shell, Internet Information Server, Windows Fax and Scan, support for Tablet PCs, and the full Mobility Center. This edition does not come with Media Center, Movie Maker, and DVD Maker. In short, it's a no-nonsense OS for the business professional.

• Windows Vista Enterprise This edition is optimized for corporate desktops. It includes everything that's in Vista Business, plus features such as Windows BitLocker (drive encryption for sensitive data), Virtual PC Express, Multilanguage User Interface (MUI), and Subsystem for UNIX-Based Applications (SUA). It also allows IT personnel to deploy the OS in different languages using a single disk image. Note, however, that Enterprise Edition will be made available only to Enterprise Agreement (EA) and Software Assurance (SA) volume-licensing customers. (Or, of course, you can just buy the Ultimate Edition, which I discuss next.)

Bestriding the canyon that exists between the home and business editions is an everything-but-the kitchen sink version:

• Windows Vista Ultimate This edition comes with all the features of the Home Premium and Enterprise editions. It also offers enhanced game performance, access to online subscription services, custom themes, and enhanced support.

Here's the sixth Vista version:

• Windows Vista Starter This is a stripped-down edition of Vista that will be made available only in emerging markets. It's designed for low-cost PCs and is optimized to run on machines with relatively slow CPUs and small memory footprints. This means that the Starter Edition won't support features such as the Aero shell, networking, image editing, and DVD burning. As with XP Starter Edition, Vista Starter Edition will be limited to an 800x600 display and won't allow users to open more than three programs or three windows at once.

In addition to these editions, there will be OEM equivalents for all versions, as well as 64-bit versions for everything except the Starter Edition. Finally, Microsoft will also make available special versions of Vistaa Home Edition and a Professional Editionthat are customized for Europe to satisfy antitrust legal obligations in that region, which means these editions come without Microsoft's media features, including Media Player and Media Center.