Though Microsoft has discussed the Longhorn client extensively, it has said very little to date about Longhorn Server, the Windows Server version that will arrive in early 2007. Longhorn Server will extend the technologies found in Windows Server 2003 with Service Pack 1 (SP1) and Windows Server 2003 Release 2 ("R2"), the latter of which is due in October 2005. And like its predecessors, it will offer an evolutionary, rather than revolutionary server platform that builds on past technologies while providing new functionality. Specifically, Longhorn Server won't be completely re-architected or be rewritten in managed .NET code. However, it's likely that Microsoft will dramatically change the Windows Server kernel in this release, breaking compatibility where necessary in order to deliver dramatic new features or new levels of security. Here's what I know about Longhorn Server so far.

High-level view

Today, Windows Server 2003 with SP1 represents the most secure and reliable operating system that Microsoft has ever created. Certain tools, like the Manage Your Server front-end, the Security Configuration Wizard (SCW), and the various administration tools in Windows Server 2003 Small Business Edition, hint at the ways in which the software giant seeks to make server computing both more powerful and easier to use and manage. With Longhorn Server, we can expect more of the same: Microsoft will attempt to make this release the highest quality version of Windows Server ever shipped, with versions of the product that are custom-tailored to specific businesses, including small and medium businesses (so expect a Windows Server Medium Business Edition), high performance computing, and storage, among others.

And, as with the Longhorn client (what I think of simply as "Longhorn"), Microsoft wants to make Longhorn Server its (server) platform for the next decade. So the company is willing to make critical breaks with the past where needed--particularly with compatibility--if that ensures that Longhorn Server is as safe, reliable, and useful as possible. This is a marked change in philosophy at Microsoft. In the past, compatibility trumped most other concerns. Today, security and reliability are more important than compatibility.

Unlike the Longhorn client, however, Longhorn Server will not include the Aero user interface, which is superfluous on a server product. The core Longhorn pillars--Avalon, Indigo, and WinFX--will of course be present, however.

Specific features

Many people have been wondering what features Microsoft will include in Longhorn Server. Some features have already been revealed. For example, Longhorn Server will include the "Bear Claw" implementation of Terminal Services, which frees users from dealing with remote sessions and instead lets them access individual remote applications as if they were running directly on the local system. This feature is called application publishing. Longhorn Server will also include full-feature network quarantine functionality that prevents notebooks and other remote computers from connecting to an enterprise's internal network until they meet the requirements of that organization's security policies. If they don't, the remote machines are quarantined in a safe portion of the network and provided with the software updates they need. Only then, will those machines be allowed to access other internal resources.

Longhorn Server will also include Internet Information Services (IIS) 7.0, a major new version of Microsoft's Web server. IIS 7 will be componentized for security and include much more graphical administration tools. Longhorn will also ship with Windows SharePoint Services (WSS) 3.0, offering more sophisticated collaboration features.

Many Longhorn Server features will be first implemented in the Longhorn client (see my Road to Longhorn showcase for details). For example, Longhorn Server will include Longhorn's hot-patching feature, which lets all non-kernel updates occur without the need for a system reboot. This feature will cut down server reboots by up to 70 percent, according to Microsoft. And like Longhorn, Longhorn Server will include support for Limited User Accounts (LUAs), preventing administrators from inadvertently harming a system, as each potentially dangerous operation will require an in-place logon.

And Longhorn Server, like Longhorn, will be fully componentized, making it easier for administrators to roll out servers that only include the functionality they need. These servers will be more secure as a result: A core server OS component, called Server Foundation ("MinWin"), will provide minimal server OS functionality and will be used as the basic building block for job-specific server implementations and even other Longhorn Server editions. Server Foundation can be extended with a number of server roles--mostly networking services like DHCP, DNS, and Active Directory) that add functionality to the base component. Longhorn will also include the image-based setup and deployment tools that will first ship with Longhorn.

It's unclear whether Longhorn will include WinFS, though Microsoft internal documentation notes that the release will include a new "transactional file system and Registry."

Some Longhorn features will be evolutionary improvements over features we see today in Windows Server 2003 with SP1. One typical example: A new roles-based management tool will combine the functionality of Manage Your Server and the Security Configuration Wizard into a single front-end for configuring both the functionality and security of your servers. And because Longhorn Server is an evolutionary release, it will support Windows Server 2003 drivers.

Longhorn will also include next-generation versions of the Feature Packs Microsoft shipped for Windows Server 2003, including a new rendition of Windows Rights Management Services (Windows RMS).

Timing and delivery

Longhorn Server will ship approximately 6 to 9 months after Longhorn, or in early 2007. This target date is in keeping with Microsoft's two year server release cycle: Windows Server 2003 shipped first in 2003, followed by Windows Server R2 in 2005. And yes, Microsoft has already committed to an R2 release of Longhorn Server, which is due in 2009. The next major Windows Server release after Longhorn Server, dubbed Blackcomb, is thus due in 2011.

Conclusions

Longhorn Server is very much a work in progress, and no doubt we'll learn a lot more about this product over time. My guess is that Microsoft will begin publicly revealing more Longhorn Server product features in either April (at the Windows Hardware Engineering Conference, or WinHEC, trade show) or in September, at the Professional Developers Conference (PDC) 2005. However it does so, I'll update this document to reflect any new information when it becomes available.