Last week, Microsoft unveiled the latest rendition of its Windows Services for UNIX (SFU) tool, version 3.5, which features several important technical improvements. But the most impressive aspect of this version is the cost. For the first time, Microsoft is licensing SFU to its Windows customers for free, marking yet another case in which a previously separate product was rolled into the core Windows product, as was the situation with Microsoft Internet Explorer (IE) or the Windows Media technologies. Whether or not you believe this combination to be the result of competition from Linux, as I do, the freely licensable SFU 3.5 will be a boon to any enterprise that wants to migrate legacy UNIX applications to Windows or to better integrate Windows, UNIX, and Linux in a heterogeneous environment. Recently, I spoke to Dennis Oldroyd, a director in the Windows Server Group at Microsoft, about SFU 3.5.

At its heart, SFU is an interoperability tool designed to integrate various Windows versions (Windows Server 2003, Windows XP, Windows 2000 Server, and Win2K Professional; Windows NT 4.0 isn't supported in this release) with UNIX and, increasingly, Linux. SFU includes a UNIX application runtime environment that's based on Interop Systems' Interix technology and that lets you run UNIX applications and scripts on Windows machines and support UNIX technologies such as NFS and Network Information Service (NIS). "Very few of our customers have pure Windows environments," Oldroyd said. "Instead, it's a mix of Windows and UNIX, or Windows, UNIX, and Linux. In these businesses, interoperability is a key concern; \[businesses\] want to leverage directory services and files servers across those platforms, and they want to do so without having to buy a lot of new software."

SFU lets customers perform various interoperability tasks, such as authenticating UNIX and Linux users against Active Directory (AD); share resources across all platforms with appropriate user privileges handling and transfer legacy UNIX applications from expensive, proprietary, RISC UNIX hardware to more economical and familiar Windows machines, then run those applications on Windows. The environment also provides the familiar tools that UNIX developers, IT professionals, and administrators expect, so you'll see familiar C and Korn shells, applications, and command-line utilities such as gcc, make, emacs, vi, sendmail, and ftp. SFU also includes Perl 5.6.1 and ActiveState's ActivePerl to ease migration of UNIX administration scripts to Windows.

When you consider the task of moving legacy UNIX applications to a cheaper platform, Linux is the obvious choice. However, Microsoft contends that SFU on Windows is actually a cheaper solution, and I guess you'd have to base any cost estimation on your enterprise's experience with various OSs. But with the move to free licensing in SFU 3.5, Microsoft is removing one of the remaining complaints. Although the previous version sold for $99 for each client and server installation, SFU is now arguably as cheap as (or cheaper than) a Linux solution, and the interoperability tools that SFU provides might give Windows-leaning enterprises all the incentive they need to make the move.

So what's new in SFU 3.5? "This version is an update from SFU 3.0 \[released in May 2002\]," Oldroyd said. "It has the same core functionality, but \[it's\] extended and improved with new features. It's still the most comprehensive UNIX migration solution out there, and it's offered and supported by Microsoft, which a lot of customers had been asking for. They told us to deliver this functionality so they could leverage their investment in their Windows back end." Specifically, SFU 3.5 includes redesigned and performance-tuned improvements to its NFS and NIS interoperability tools and Interix environment; support for UNIX P-Thread applications, enabling businesses to port over more complex, multi-threaded applications than was previously possible; better POSIX support; and the latest versions of X11 (X11R6.6) and many UNIX command-line utilities.

The first version to support Windows 2003, SFU 3.5 is more scalable than earlier versions and is cluster aware for greater availability. It also supports native Windows 2003 features such as Volume Shadow Copy Service (VSS), providing point-in-time copies of shared resources and backup and recovery capabilities.

To be fair, I haven't tested SFU 3.5 thoroughly yet, but I can say that it installs easily, although you need to place it in a path (like the default, C:\SFU) that contains no spaces. The default installation set is different for client and server OSs, so be sure to do a custom installation if you want to use tools such as ActiveState Perl or the Interix software development kit (SDK). Certain tasks, such as username mapping between UNIX and AD, the Telnet Server, and the NFS clients and servers, include standard Microsoft Management Console (MMC) plugins.

My gut feeling is that SFU 3.5 will likely appeal most to enterprises that have standardized on a Windows infrastructure but still maintain crucial legacy UNIX systems. Those companies that still run their core services on proprietary UNIX boxes will likely split evenly between Windows and Linux going forward, depending on their needs. Either way, however, SFU 3.5 is a killer deal and a product you should evaluate if you have UNIX migration or interoperability needs. You can download SFU 3.5 from the Microsoft Web site ( http://www.microsoft.com/windows/sfu ).