Deploying a new operating system to desktops across an organisation can be a time-consuming, expensive and painful process, especially if it means physically commandeering every employee's workstation. That's why most companies try to milk their existing investments as long as possible -- and the reason IT pros might have winced at news of Vista and the thought of rolling it out.

Fortunately, many third-party tools from companies like Symantec and Altiris do a good job of automating desktop migration -- to get you through what amounts to a "major life event" in IT. Microsoft itself is getting into the act with the release of Solution Accelerator for Business Desktop Deployment (BDD) and the Operating System Deployment (OSD) Feature Pack for Microsoft Systems Management Server (SMS).

Here's what we've learned about BDD from our work with customers.

Zero-touch refresh
BDD, which can be downloaded for free, provides guidance and a set of scripts designed to reduce the cost and complexity associated with creating and managing a corporate-standard Windows XP image.

It gives administrators a set of best practices to follow when it comes to such tasks as integrating service patches, hot fixes, registry settings and security policies. With a script to follow, you can save the time required when working off a blank canvas.

In the case of a remote site with slow network connectivity to the central SMS site or where a distribution point isn't present, the administrator can cache an operating system package on target computers by configuring Download and Execute on the image package -- or manually copying the operating system package content to a local network share. In either case, the operating system package can be modified to pull the files from a local source instead of downloading several gigabytes of data through a slow connection during deployment.

BDD includes a zero touch deployment model that uses Microsoft Systems Management Server with OSD Feature Pack. OSD is intended to help organisations perform zero- and light-touch operating system refreshes at both local and remote sites.

OSD captures Microsoft Windows XP images using Windows Imaging Format (WIM), a new file-based format that will be the standard in Windows Vista. WIM lets you deploy operating system images alongside existing files or folders on the system drive, something that's not possible with earlier sector-based image formats.

Upgrading now or later
Although you can't modify WIM files directly today, Microsoft plans to address this limitation by introducing a command-line utility called xImage that will ship with the upcoming release of Windows Vista.

For example, you'll have command-line capability to add or change files in an existing server image as well as deploy an image from a network share, DVD or from second partition on the target computer. OSD supports these deployment methods today, but some assembly is required.

To be sure, upgrading isn't painless, and many companies wait as long as possible to do it. But does it make sense for companies running, say, Windows 2000 to hold off for Vista's release? You'll want to consider these tool sets and then weigh other benefits and challenges of upgrading now versus later.

Operating system deployments are highly visible projects because they directly affect every user. Although OSD has built-in support for Microsoft's User State Migration Tool, you can easily integrate other third-party tools like PC Transplant from Altiris, or, depending on your IT environment, you can also use home-grown scripts.

Create an action plan
Here are three things to keep in mind before embarking on an operating system deployment with BDD and OSD:

1. Planning is crucial. You need to have a clear understanding of your environment. Does all your hardware support Microsoft Windows XP, or will you need to do a hardware upgrade before deployment? Identify department- or site-specific applications that need to be installed as part of the imaging process.

2. Know your bandwidth limitations. Determine upfront whether it's best to cache images locally on desktops (the slow-link scenario given above), store them on a network share (when a distribution point isn't available) or have Microsoft SMS download a server image in real time during deployment.

3. Allocate enough space to store user data. Knowing what kind of data to pull from the user desktop and where to store it is crucial. You don't want to run out of storage space in the middle of a deployment.

Whether you're contemplating an operating system upgrade now or later, there are proven tools that can help alleviate the pain of desktop deployment.

Christopher Burry is technology infrastructure practice director and a fellow at Avanade, a Seattle-based integrator for Microsoft technology that's a joint venture between Accenture Ltd. and Microsoft. Rafael Dominguez is a systems engineer and a Microsoft Certified Professional at Avanade. Comments or questions can be sent to [email protected].