To get ready for the inevitable questions from clients and for my own edification, I’ve been looking at what the pending release of Windows Vista SP1 will mean to them and to me.

Microsoft has been claiming that SP1 will improve the performance and reliability of Vista, along with significantly changing the behavior and capabilities of different components of the OS. Although I’ve had few problems with Vista, I'm not opposed to anything that improves performance as long as the system remains stable, so I’ve been looking forward to the service pack release.

Like Windows XP SP2, which in the long run brought benefits to XP users, the Vista SP1 installation should be carefully evaluated before being deployed. You'll need to identify changes and prepare your users, and therefore you'll need to prevent Windows Update from pushing SP1 to your Vista users until you're ready. At this point, there are no tools to make this configuration change, such as were made available for XP SP2, but it's reasonable to presume such tools will be available when the service pack is in general release.

Though Microsoft expects the service pack to be deployed primarily via Windows Update and Windows Server Update Services (WSUS), a single standalone version will be available that works with all versions and all supported languages for Vista. To give you some idea of how significant the service pack changes are, this standalone deliverable will be about 1GB in size and replaces such a significant percentage of the OS files that it won't be possible to update any disk images you are currently using for deployment.

IT will need to create new disk images from a new baseline system--one that has been upgraded with SP1 and had all of the required application and configuration changes made to it.

And while it's unlikely to be an issue for any recently built computer running Vista, the installation itself has a very large disk footprint: over 7GB for the basic x86 installation. I haven’t actually tried it yet, but I’m sure that space is needed on the boot partition of the system being upgraded.

It’s actually worse with the x64 version of Vista SP1: The disk footprint is over 12GB. For me, that's a problem, as I have a few x64 test systems set up that have fairly small (20-30GB) boot partitions. Depending upon the applications that I currently have configured, they won’t have the necessary 12GB available to install the service pack.

But don't be too concerned about giving up a large amount of storage to the service pack upgrade--Microsoft states that most of the space used for the installation is released when the update is complete.

Vista SP1 is going to be a big deal. If you're supporting users on this OS, don’t let it take you by surprise.