Executive Summary:

Microsoft released Windows Vista SP1 to customers under a strange, tiered schedule. The mystery behind SP1's release schedule is tied to the way Windows is developed internally: Both Vista SP1 and Windows Server 2008 were developed in lockstep and utilize the same code base. Here’s the story and the schedule, from beta users to retail to international users.

Microsoft took an unconventional path to deliver its first major update to Windows Vista. First, the company spent several months trying to convince its customers that SP1 didn’t even exist and might not be released. Then, in late summer 2007, the company came clean and released a series of SP1 beta versions. Throughout the end of 2007, the SP1 feature set changed as well: Microsoft made changes to Vista’s instant search functionality to appease Google, then changed the Windows Genuine Advantage (WGA) antipiracy functionality dramatically. Finally, in early February 2008, Microsoft completed SP1. But there was a final bit of controversy: Microsoft would release SP1 to customers under a strange, tiered schedule. Here’s what you need to know about the release schedule for Vista SP1.

What’s Going On with Vista SP1’s Schedule?
The mystery behind SP1’s release schedule is tied to the way Windows is developed internally: Both Vista SP1 and Windows Server 2008 were developed in lockstep and utilize the same code base. (So much so, that the first Server 2008 service pack will actually be SP2, allowing Microsoft to work on the next major updates to both Vista and Windows Server simultaneously.) Server 2008 has been in development for almost five years, and Microsoft spent much of the past year refining that release and improving its overall quality, reliability, and fit and finish.

Because they were developed together, Microsoft wanted to freeze development of Vista SP1 and Server 2008 at the same time. Vista SP1, however, had a much shorter development cycle than Server 2008, and late in the beta process, Microsoft’s beta testers discovered some device driver incompatibilities with SP1 that could cause customer PCs, which had worked fine with the original version of Vista, to not recognize particular hardware devices. While it’s unlikely that Microsoft will ever identify these devices specifically, my sources tell me that they are mostly networking oriented, and some are quite common.

To meet its arbitrary internal schedule, Microsoft released Vista SP1 to manufacturing alongside Server 2008 in early February 2008 but announced that it wouldn’t immediately release the update to the public, citing the mysterious device driver issues as the cause. Instead, the company said it would roll out SP1 to customers on a tiered schedule over the first half of 2008.

What’s the Exact Schedule?
Depending on how you choose to acquire Vista SP1, it should be available by the time you read this, or shortly thereafter. Here’s the schedule:

Beta testers. Those who participated in the Vista SP1 beta test received the code a week after Microsoft shipped SP1, on February 8, 2008.

Volume license customers. Corporate users who participate in Microsoft’s volume licensing programs received DVDs with an integrated version of Vista and SP1 in February. MSDN and TechNet subscribers. Developers and IT pros who subscribe to Microsoft’s MSDN and TechNet Plus services received Vista SP1 before the end of February.

Standalone downloads. The standalone versions of the SP1 code will be made available on Microsoft.com in mid-March.

Windows Update. Those wishing to upgrade an existing Vista-based PC to SP1 via Windows Update will be able to do so in mid-March 2008 or in mid-April 2008, depending on their hardware configuration. If you enable Windows Update to automatically download updates and do not have any of the affected hardware installed, you will automatically receive SP1 in mid-March. Otherwise, it will be mid-April.

Preinstalled on new PCs. New PCs with Vista SP1 will appear on store shelves “in the coming months,” according to Microsoft. PC makers began receiving the SP1 code in early February, but it will likely take at least a few months before new PCs based on that code hit the market. My guess is that Vista SP1 will be the default installation on new PCs by midyear.

Retail copies of Vista SP1. If you’d like to purchase a boxed copy of Vista SP1, those versions of the system will replace the initial Vista release on store shelves “in the coming months” as well. Again, this process should be completed by mid-year.

International users. The version of SP1 that was completed on February 4, 2008 included only the English, French, Spanish, German, and Japanese language versions of the update. The remaining languages that Microsoft supports will be released to manufacturing in April and ship worldwide after that, the software giant says.

Recommendations
There’s nothing like a final bit of silliness to cast yet another cloud of suspicion over a release that should have been a slam dunk for businesses that were waiting on SP1 to deploy Vista. That said, Microsoft says it won’t need to make any changes to the SP1 code to correct the device driver incompatibilities. Pedantic arguments over what constitutes “final” notwithstanding, SP1 is a high-quality release that does remove some important deployment blockers and improves Vista’s overall performance, reliability, and security. My advice here is simple: You should be installing SP1 as soon as possible. And if you haven’t yet deployed Vista, your excuses are running out. SP1 puts Vista over the top, despite the tiered release schedule.