Microsoft has released a first release candidate (RC1) of the first Windows Vista service pack (SP1), boosting the controversial operating system’s chances of becoming a mainstream desktop environment in 2008.

Subscribers to Microsoft Connect, TechNet and MSDN can download the code now and next week the program will be openly accessible from Microsoft’s Download Centre. By reaching RC1 status now, Microsoft is likely to have the full SP1 ready early next year, at which point many firms that are currently wavering could commit to large deployments of Vista.

On a blog posting, Microsoft product manager Nick White wrote that SP1 is designed “to address specific reliability and performance issues and also to support new types of hardware and several emerging standards. Further, SP1 is designed to make it easier for IT administrators to deploy and manage Windows Vista.”

Gartner analyst Annette Jump said, “If you look at mid-sized and large companies, less than five per cent have adopted Vista and many of those are part of early-adopter programmes from Microsoft. For historical reasons a lot of companies still think SP1 is important and traditionally firms have often waited a year after the OS release [to deploy]. The timing also links quite well with the time it takes ISVs to support the OS.”