Microsoft has finally broken its silence on the timing of the release of the highly anticipated Windows Vista Service Pack 1, saying the software updates should be in final release in the first quarter of next year with the company shipping off a beta next month to 10,000 to 15,000 testers.

The company stressed that SP1, "is not a delivery vehicle for new features," said David Zipkin, senior product manager for Microsoft. SP1 will include OS updates strictly to fix bugs and enhance the performance, reliability, and application compatibility of Vista, he said.

Zipkin acknowledged that Microsoft has "a reputation of sneaking fixes into service packs in the past." For example, Windows XP SP 2 included a host of new security features after XP was exploited by the Blaster worm and other serious attacks. However, the service pack also was incompatible with many applications running on XP, which caused massive headaches for a lot of users.

Vista SP1 will not break any applications already running on the OS. "Anything that works on Vista is going to keep on working on SP1," he said.

XP also will get another refresher in the next few weeks when Microsoft releases the third service pack for the soon-to-be outdated OS to customers and partners. Windows XP SP3 will be the last service pack update for XP and will include previously released updates as well as a small number of new fixes. It shouldn't dramatically alter the XP experience, according to Microsoft.

Vista SP1 will include the 20 updates for the OS already released over Microsoft's automatic update services as well as ones that are new to the update. In all, thousands of Vista files will be changed as part of the release, Zipkin said.

However, Vista SP1 will be a significantly smaller download than Windows XP SP2 was, he said. XP SP2 was more than 100MB in size, while Vista SP1 will be about 50MB, he said.

Microsoft will deliver SP1 over its automatic update services to consumers running Windows Vista. Business customers can use this service as well or roll out a stand-alone version of SP1, which has a bigger footprint, through whatever software a company uses for pushing updates to desktops, Zipkin said.

The stand-alone version of SP1 will be bigger than the one automatically pushed out through Windows update services for several reasons, one of which is it contains all of the 36 language updates, Zipkin said. The SP1 pushed out over the Web can detect what language a PC is running and only install that update.

Specifically, SP1 will fix performance features, such as allowing for the computer to resume functionality after being in the Hibernate or Standby state, and also reduce the time it takes between a user hitting CTRL/ALT/DELETE to get the log-in prompt so they can log on to Windows, Zipkin said.

Microsoft also in SP1 will improve the performance of Internet Explorer 7 to speed Javascript processing and reduce CPU utilization so sites running AJAX (Asynchronous Javascript and XML) can run faster, he said.

On the reliability side, the update will reduce the likelihood of Vista crashing from a vague "search protocol handler" error message that users have reported happens frequently, Zipkin said. The company also fixed other common crashes users have reported through Microsoft's automatic reporting service.

Many businesses have held off on updating to Vista until the arrival of SP1. Zipkin said that while Microsoft supports their decision, the company is recommending they test applications with Vista now so that they are ready to deploy immediately when SP1 is available. For consumers that may be waiting, Microsoft recommends they go ahead and install Vista or purchase a Vista machine now, and they will receive SP1 via automatic updates.

To date, Microsoft reports that about 60 million consumer licenses for Vista have been sold, and 42 million licenses have been sold to businesses through its volume licensing program.

Microsoft also pushed back the release date for Windows Server 2008, the next major update of its server OS, on Wednesday. The company now plans to release the OS to manufacturing in the first quarter of 2008; previously, the company was targeting the end of 2007. More information about Windows Server can be found on an internal company blog about the product.

This story was updated on August 29, 2007