As previouslyby CNET News.com, Microsoft had been expected to complete work on the update by the end of the week. The free update will be available to the public for download on Sept. 9.
The software giant periodically issues free updates, known as service packs, in order to fix bugs or revamp security software. In addition to various fixes, Windows XP Service Pack 1 offers features to support upcoming hardware:and the .
The changes supporting Windows Media Center PCs and the Tablet PC will be available only to PC manufacturers. Hewlett-Packard and some other computer makers are prepping Windows Media PCs for holiday release. These systems will include a second user interface for accessing Windows XP's digital media features via a remote control.
The Tablet PC, slated for Nov. 7 release, is a notebook hybrid that allows people to input text by writing on the display with a stylus. Microsoft sees big potential for the devices among businesses and schools. Microsoft Research, for example, has produced a short film demonstrating the benefits of the Tablet PC for in-classroom and remote-access teaching.
Official release of the service pack means computer manufacturers can begin final testing of new Windows Media Center PC and Tablet PC products for November. Additional testing is expected before computer makers begin shipping Windows XP with Service Pack 1 on new PCs.
The first computers with the updated Windows XP are expected to be available in early October, said sources close to several PC manufacturers.
NPDTechworld analyst Stephen Baker said Microsoft's release schedule works well.
"For PC sales, the timing is good," Baker said. "Remember, Windows XP came out about the same time last year, and that was good timing too. That's a smooth period for PC makers to incorporate a new service pack into PC configurations."
Consumers or businesses can apply the service to Windows XP Home Edition, Windows XP Professional or Windows XP 64-bit Edition.Behind the scenes
Most of the changes introduced in the service pack will be invisible to computer users. The update incorporates numerous bug patches and security fixes already released by Microsoft. People can also retrieve these fixes manually or via Windows XP's feature.
Service Pack 1 also consolidates previously released OS updates and adds some new ones, such as USB 2.0 device drivers and the .Net Framework, which is essential for Windows XP to support Microsoft's .Net Web services strategy. The service pack also introduces a new version of , Microsoft's instant messaging client.
Some software pirates could be in for a surprise. Microsoft is using the operating system'sfeature to clamp down on the majority of Windows XP piracy. The feature locks software to the hardware; this design allegedly cuts down on piracy. Product IDs stolen through Microsoft's volume licensing program accounts for about 90 percent of the Windows XP piracy, according to Microsoft. The Service Pack won't install on the Windows XP copies using a stolen number.
Microsoft made a similar move with itsAntitrust tweaks Service Pack 2, which the company last week. The update will not install on some pirated copies of the software suite. Microsoft estimates that about half of the 300 million copies of Office in use are pirated.
The Windows XP update is unique because it a new control for setting default middleware--such as Web browser and media player software--as required by Microsoft's pending antitrust with the Justice Department and nine of the 18 states that sued the company.
Consumers may find that the new middleware control has little effect on middleware already installed on their PCs, however. Developers of software programs for Windows XP must "register" middleware with the updated OS to use the new middleware control, according to Microsoft. And software makers, such as America Online, say that the only way to do that is either to update existing software or wait for their new releases.
AOL's current software will not work with the new middleware control, company spokesman Andrew Weinstein said. That's largely because "the software code (from Microsoft) was not made available to any software developer until a couple of months ago," he said. Other than that, he added, existing versions of AOL's software will work with Windows XP and Service Pack 1.
Weinstein said consumers will have to wait for future releases of the company's software to use the middleware control. AOL Time Warner is currently testingand , both of which are expected to support the new middleware feature.
People who use the Opera browser also may have to wait for an update to that program to support the new middleware control.
"We have to do some work," Opera CEO Jon S. von Tetzchner said. "If we need to register (in Windows XP in) a new way, we will find out how to do that. Microsoft does not have a tendency to contact us and tell us how to do things."
RealNetworks said an upcoming version of its RealOne media player will register with the middleware control, but existing versions will not.
MusicMatch, which makes programs for creating and organizing digital music, said version 7.2 of its software will work with the new middleware control. The software is available from the company's Web site. MusicMatch estimates that about 25 percent of its customers use Windows XP.
The new middleware control lets PC makers or consumers hide--but not remove--access to five Microsoft middleware programs: Internet Explorer,, Windows Messenger, Outlook Express and Microsoft's version of the Java Virtual machine. The new control also lets PC makers and consumers set the defaults for middleware programs, whether they are from Microsoft or from third parties.
Consumers upgrading Windows XP with the service pack will find the new control as the fourth option of "Add or Remove Programs," which is located in the operating system's control panel. The three choices--"Microsoft Windows," "Non-Microsoft" and "Custom"--allow a person to instantly reset all the middleware defaults. The "Microsoft Windows" option sets the software giant's own middleware as the default. "Non-Microsoft" lets a person switch to middleware from other companies. "Custom" is used to mix and match Microsoft and non-Microsoft middleware as the default programs.
New PCs will contain a fourth option, "Computer Manufacturer Configuration," which restores the middleware settings to the defaults that come on the system. For example, Dell Computer and Gateway ship MusicMatch on their PCs, which could be set as the default using the new control. Neither company would discuss its plans ahead of Microsoft release of the service pack.
Microsoft earlier APIs) contained within Windows XP. That disclosure was necessary before the software maker could release the Windows XP update, according to the terms of a proposed settlement of the company's antitrust case, which a federal judge still must approve.technical information known as application programming interfaces (