Microsoft has taken the second release candidate (RC2) of its highly-anticipated Windows XP Service Pack 2 public to further clean up the code to meet a final release deadline this summer.

The Redmond, Wash., software giant, in the midst of a $300 million marketing blitz for the vaunted update, released the RC2 code Monday for developers to test.

While most service packs for Microsoft don't garner such attention, the company is throwing its weight behind a raft of security enhancements in the wake of years of buggy code and vulnerabilities in most of its applications. Windows XP SP2 Release Candidate (RC) 2 emphasizes security above all else.

RC2 boasts stronger default security settings and updates for Windows XP with new features and tools to help customers better defend their computers from hackers and viruses, according to a company fact sheet.

A new Windows Security Center allows users to check security functions on the Control Panel, which monitors information on firewalls, Automatic Update and third-party antivirus software.

These include improvements to Windows Firewall (formerly Internet Connection Firewall). With Windows XP SP2, Windows Firewall is enabled by default, which helps customers guard against attacks by unsolicited inbound traffic. The improved firewall also extends protection to a computer's boot time and shutdown process.

A new Attachment Manager guards users of Outlook Express, Windows Messenger and Internet Explorer by isolating potentially unsafe attachments during the opening process. Windows XP SP2 now installs code changes in IE that help protect against certain types of exploits. The software also limits hackers by restricting HTML in the local machine zone from running with elevated system privileges.

Many of the new features hinge on the company's Internet Explorer browser, including Internet Explorer Pop-up Blocker; Internet Explorer Information Bar; and Internet Explorer download monitoring. There is also better support for wireless radio protocol Bluetooth (define) and includes Windows XP Tablet PC Edition 2005, the next version of the Tablet PC OS.

Because of the sweeping changes, SP2 is considered by many software experts to be more of a full, new version of Windows with several fixes than it is a generic Microsoft service pack.

In fact, Jupiter Research analyst Joe Wilcox said the RC download betas are double the size of normal service pack upgrades from Microsoft. (Jupiter Research and this publication are owned by the same parent company.) Because of that, Wilcox, who recently heard a Microsoft XP product manager refer to SP2 as a service pack upgrade, scoffed at that notion that SP2 is anything less than a new OS.

''She said that they had to recompile part of the code,'' Wilcox said. ''My point is this: Is there a point where remodeling a house is so massive it should be called a new home? If the answer is yes, it's a new version. If the answer is no, then it's not. Either way, the changes are significant.''

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