"Comparing Vista to Windows XP SP2, with hard metrics, there is just no question that Vista is substantially more reliable," Allchin said.

On the security front, Vista is the first operating system to really go through the Microsoft secure development life-cycle, from the start, which means a number of rules and procedures to help ensure potential threats were addressed before the code even went into the product, he said.

"I have incredible confidence in the quality of this operating system because of the immense effort we have put into the engineering process, because of our automated tools, which scan for defects, and the time we spent on improving the underlying architecture, and the way in which we have addressed security. Customers will be safer when running Windows Vista," Allchin said.

While Windows XP SP2 was an advance in security and a release that Allchin said he was very proud of, there were things that Microsoft could not do with XP SP2, like the new defense against buffer overrun exploits called address space layout randomization, which is now in Vista.

Injecting a more personal note, Allchin said that his seven-year old son is running Vista on his machine, which is not running an anti-virus program as it is locked down with parental controls.

"I am feeling totally confident about that, which is quite a statement. I couldn't say that with Windows XP SP2. I also want to say that I am not advocating people not run anti-virus software, but my son's computer does not have it as it is extremely locked down and he is not using e-mail," he said.

What is the real compatibility picture for Windows Vista? Click here to read more.

Allchin also reconfirmed that he will be leaving the software giant at the end of January, at which time he will be replaced by Steve Sinofsky, who has headed the Office team until now, and who will then lead the Windows and Windows Live groups, with broad responsibility for planning future versions of Windows.

Allchin said he is "incredibly proud" of all the Windows team has achieved and hoped that it will be remembered for the progress made in terms of quality and security.

On the issues of hardware and application compatibility, Allchin said that Microsoft has worked with its partners throughout the development process and has tested thousands of applications internally.

What Is the Business Case for Upgrading to Vista? Click here to read more.

But now the ecosystem around the software is going to kick into high gear and complete the rest of the work around compatibility, he said, noting that they have about 10 weeks to do this.

"I can say, without any question, that when Windows Vista debuts in January, it will run more applications and hardware out-of-the-box than Windows XP or 2000 did when they debuted. This includes hundreds of the most used applications and tens of thousands of device drivers," Allchin said.

Microsoft also expects that business customers will jointly deploy Office 2007 system, Exchange 2007 and the enterprise version of Vista, which will give them "dramatic" improvements in security, manageability, reliability and productivity, he said.

This article was originally published on eWEEK.com.