You've waited and waited, and the day finally arrived: Last Friday afternoon, Microsoft began sending out invitations to private beta testers for Longhorn, the next major version of Windows. According to the invitation, the Longhorn beta includes client and server versions as well as related development tools for programmers who elect to participate. Additionally, testers can optionally beta test Microsoft Internet Explorer (IE) 7.0 for Windows Server 2003 and Windows XP.
  
"The next version of Windows, code-name Longhorn, promises to be the most secure and intuitive Windows release to date," the invite reads. "It delivers on the promise of allowing people to use their computers more effectively and confidently to achieve their goals and pursue their passions. It offers new tools to help protect the integrity of your system and your information, easier ways to find, visualize and organize your information, and provides better integration across applications, devices and systems."
  
The invite also includes the following vague information about the focus of Longhorn Beta 1:

   - A strong focus on the fundamentals of the OS, including advancements in reliability, performance, deployment, and ease of use.
   - Major improvements to help PC users work smarter and to provide exciting new experiences for home users.
   - The next-generation developer platform to make it easier for developers to create breakthrough applications.

   Microsoft will notify beta testers "this summer" when the beta 1 release is ready for testing. My sources have pegged the first Longhorn beta as happening in late July. 
  
There has been some discussion about the Longhorn Beta 1 build number in the public Longhorn newsgroups. Mike Brannigan, a consultant working with Microsoft, disclosed this week that the company forked the Longhorn code base recently to hit the beta 1 milestone. This is standard procedure, but it's interesting that a Microsoft representative decided to discuss this publicly. 
  
"We are now currently developing two parallel build branches, the 509x \[builds\] upwards to 51xx and the 52xx \[builds, which are post-Beta 1\]," Brannigan wrote. "What we do when we get close to a milestone build such as Beta 1 is we fork the development tree. This allows us to focus one team on finishing off the Beta 1 code--\[for\] bug hunting, etc. but not \[for\] adding any additional features to it--while we continue to develop towards Beta 2 on the other branch, taking the bug fixes coming from the Beta 1 branch and continuing to add features, etc. as we build to Beta 2. This allows for the most efficient way to get a stable Beta 1 \[build\] and not hold up the complete development cycle."