Windows Code Name: “Longhorn.” The original idea about the operating system included the use of managed code in crucial parts of Windows, such as the Shell and Explorer. Both of these could be considered as the primary connection between the operating system and the user. This, and the fact that the currently used graphics subsystem was quite old and was lacking features that were commonly used in these days, led to the need of the creation of a new, better implementation which became known as Windows Presentation Foundation, and its code name “Avalon.” The fact that it relies directly on Direct3D and uses full hardware-acceleration, where available, to render graphical elements allows developers to create powerful scenes with multiple simultaneous animations, advanced effects and alpha blending. XAML, as in Extensible Application Markup Language, is the markup language created to simplify the UI design process.

Every operating system is characterized with its very own feature which is developed from early stages until final builds. Ever since the development of Windows Code Name: “Longhorn” started, Avalon was being developed simultaneously. What is known as “Aurora” became a characteristic of this new version of Windows. It is an effect and has two forms - a Desktop, and a “Preview Pane” one. The first one was designed to take advantage of the new developments, show off the power of XAML and Avalon as a whole, and the desktop’s ability to handle multiple animations without performance issues. On the other hand, what is known as ‘Preview Pane’ Aurora is an effect which resides in Windows Explorer’s Preview Pane module. Depending on the folder type browsed, it would change its color accordingly - for instance, red for Music, purple for Photos and Videos, and so forth.

The earliest known iteration of Aurora is found in certain Milestone 3 builds, as a still image. However, early conceptual art indicates an idea for a rather interactive experience during Log On.

Milestones 4 and 5 show that the development of Aurora has continued, too. A more complex yet simple DirectX scene was used to render an animation. This is one of the early attempts to implement rather powerful, moving wallpaper and have no performance issues at the same time. It is also the main source of the specific still image Aurora wallpapers of this ‘era,’ as well.

Ever since the development started, managed code has been used throughout the operating system - in many of its components, including the Shell which handles the Desktop, as well. The DirectX scene evolved into a fully Avalon-powered document which could be applied virtually anywhere in the operating system, including the desktop background. It featured multiple animations playing at the same time and because of the nature of the new graphics subsystem, there were no noticeable performance issues whatsoever. The fact that a major part of Windows Explorer was powered by Avalon let “Preview Pane” Aurora find its place in it. The latter was presented at Professional Developers Conference 2003, during the Aero keynote by Hillel Cooperman. Both of these, along with a working iteration of the Desktop Window Manager, were introduced in build 4074.idx02 released several months later, at Windows Hardware Engineering Conference 2004. However, neither of them were working by default and cannot be made to work natively in that particular build. In addition to that, the composition of Desktop Aurora was intentionally distorted and this required certain individuals, including myself, to work on fixing it.

According to its sources, the only publicly available iteration of Milestone 6 Desktop Aurora originates from build 4050.private/lab06_demo:

Windows Code Name “Longhorn”
For testing purposes only. Build 4050.private/lab06_demo.031013-1849
©, ™ Microsoft Corp. All rights reserved. User interface is ™ and trade dress of Microsoft Corp.

The very first public statement about either part of Aurora found in build 4074.idx02 was made by AeroXperience. The actual binaries were distributed later the same year by UX.Evolutions and AeroXperience providing the public with working packages demonstrating the two parts of Aurora.

Aurora is a key element of the AERO experience and could be seen in various places in Windows Vista such as the Log On screen, Preview Pane, WinSAT Assessments, screensavers and other.

Images are courtesy of Microsoft Corp. PDC 2003 photo is courtesy of Paul Thurrott.