If you’re interested in the history of Windows, you probably know something about “Longhorn”, Microsoft’s internal codename for the OS update that would eventually become Windows Vista. Microsoft planned a huge list of new features for Longhorn (and its planned successor, codenamed Blackcomb), many of which never saw the light of day. Longhorn would include a file system to replace NTFS, something we still almost two decades later still not received.
One of Vista’s most notable and memorable additions was the “Aero” design, which Direct3D used to draw translucent, glass-like windows that could gracefully disappear in and out of sight, replacing the 2D windows of older Windows versions. During the weekend, Twitter user @thebookisclosed (who makes a habit of digging deep into old development versions of Windows) gave us a glimpse into the earliest known version of Aero in a March 2003 development by Longhorn, nearly four years before Vista was due to be released to the public.
This early Aero effect looks quite different from what we ended up getting in Windows Vista – the translucency and smoked glass look are here, but the final effect as seen in Windows Vista and Windows 7 is glossier and the blur is more pronounced . (In the Longhorn version of the effect, the reduced blurring could lead to readability issues if, for example, the text in the title bar and the text in a sub-window were to overlap.)
While the Aero effect and the proto sidebar will both be recognizable to Vista users, these 2003-era Longhorn builds bear little resemblance to the operating system Microsoft would eventually release lukewarm in early 2007. “reset” Longhorn’s development in 2004, ditching these early builds and starting over from the Windows Server 2003 codebase. Many of the security features planned for Longhorn, including an improved Windows Firewall, were rolled back to Windows XP in the form of Service Pack 2, and the time and effort spent on XP SP2, further delayed the release of Longhorn.