If you’re interested in the history of Windows, you probably know a bit 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 was supposed to include a filesystem to replace NTFS, something we still haven’t gotten almost two decades later.
One of Vista’s most noticeable and memorable additions was the “Aero” design, which used Direct3D to draw translucent, glassy windows that could fade gracefully in and out of view, replacing the 2D windows from older Windows versions. Over the weekend, Twitter user @thebookisclosed (who makes a habit of digging deep into old development versions of Windows) gave us a look at the earliest known version of Aero in a Longhorn development build from March of 2003, nearly four years before Vista would be released to the public.
This early Aero effect looks pretty different from what we eventually got in Windows Vista—the translucency and the smoked-glass look are here, but the final effect as seen in Windows Vista and Windows 7 is shinier, and the blur is more pronounced. (In the Longhorn version of the effect, the reduced blur could create readability issues if, for example, the text in the title bar and text in an underlying window were to run together.)
Though the Aero effect and the proto-Sidebar will both be recognizable to Vista users, these 2003-era Longhorn builds bear little similarity to the OS that Microsoft would finally release to a lukewarm reception in early 2007. Wary of feature creep and instability, Microsoft “reset” Longhorn’s development in 2004, tossing out these early builds and starting over again from Windows Server 2003’s codebase. Many of the security features that had been planned for Longhorn, including a beefed-up Windows Firewall, were backported to Windows XP in the form of Service Pack 2, and the time and effort spent on XP SP2 further delayed Longhorn’s release.