- For post-reset history and builds, see Windows Vista.
|Kernel version||NT 6.0|
|CPU architecture||x86, x64, IA-64|
|Preceded by||Windows XP|
|Succeeded by||Windows Vista|
Longhorn was the codename for the planned successor of Windows XP.
One of the original - and largest - changes is that, with "Longhorn", the .NET Framework would be integrated into the core Windows platform, deprecating the traditional Win32 API. During development, portions of the operating system were rewritten, causing memory leaks and instability, particularly in Windows Explorer.
Development was reset, but post-reset builds continued to use the "Longhorn" codename until the final name, Windows Vista, was announced on 22 July 2005.
"Longhorn" was chosen as the codename for the operating system to represent its initial status as an internim release between Windows XP (codenamed "Whistler") and "Blackcomb". Whistler and Blackcomb are names of mountains in British Columbia, Canada, and Longhorn is the name of a saloon located in between the two mountains, representing the operating system's initial status as an internim release between the two products. Bill Gates would later state that this choice for a codename of the operating system was "a bit random".
The popular belief is that pre-reset "Longhorn" builds are based on Windows XP. This was likely spurred by Paul Thurrott's statement on his review of build 5048: "The problem, I was told recently, was that the underpinnings of Longhorn--then based on the Windows XP code base--were struggling under the weight of all of the technologies that Microsoft planed to implement in this release." However, pre-reset "Longhorn" builds are based, not on XP, but on Windows Server 2003 release candidate code. The xpclient release branch, dedicated to XP, spun off from the main branch in 2001. The main branch continued to compile Server 2003 builds at the 3xxx range, such as build 3663 (release candidate 1), until the dnsrv branch dedicated to Server 2003 spun off from the main branch in 2002. After that, the main branch began compiling Longhorn builds.
Several different logos were created throughout the development of "Longhorn". Early builds used 2D and 3D representations of a longhorn bull; later builds included white or glass versions of the Windows flag.
Concepts, presentations, demos and prototypes
- Earliest concepts (2002, 2003)
- MSX "Longhorn Days" (2003)
- Amazon.com demo (PDC 2003)
- Get Users to Fall in Love With Your Software - Hillel Cooperman's demo from PDC 2003 (video)
- Business solutions enabled by Longhorn technologies by Carter Maslan (2004, mockups only)
Implementation of concepts
- For server builds, see the Windows Server 2008 page.
Planning stage. No builds known.
- WinHEC 2004 Aero demo build
- See Windows Vista.
- Athens PC
- WinHEC 2003
- PDC 2003
- WinHEC 2004
- Windows Sidebar
- Desktop Composition Engine (Longhorn)
- Desktop Window Manager
- Friendly Fire
- Self-Host Vote
- Next-Generation Secure Computing Base
- Whistler Vacation Tips. "Windows Blackcomb: See Why Bill Gates Loves Whistler"
- Thurrott, Paul. "Windows 'Longhorn' FAQ"
- Thurrott, Paul. "Road to Gold: The Long Road to Windows Vista Part 1: 2001-2001"
- Levy, Steven. (November 23, 2003). "He's Still Having Fun"
- Thurrott, Paul (5 May 2005). Windows Longhorn Build 5048 Review. Archived from the original on 6 May 2005. Retrieved on 2 April 2022.
- The very beginning. Retrieved on 2 April 2021.
- Lucas Brooks (@mswin_bat) (14 February 2022). Microsoft actually implemented a lot of the crazy stuff seen in their Longhorn concepts. The private Aero theme was all that's needed to get this lovely striped taskbar/sidebar in M5. Picture on the right shows the M5 port of the M7 Aero theme.. Twitter. Retrieved on 16 April 2022.
- Grabberslasher (9 June 2008). Longhorn Labs. Si vis pacem, para bellum. Retrieved on 18 April 2022.
- The Longhorn Kernel-Mode Timebomb
- Aborted Longhorn concepts/features
- Windows "Longhorn" features present in Windows Vista
- ReflectiaX's Longhorn Beta and Demo Files Thread!
- The Pillars of Longhorn
- The Pillars of Longhorn: Living La Vida Longhorn (Longhorn Foghorn)
- Introducing Indigo: An Early Look, February 2005 (May 2005 version from the authors' site)
- Longhorn Developer Center Home: User Experience (Aero)
- A First Look at Writing and Deploying Apps in the Next Generation of Windows
- Jim Allchin - The Longhorn Update
- Paul Thurrott's SuperSite for Windows: The Road to Windows "Longhorn" (last updated 13 November 2002)
- Aurora & Aero | Microsoft Longhorn
- Hacking Avalon – 1: Disable it
- Hacking Avalon – 2: Port it | Microsoft Longhorn
- Hacking Avalon – 3: Compiling xaml
- Managed C++ and the Longhorn Shell
- .NET framework
- Help center
- UX.Unleaked Grabberslasher's blog that describes several unleaked "Longhorn" builds
- Jim Allchin’s Mac message: The full text (leading up to the reset)
- Longhorn Rumors: What's true and what isn't — WinWorld
- Document Preview : General Windows Support
- Retro: Windows Longhorn - Nerdshack
- Code name: Longhorn by John Clyman, PC Mag article
- Microsoft Shows New Features of Windows Longhorn (PCWorld article from 5 May 2004 about WinHEC 2004)
- Indigo: The Longhorn Communications Layer (Figure 1)