Windows Vista

Windows Vista (codenamed Longhorn) is an operating system by Microsoft, released to manufacturing on 8 November 2006 and general availability on 30 January 2007. It is the seventh operating system in the Windows NT operating system line, succeeding Windows XP and preceding Windows 7. It also had one of the longest development periods in Microsoft's history starting in May 2001 and continuing until November 2006.

Development
The "Longhorn" project started in earnest in May 2001, originally intended as a bridging release between Whistler and the later version of Windows codenamed Blackcomb. As development progressed, many features slated for Blackcomb became part of Longhorn, and employees jumped ship from other parts of the company. As development progressed before the reset, Longhorn became a heavily bloated and unstable piece of vaporware, with release dates being pushed back on several occasions. The first build to leak publicly was build 3683, which contained a new theme and also the foundations for Windows Future Storage (aka WinFS) and Avalon (the codename for the Windows Presentation Foundation (WPF) framework) - the development of which began on or before April 2001 based on dates in the WPF components of the .NET 4.5.1 Reference Source.

Stability increasingly became an issue as development progressed, and very few builds were publicly released as a result. Only two builds were distributed at conferences and to developers: build 4051 and build 4074. The last known confirmed build from before the development reset is build 4093. At 16:29 on 19 August 2004, (the same day as the compilation of 4093), Microsoft reset the development of Windows Longhorn and started fresh using Windows Server 2003 Service Pack 1 as a codebase, starting the Omega-13 period. Immediate post-reset builds were primarily focused on reintegrating features from the pre-reset builds while maintaining stability. Most of these builds are similar to Windows XP in the overall look and feel. Few builds from this stage of development have been released, officially or otherwise. Development of Longhorn continued, albeit many features originally slated for inclusion were delayed or dropped to produce a more realistic set of goals for the OS. Examples of said features include WinFS and "Castle" (later shipped in Windows 7 as HomeGroup).

In April 2005, a pre-beta build was released to testers (build 5048) on WinHEC 2005. This build showed the progress made since the reset and also proved much more stable than previous builds. Build 5112 (Beta 1) was released to the public soon afterward in July and showcased an early version of the Aero interface, as well as many stability improvements over XP. Later that year and the next year, many builds were released to testers in a public beta program, with builds dubbed as "Community Technology Previews" (CTPs). The final build that was pushed out to public preview testers was Release Candidate 2 (build 5744). Build 5824 was supposed to be the RTM version but since it had an upgrade bug that would stop the OOBE from working after the "Thank You" screen. The RTM build was build 6000.16386, compiled on 8 November 2006. Windows Vista reached General Availability on 30 January 2007.

User interface
The new Aero user interface has been introduced, which included large design changes to many of the built-in apps. Microsoft also encouraged third party developers to make their applications consistent with Aero, with the company for the first time producing a definite set of design guidelines that included advice ranging from graphics design to message text wording.

An important aspect of the user interface was the hardware accelerated Windows Aero theme. This was made possible by the new Desktop Window Manager, a compositing window manager that worked hand in hand with the also new Windows Display Driver Model (WDDM). The compositing nature of DWM allows for eye candy such as Aero Glass or Flip 3D, but also prevents various rendering glitches that were common for previous versions of Windows. The exact appearance of Aero Glass can be further customized by toggling the transparency or changing the frame's color, which is not possible for themes that are not composited. Live taskbar thumbnails have also been introduced, it shows a preview of the app window when hovered over its button in the taskbar.

Certain parts of the Windows shell have been updated to use glass transparency as well such as taskbar, Start menu, setup interface and window borders.

The Home Basic edition of Windows Vista utilizes a variant of Aero called Vista Standard, which still relies on DWM however doesn't include glass transparency, window animations and other visual effects Aero provides such as Flip 3D and live taskbar thumbnails.

For systems that relied on older drivers made for Windows XP, Vista also included the Windows Basic style, which used the older XP-style theme engine. It's the default theme in the Starter edition.

Most of the icons have been updated to use a more visually realistic style and they can now be scaled at more sizes (however it's required to have 16x16, 32x32 and 256x256 sizes).

Editions
Windows Vista came in many editions. Unlike Windows XP, there was no special edition for Media Center, 64-bit capability and Tablet PCs since these features were included in at least one of the consumer editions. Windows Vista also did not have an embedded version, perhaps due to the considerable grunt required to run optimally.


 * Starter: This edition is intended for emerging markets and low-cost PCs. As in XP, the three-program limit was there, and only 1GB RAM was accepted. Other software restrictions applied as well. This version is hence not available in 64-bit. This edition is the only edition of Vista that doesn't include Desktop Window Manager and Windows HotStart. Only Windows XP Starter can upgrade to Windows Vista Starter.
 * Home Basic: Found in low cost to mid-end, this version of Windows Vista does not fully have Aero (though it has DWM) and hence does not have effects like transparency and 3D Flip. Windows Media Center, Windows DVD Maker and various backup features are also not present in this edition. Parental Controls are included, however. Unlike the Starter edition, it does not have the hardware and 3-program limit. A sub-edition called "Home Basic N" existed for the European Market which didn't include Media Player due to EU's sanctions against Microsoft's anti-trust law violation.
 * Home Premium: The consumer version of Windows Vista, this version includes full Aero functionality, Windows Media Center, Premium Games (eg - InkBall and Purble Place) and various WMP11 audio decoders. However, it lacks BitLocker and Complete PC Backup.
 * Business: The business-oriented version of Windows Vista, it contains several features like full RDP (client/host) capability, Group Policy, domain joinability and Windows Fax and Scan. However, Windows Media Center and Parental Controls are not included, and Premium Games are disabled by default. For the embedded market, there's a sub-edition called "Windows Vista Business for Embedded Systems". A sub-edition called "Business N" existed for the European Market which didn't include Media Player and Movie Maker due to EU's sanctions against Microsoft's anti-trust law violation.
 * Enterprise: The business variant of Windows Vista. It is similar to Ultimate, but without consumer-specific features such as Windows Media Center and Parental Controls. Rather, it includes enterprise-specific tools, Windows Fax and Scan and Windows Services for UNIX. This edition is only available to customers who participated in the Microsoft Software Assurance program.
 * Ultimate: The top consumer variant of Windows Vista, it is a merger of the features included Windows Vista Home Premium and Business. BitLocker is included in this version. This edition also allows the user to install "Windows Ultimate Extras", several Ultimate SKU addons that include games, sound schemes, Windows Dreamscene, BitLocker and Marketplace enhancements. For the embedded market, there's a sub-edition called "Windows Vista Ultimate for Embedded Systems". Another sub-edition of Vista Ultimate called "Windows Vista Product Red" was related to the "Product Red" campaign to support the global funding for ADIS, Tuberculose and Malaria diseases. This sub-edition of Vista included extra Product Red wallpapers, gadgets and a desktop theme.

Sound scheme
No build of Windows Vista (including pre-reset) used or even included the widespread sound scheme that appears in several fanmade Longhorn or Vista themes, which was actually a sound scheme titled "Deep Fantasy", commercially available on NEO Sounds, a stock sound/music website in the 2000s. The Windows XP sounds remain and are used in all pre-reset builds, with a few being swapped with Vista sounds between builds 5469 and 5840.16384.

The alleged Windows Vista Beta 1 startup is actually  used in the Speech Recognition tutorial in build 5308.6 and onwards. Likewise, the alleged Windows Vista Beta 2 startup is actually a jingle used in Vista Beta 2 Help video outros.

Milestone 2
These builds are also referred to as Alpha builds.

Development reset
These builds are also referred to as Omega-13 builds.