查看“Windows 中的功能锁定”的源代码

Microsoft 曾多次使用各种机制在 [[Microsoft Windows 通述|Microsoft Windows]] 的预发布版本正式推出新功能之前将其隐藏起来。

== Windows 7 ==
The development of [[Windows 7]] marks the first time a deliberate centralized effort was introduced to conceal new features. Two separate mechanisms were introduced around [[Windows 7 build 6608|build 6608]]:
* '''Redpill''', a series of registry checks usually present within the executable that implements a hidden feature. Used to enable [[Taskbar#Superbar|Superbar]], desktop slideshow, [[Start menu]] pinning, jump lists, [[Internet Explorer 8]] enhancements, Aero Peek and Aero Shake.
* '''Bluepill''', which is implemented in the Application Compatibility Engine. It still results in a registry check, albeit indirect. Used to enable the new versions of [[Calculator]], [[Paint]], [[Sticky Notes]] and [[WordPad]].

[[Windows 7 build 7022|Build 7022]] is the last known build to include both Redpill and Bluepill.

== Windows 8 ==
A more elaborate feature lockout system, called Redpill or SuperPill, was introduced during the development of [[Windows 8]], which now takes advantage of the licensing subsystem as well as components that are not included with the base system. Noteworthy features hidden behind Redpill include the Start Screen, redesigned logon UI, new OOBE, Ribbon in Explorer, new Aero resources, and the pattern login (which later became the picture password login). However, while the majority of hidden features were locked using Redpill, simple registry checks remained the method of choice in some areas.

Product policies, a set of values usually used to determine what a particular edition can or cannot do, are now also used to control shell features. This made it considerably harder to overcome the protection, as the majority of licensing data is signed and handled largely at kernel level. The intended method of delivering the Redpill policies into an existing install (clean installs do not ship with them) was activating against the internal <code>win8act</code> server with the parameter <code>configextension=rpp</code>. Unlocking the functionality manually implies the need to sacrifice parts of licensing functionality. Besides product policy sourced values, a sizable chunk of behavior hidden by Redpill also depends on an external library called <code>shsxs.dll</code>, which is not included with the base Windows install and is only copied upon the activation of Redpill. This library is home to a large set of image and DirectUI markup assets, as well as a handful of functions used to initialize various parts of Metro such as Charms bar, Start screen search and the PC settings application.

Nearly all builds from Milestone 1 to shortly after the Developer Preview (currently [[Windows 8 build 7779|7779]] to [[Windows 8 build 8118|8118]]) have Redpill implemented. Exemptions are builds from the <code>fbl_eeap</code> and <code>winmain_win8m3_eeap</code> branches, e.g. [[Windows 8 build 8064|build 8064]], which do not have any form of Redpill implemented as all traces of Metro user interface components were removed from the operating system at compile time. These builds were released to [[w:Microsoft|Microsoft]] partners via the Ecosystem Engineering Access Program (EEAP). The only available build with Redpill unlocked out of the box is [[Windows 8 build 8102|build 8102]], the original Developer Preview. Due to the complexity of the mechanism, a formerly widespread method of unlocking Redpill on other builds was to use a modified set of components from build 8102, although the reliability of this method decreased with earlier builds. It wasn't until the introduction of [[Redlock]] with a custom version of <code>shsxs.dll</code> reimplemented from scratch that Redpill could be unlocked for builds before [[Windows 8 build 7927|build 7927]].

=== Unlockers ===
Several tools have been developed to enable features hidden by Redpill:
* '''[[RedPill Enabler]]''' (also known as the '''MDL Redpill Enabler''', named after the forum where it was first published on) was the one of the first public applications meant to enable features restricted by Redpill. It was developed by Vizion, a member of the My Digital Life forum, and was first released on 17 June 2011.
* '''[[Metro Unlocker]]''' was developed by MetroFetro, a YouTuber and developer. It was the first public application that allowed for all restricted features to be enabled, including the Start screen, and remained the only application capable of performing such a task from its initial release in 2016 until the release of Redlock in 2020.
* '''[[Redlock]]''' was developed by lucasm and gus33000, two BetaWiki members and software developers. The initial version was released on 29 January 2020. The tool is designed to replicate Microsoft's original Redpill implementation as closely as possible.

== Windows 10 and later ==
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Windows versions since the [[Windows 10 Anniversary Update]] utilize a simplified feature locking mechanism which make use of numeric strings internally referred to as Velocity staging keys. These values are controlled by dynamic link library <code>fcon.dll</code> (''Feature Configuration'') found within the <code>Windows\System32</code> directory, responsible for managing feature enablements in the <code>HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FeatureManagement</code> key (and related subkeys, such as <code>Overrides</code> and <code>EnterpriseTempControls</code>). Features can also be restored from their previous state through the use of a Last Known Good store (found in <code>HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FeatureManagement\LastKnownGood</code>) if the library detects problems with the existing overrides. Built-in feature overrides were introduced from as early as [[Windows 11 build 22606]].

The availability of certain features may depend on the current state of an associated staging key. In most cases, feature states can be modified if the priority data returns 8 (<code>User</code>). In certain cases, a feature may be either forcibly enabled or disabled in code if its priority returns <code>ImageDefault</code>. This type of feature lockout also introduces a data type called "variants", which ship multiple treatments for the same staging key. Treatments may vary between devices and installations.

Currently, most features introduced in newer Windows releases employ this method for concealing and/or testing features that are not ready for widespread release to a scoped set of users. The first known feature to use this new feature lockout mechanism is Sets, which was first introduced in [[Windows 10 build 17618]] with staging keys <code>13849566</code> and <code>10727725</code>. Traditional feature enablement checks via the Windows registry remain as a perennial choice for certain aspects of the operating system.

=== Tools ===
There are four available tools that offer the ability to manage the states of Velocity staging keys:

* [https://github.com/thebookisclosed/ViVe/releases '''ViVeTool'''] - Developed by Albacore, recommended for enabling features in later builds of Windows 10 and 11.
* [https://github.com/riverar/mach2 '''mach2'''] - Developed by Rafael Rivera, used to enable features from older Windows 10 builds like [[Windows 10 build 17618|build 17618]]'s Sets and [[Windows 10 build 18946|18946]]'s new start menu. Discontinued since December 2020.
* "'''Experimental features'''" drop-down menu in [[Settings]] (Windows Update > Windows Insider Program); Velocity staging key <code>40062046</code> - Included as part of internal Windows builds (e.g.: [[Windows 11 build 25267 (rs_wdatp_edr)|build 25267 (rs_wdatp_edr)]]). It is one of two official methods used internally by Microsoft employees to enable various staging keys, such as security fixes from the Microsoft Security Response Center (MSRC), non-public shell features and bugfixes or improvements for internal Windows functionalities (such as the DirectX graphics stack). It may not list features that are currently unfinished.
*'''Staging Tool''' (<code>StagingTool.exe</code>, version <code>10.0.25910.1000</code>): This is another official internal tool used by Microsoft employees to manage and configure the states of Velocity staging keys through the use of a command line-based user experience, unintentionally distributed in two internal Feedback Hub quests that were made public on 2 August 2023. The link was later taken down, although archived versions of the tool exist online.

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== Gallery ==
<gallery>
Windows11-10.0.25267.1001-Settings-ExperimentalFeatures.png|[[Windows Insider Program]] page with Experimental Features dropdown enabled, in [[Windows 11 build 25267 (rs_wdatp_edr)]]
</gallery>

[[Category:Microsoft Windows]]