Windows 8.1

Windows 8.1 is a personal computer operating system, a member of Windows NT family and an immediate successor to Windows 8. First unveiled and released as a public beta in June 2013, 8.1 was released to manufacturing on August 27, 2013, and hit general availability on October 17, 2013. While marketed as a free update for 8 and Windows RT available via Windows Store for existing users, it is only available freely for Windows 8 licenses obtained through retail or OEM channels; all other users must obtain 8.1 through their respective subscription or enterprise channels. However, as with previous service packs, installation of 8.1 will be required to maintain access to Windows 8's mainstream support after October 17, 2015, per Microsoft's software lifecycle policies.

Released as part of a shift by Microsoft towards regular, yearly updates for its platforms and services, Windows 8.1 was primarily intended to address complaints which Windows 8 faced from users and reviewers on launch. Visible enhancements includes an upgraded Start screen, additional snap views, additional bundled apps, tighter SkyDrive integration, a Bing-powered unified search system, restoration of a visible Start button on the taskbar to open the Start screen, and the ability to restore the previous behavior of opening the user's desktop on login instead of the Start screen. Windows 8.1 also added support for emerging technologies such as high resolution displays, 3D printing, Wi-Fi Direct, and Miracast streaming.

Windows 8.1 received relatively positive reception, with critics praising the expanded functionality available to apps in comparison to 8, its SkyDrive integration, along with its user interface tweaks and the addition of expanded tutorials for operating the Windows 8 interface. Despite improvements to user experience, Windows 8.1 was criticized for not addressing all Windows 8 problems.

History
In February 2013, ZDNet writer Mary Jo Foley published an article containing information from a "very accurate tipster" about "Blue", the codename for a wave of planned updates across several Microsoft products and services, including Windows 8, Windows Phone 8, Outlook.com, and SkyDrive. In particular, the report detailed that Microsoft was planning to shift to a more "continuous" development model, which would see updates for its major platforms released on a consistent yearly cycle to keep up with market demands. Lending credibility to the reports, Foley noted that a Microsoft staff member had listed experience with "Windows Blue" on his LinkedIn profile, and listed it as a separate operating system from 8.

A post-RTM build of Windows 8, build 9364, leaked in March 2013. The build, which was believed to be of "Windows Blue", revealed a number of enhancements across Windows 8's interface, including additional size options for tiles, expanded color options on the Start screen, the expansion of PC Settings to include more options that were previously exclusive to the desktop Control Panel, the ability for apps to snap to half of the screen, the ability to take screenshots from the Share charm, additional stock apps, increased SkyDrive integration (such as automatic device backups), Internet Explorer 11, and other new options. Shortly afterward on March 26, 2013, corporate vice president of corporate communications Frank X. Shaw officially acknowledged the "Blue" project, stating that continuous development would be "the new normal" at Microsoft, and that "our product groups are also taking a unified planning approach so people get what they want—all of their devices, apps and services working together wherever they are and for whatever they are doing."

On May 14, Microsoft officially announced that the "Blue" update would be named Windows 8.1. Following a keynote presentation focusing on the update, the public beta of Windows 8.1 was released on June 26, 2013 during Build Conference. Build 9600 of Windows 8.1 was released to OEM hardware partners on August 27, 2013, and became generally available on October 17, 2013. Unlike past releases of Windows and its service packs, volume license customers and subscribers to MSDN Plus and TechNet Plus were initially unable to obtain the RTM version upon its release; a spokesperson stated that the change in policy was to allow Microsoft to work with OEMs "to ensure a quality experience at general availability." However, after criticism, Microsoft reversed its decision and released the RTM build on MSDN and TechNet on September 9, 2013. Prior to the release of 8.1, Microsoft premiered a new television commercial in late-September 2013 that focused on its changes as part of the "Windows Everywhere" campaign.

Distribution
Unlike updates of a similar nature for previous versions, Microsoft did not refer to 8.1 as a "service pack" for Windows 8, branding it as a point release of 8 and marketing it as an "update" for the operating system. However, it is still a service pack for the purposes of Microsoft's support lifecycle policy; as was the case on previous versions of Windows, 8.1 is considered to be part of Windows 8's support lifecycle, and upgrading to 8.1 will be required to maintain access to mainstream support and updates after October 17, 2015—two years after its release.

Windows 8.1 is primarily available as a free download through Windows Store for users of retail or OEM copies of Windows 8, Windows 8 Pro, and Windows RT. The Windows Store version of the update must be downloaded individually on each device, and is not readily available to consumers as a standalone installer or ISO image, unlike the service pack updates used by previous versions of Windows (which were distributed as standalone installers and via Windows Update). Although users discovered a workaround to download an ISO of 8.1 using a Windows 8 product key and the respective online setup programs of 8 and 8.1, the installer only accepts Windows 8.1-specific product keys (however, the product key can still be changed following installation). Users of Windows 8 Enterprise, volume license customers, and TechNet or MSDN subscribers must manually download standalone installation media for 8.1, installed through the traditional Windows setup process as an in-place upgrade or clean install (which too requires an 8.1-specific product key).

New retail copies of Windows 8 were also released alongside the update. Unlike previous retail copies of Windows 8 (which only supported upgrade installations), all retail copies of Windows 8.1 are "Full" versions that can be installed on any computer, even if it does not have an existing operating system. Despite this change, pricing for retail copies of 8.1 remain identical to that of 8. Microsoft stated that the change was in response to customer feedback, and to allow more flexibility for users.

Due to changes to improve its "security effectiveness", the 64-bit version of Windows 8.1 no longer supports processors which do not implement the double-width compare and exchange (CMPXCHG16B) CPU instruction (which the installer reports as a lack of support for "CompareExchange128"). A Microsoft spokesperson noted that the change primarily affects systems with older AMD 64-bit processors, and that "the number of affected processors are extremely small, since this instruction has been supported for greater than 10 years." Even if the system does have an otherwise compatible processor, the motherboard must also support the instruction—which can also cause the problem to occur on Intel processors in select cases. These changes do not affect the 32-bit version of Windows 8.1.

New and changed features
Many of the changes on Windows 8.1, particularly to the user interface, were made in response to criticisms from early adopters and other critics after the release of Windows 8.

User interface and desktop
The Start screen received several enhancements on 8.1, including an extended "All Apps" view with sort modes (accessed by clicking a new down arrow button or swiping upward), small and extra-large sizes for tiles, and colored tiles for desktop program shortcuts. Additional customization options were also added, such as expanded color options, new backgrounds (some of which incorporating animated elements), and the ability for the Start screen to use the desktop background instead. Applications are no longer added to the Start screen automatically when installed, and all desktop applications pinned to the Start screen have colored tiles. The app snapping system has also been extended; up to 4 apps can be snapped onto a single display depending on screen size, apps can be snapped to fill half the screen, and can also be used on any display in a multi-monitor configuration. Apps can also launch other apps in a snapped view to display content; for example, the Mail app can open a photo attachment in a picture viewer snapped to another half of the screen. Improved support is also provided by apps for using devices in a portrait (vertical) orientation. The lock screen offers the ability to use a photo slideshow as its backdrop, and a shortcut to the Camera app by swiping up. The on-screen keyboard has an improved autocomplete mechanism which displays multiple word suggestions, and allows users to select from them by sliding on the spacebar. The autocomplete dictionary is also automatically updated using data from Bing, allowing it to recognize and suggest words relating to current trends and events.

To improve the usability of the desktop interface, a visible Start button was restored to the taskbar for opening the Start screen, and the Quick Links menu (accessed by right-clicking the Start button or pressing Win) contains shutdown and sign-out options. "Taskbar and Navigation properties" [sic] dialog box can modify certain interface behaviors, such as disabling the upper hot corners for using the charms and recent apps list, going to the desktop instead of the Start screen on login or after closing all apps on a screen, automatically opening the "All Apps" view on the Start screen when opened, and prioritizing desktop programs on the "Category" sort mode on "All Apps". To assist users in learning the Windows 8 user interface, an interactive tutorial is also offered, along with a new Help + Tips app for additional information. In contrast, Windows RT 8.1 downplays the desktop interface further by not displaying the Desktop tile on the Start screen at all by default (however, it can still be manually pinned to the Start screen by users).

Apps
The suite of pre-loaded apps bundled with Windows 8 were updated for 8.1; PC Settings was expanded to include options that were previously exclusive to the desktop Control Panel, Windows Store was updated with an improved interface for browsing apps and automatic updates, the Mail app includes an updated interface and additional features, the Camera app integrates Photosynth for creating panoramas, and additional editing tools were added to the Photos app (while integration with Flickr and Facebook was completely removed). A number of additional stock apps were also added, including Calculator, Food and Drink, Health and Fitness, Sound Recorder, Reading List (which can be used to collect and sync content from apps through SkyDrive), Scan, and Help + Tips. For Windows RT users, 8.1 also adds a version of Microsoft Outlook to the included Office 2013 RT suite. However, it does not support data loss protection, Group Policy, Lync integration, or creating emails with information rights management. Windows Store is enabled by default within Windows To Go environments.

Online services and functionality
Windows 8.1 adds tighter integration with several Microsoft-owned services. SkyDrive is integrated at the system level to sync user settings and files. Files are automatically downloaded in the background when they are accessed from the user's SkyDrive folder, unless they are marked to be available offline. By default, only file metadata and thumbnails are stored locally, and Reparse points are used to give the appearance of a normal directory structure to provide backwards compatibility. The SkyDrive app was also updated to include a local file manager. However, SkyDrive no longer supports "local" accounts that are not linked to a Microsoft account, and Fetch (a feature which allowed users to remotely retrieve files from their local computer and copy them to SkyDrive) is not available.

A Bing-based unified search system was also added; it can analyze a user's search habits to return results featuring relevant local and online content. Full-screen "hero" displays aggregate news articles, Wikipedia entries, multimedia, and other content related to a search query; for instance, searching for a music performer would return photos of the performer, a biography, and their available songs and albums on Xbox Music. The messaging app from Windows 8 has been replaced by Skype, which also allows users to accept calls directly from the lock screen. Windows 8.1 also includes Internet Explorer 11, which adds support for SPDY and WebGL, and expanded developer tools. The Metro-style version of IE 11 also adds tab syncing, the ability to open an unlimited number of tabs, and Reading List integration.

Security
On compatible hardware, Windows 8.1 also features a transparent "device encryption" system based on BitLocker. Encryption begins as soon as a user begins using the system; the recovery key is stored to either the user's Microsoft account or an Active Directory login, allowing it to be retrieved from any computer. While device encryption is offered on all versions of 8.1 unlike BitLocker (which is exclusive to the Pro and Enterprise editions), device encryption requires that the device meet the Connected Standby specification and have a Trusted Platform Module (TPM) 2.0 chip. 8.1 also introduces improved fingerprint recognition APIs, which allows user login, User Account Control, Windows Store and Windows Store apps to use enrolled fingerprints as an authentication method. A new kiosk mode known as "Assigned Access" was also added, allowing a device to be configured to use a single app in a restricted environment. Additionally, Windows Defender includes an intrusion detection system which can scan network activity for signs of malware. 8.1 also allows third-party VPN clients to automatically trigger connections.

For enterprise device management, Windows 8.1 adds support for the Workplace Join feature of Windows Server 2012 R2, which allows users to enroll their own device into corporate networks with finer control over access to resources and security requirements. 8.1 also supports the OMA Device Management specifications. Remote Data Control can be used to remotely wipe specific "corporate" data from Windows 8.1 devices.

Hardware functionality
Windows 8.1 also adds support for a number of new and emerging technologies, such as 3D printing, pairing with printers using NFC tags, Wi-Fi Direct and Miracast media streaming. Windows 8.1 also adds additional options for scaling display contents on high resolution displays, including a new 200% "Extra Large" mode, and the ability to set scaling settings independently between displays in multi-monitor configurations. 8.1 also adds built-in support for tethering.

Reception
In comparison to the original release of Windows 8, Windows 8.1 received better reviews. While Tom Warren of The Verge still considered the platform to be a "work in progress" (due to the amount of apps available, the impaired level of capabilities that apps have in comparison to desktop programs, and because he felt that mouse and keyboard navigation was still "awkward"), he touted many of the major changes on 8.1, such as the expanded snapping functionality, increased Start screen customization, SkyDrive and Bing integration, improvements to stock apps (in particular, he considered the Mail app to be "lightyears ahead" of the original version from 8), and concluded that "Microsoft has achieved a lot within 12 months, even if a lot of the additions feel like they should have been there from the very start with Windows 8." Peter Bright of Ars Technica praised many of the improvements on 8.1, such its more "complete" touch interface, the "reasonable" tutorial content, the new autocomplete tools on the on-screen keyboard, software improvements, and the deep SkyDrive integration. However, he still felt that the transition between the desktop and apps "still tends to feel a bit disjointed and disconnected" (even though the option to use the desktop wallpaper on the Start screen made it feel more integrated with the desktop interface rather than dissimilar), and that the restoration of the Start button made the two interfaces feel even more inconsistent because of how different it operates between the desktop and apps.

According to data published by Net Applications in November 2013, 8.1 has reached a usage rate of 1.72%, with the usage of stock Windows 8 falling to 7.53% from around 8% in September 2013.

Issues
Shortly after its release, the Windows RT 8.1 update was temporarily recalled by Microsoft following reports that some users had encountered a rare bug which corrupted the operating system's Boot Configuration Data during installation, resulting in an error on startup. On October 21, 2013, Microsoft confirmed that the bug was limited to the Microsoft Surface RT tablet, and only affected 1 in 1000 installations. The company released recovery media and instructions which could be used to repair the device, and restored access to Windows RT 8.1 the next day.

Shortly after its release, it was reported that the changes to screen resolution handling on 8.1 resulted in mouse input lag in certain video games that do not use the DirectInput API's—particularly first-person shooter games like Deus Ex: Human Revolution, Hitman: Absolution, and Metro 2033. Users also found the issues to be more pronounced when using gaming mice with high resolution and/or polling rates. Microsoft released a patch to fix the bug on certain games in November 2013, and acknowledged that it was caused by "changes to mouse-input processing for low-latency interaction scenarios".