Windows RT

Windows RT is an edition of the Windows 8 operating system designed for mobile devices that use 32-bit ARM architecture (ARMv7). Microsoft intended for devices with Windows RT to take advantage of the architecture's power efficiency to allow for longer battery life, to use system-on-chip (SoC) designs to allow for thinner devices, and to provide a "reliable" experience over time. In comparison to other mobile operating systems, Windows RT also supports a relatively large number of existing USB peripherals and accessories, and includes a version of Microsoft Office 2013 optimized for ARM devices as pre-loaded software. However, while Windows RT inherits the appearance and functionality of Windows 8, it contains a number of limitations, which includes only being compatible with software obtained from Windows Store, and lacking certain enterprise-oriented features.

First unveiled as a prototype in January 2011 at Consumer Electronics Show, the operating system was officially launched alongside Windows 8 on October 26, 2012, with the release of three Windows RT-based tablets—one of which being Microsoft's own Surface RT tablet. Unlike most other versions of Windows, Windows RT is only available as pre-loaded software on devices specifically designed for the operating system by OEMs. The operating system has only been made available on a total of seven devices, all of which being tablets, with two manufactured by Microsoft itself.

Windows RT was released to mixed reviews from various outlets and critics. Some felt that Windows RT devices had advantages over other mobile platforms (such as iOS or Android) because of its bundled software and the ability to use a wider variety of USB peripherals and accessories. Critics and analysts have deemed Windows RT to be commercially unsuccessful, considering the poor adoption of Windows RT devices by consumers to be a result of its unclear positioning in comparison to Windows 8, its software compatibility limitations (along with a relatively poor selection of apps on launch), and the introduction of Windows 8 devices with battery life and functionality that meet or exceed that of Windows RT devices. As a result, multiple vendors withdrew their future support of the platform, and in August 2013, Microsoft took a loss of US$900 million on poor Surface RT sales. Despite these shortfalls, both Microsoft and Nokia (whose device business is being acquired by Microsoft) introduced new Windows RT products in late-2013.

A lot of students currently replaced the netbooks and self-made laptops into Windows RT.

History
At the 2011 Consumer Electronics Show, it was officially announced that the next version of Windows would provide support for system-on-chips implementing ARM architecture. Windows division president Steven Sinofsky demonstrated an early version of a Windows port for the architecture, codenamed Windows on ARM (WoA), running on prototypes with Qualcomm Snapdragon, Texas Instruments OMAP, and Nvidia Tegra 2 chips. The prototypes featured working versions of Internet Explorer 9 (with DirectX support via the Tegra 2's GPU), Powerpoint and Word, along with the use of class drivers to allow printing to an Epson printer. Sinofsky felt that the shift towards SoC designs were "a natural evolution of hardware that's applicable to a wide range of form factors, not just to slates", while Microsoft CEO Steve Ballmer emphasized the importance of supporting SoCs on Windows by proclaiming that the operating system would "be everywhere on every kind of device without compromise."

Initial development on WoA took place by porting code from Windows 7; Windows Mobile smartphones were used to test early builds of WoA because of lack of readily available ARM-based tablets. Later testing was performed using a custom-designed array of rack-mounted ARM-based systems. Changes to the Windows codebase were made to optimize the OS for the internal hardware of ARM devices, but a number of technical standards traditionally used by x86 systems are also used. WoA devices would use UEFI firmware, and have a software-based Trusted Platform Module to support device encryption and UEFI Secure Boot. ACPI is also used to detect and control plug and play devices and provide power management outside the SoC. To enable wider hardware support, peripherals such as human interface devices, storage and other components that use USB and I²C connections use class drivers and standardized protocols. Windows Update serves as the mechanism for updating all system drivers, software, and firmware.

Microsoft showcased other aspects of the new operating system, to be known as Windows 8, during subsequent presentations. Among these changes (which also included an overhauled interface optimized for use on touch-based devices built around Metro design language) was the introduction of Windows Runtime (WinRT). Software developed using this new architecture could be processor-independent (allowing compatibility with both x86 and ARM-based systems), would emphasize the use of touch input, would run within a sandboxed environment to provide additional security, and be distributed through Windows Store—a store similar to services such as the App Store and Google Play. WinRT was also optimized to provide a more "reliable" experience on ARM-based devices; as such, backwards compatibility for Win32 software otherwise compatible with older versions of Windows was intentionally excluded from Windows on ARM. Windows developers indicated that existing Windows applications were not specifically optimized for reliability and energy efficiency on the ARM architecture, and that WinRT was sufficient for providing "full expressive power" for applications, "while avoiding the traps and pitfalls that can potentially reduce the overall experience for consumers." Consequentially, this lack of backwards compatibility would also prevent existing malware from running on the operating system.

On April 16, 2012, Microsoft announced that Windows on ARM would be officially branded as Windows RT. Microsoft did not explicitly indicate what the "RT" in the operating system's name referred to, but it was believed to refer to the Windows Runtime (RT) architecture. Steven Sinofsky stated that Microsoft would ensure the differences between Windows RT and 8 were adequately addressed in advertising. However, reports found that promotional web pages for the Microsoft Surface tablet had contained confusing wording alluding to the compatibility differences, and that Microsoft Store representatives were providing inconsistent and sometimes incorrect information about Windows RT. In response, Microsoft stated that Microsoft Store staff members would be given an average of 15 hours of training prior to the launch of Windows 8 and Windows RT to ensure consumers are able to make the correct choice for their needs. The first Windows RT devices were officially released alongside Windows 8 on October 26, 2012.

Windows 8.1, a major update for Windows 8 and RT, was released in Windows Store on October 17, 2013, containing a number of improvements to the operating system's interface and functionality. For Windows RT devices, the update also adds Outlook to the included Office RT suite. The update was temporarily recalled by Microsoft shortly after its release, following reports that some Surface RT users had encountered a rare bug which corrupted their device's Boot Configuration Data during installation, resulting in an error on startup. On October 21, 2013, Microsoft released recovery media and instructions which could be used to repair the device, and restored access to Windows 8.1 the next day.

Differences from Windows 8
While Windows RT functions similarly to Windows 8, there are still some notable differences between the two platforms, primarily involving software and hardware compatibility. Julie Larson-Green, executive vice president of the Devices and Studios group at Microsoft, explained that Windows RT was ultimately designed to provide a "closed, turnkey" user experience, "where it doesn't have all the flexibility of Windows, but it has the power of Office and then all the new style applications. So you could give it to your kid and he's not going to load it up with a bunch of toolbars accidentally out of Internet Explorer and then come to you later and say, 'why am I getting all these pop-ups?' It just isn't capable of doing that by design."

Included software
Windows RT does not include Windows Media Player, in favor of other multimedia apps found on Windows Store; devices are pre-loaded with the in-house Xbox Music and Xbox Video apps.

All Windows RT devices include Office 2013 Home & Student RT—a special version of Microsoft Office (consisting of Excel, OneNote, PowerPoint, Word, along with Outlook beginning on 8.1) with optimizations for ARM-based systems. As the version of Office RT included on Windows RT devices is based on the Home & Student version, it cannot be used for "commercial, nonprofit, or revenue-generating activities" unless the organization has a volume license for Office 2013, or the user has an Office 365 subscription with commercial use rights.

Windows RT also includes a BitLocker-based device encryption system, which passively encrypts user data once they sign in with a Microsoft account.

Software compatibility
Due to the differing architecture of ARM-based devices, Windows RT contains limitations in regards to software compatibility. Although the operating system still provides the traditional Windows desktop environment alongside Windows 8's touch-oriented user interface, the only desktop applications officially supported by Windows RT are those that come with the operating system itself; such as File Explorer, Internet Explorer, and Office RT. Only Windows Runtime apps (obtained from Windows Store or sideloaded in enterprise environments) can be installed by users on Windows RT devices. Developers cannot port desktop applications to run on Windows RT, since Microsoft developers felt that they would not be properly optimized for the platform. As a consequence, Windows RT also does not support "new-experience enabled" web browsers; a special class of app used on Windows 8 that allows web browsers to bundle variants that can run in the modern-style user interface and integrate with other apps, but still use Win32 code like desktop programs.

Hardware compatibility
In a presentation at Windows 8's launch event in New York City, Steven Sinofsky claimed that Windows RT would support 420 million existing hardware devices and peripherals. However, in comparison to Windows 8, full functionality will not be available for all devices, and some devices will not be supported at all. Microsoft provides a "Compatibility Center" portal where users can search for compatibility information on devices with Windows RT; on launch, the site listed just over 30,000 devices that were compatible with the operating system.

Networking and device management
While Windows RT devices can join a Homegroup, files cannot be shared directly from the device itself. However, users can still access network shares on other devices within their Homegroup. Windows RT does not support connecting to a domain for network logins, nor does it support using Group Policy for device management. However, Exchange ActiveSync, the Windows Intune service, or System Center Configuration Manager 2012 SP1 can be used to provide some control over Windows RT devices in enterprise environments, such as the ability to apply security policies and provide a portal which can be used to sideload apps from outside Windows Store.

Support lifecycle
Unlike Windows 8 (which, per standard policies for Windows releases, receives around 5 years of mainstream support), Microsoft did not announce any specific date for the end of mainstream support for Windows RT. The Surface tablet falls under Microsoft's support policies for consumer hardware, and will receive mainstream support until April 11, 2017.

Devices


Microsoft imposes tight control on the development and production of Windows RT devices: they are designed in cooperation with the company, and must be built to strict design and hardware specifications, including requirements to only use "approved" models of certain components. To ensure hardware quality and control the number of devices released upon launch, the three participating ARM chip makers were only allowed to partner with up to two PC manufacturers to develop the first "wave" of Windows RT devices in Microsoft's development program. Qualcomm partnered with Samsung and HP, Nvidia with Asus and Lenovo, and Texas Instruments with Toshiba. Additionally, Microsoft partnered with Nvidia to produce Surface RT—the first Windows-based computing device to be manufactured and marketed directly by Microsoft. Windows RT was designed to support chips meeting the ARMv7 architecture, a 32-bit processor platform. Shortly after the original release of Windows RT, ARM Holdings disclosed that it was working with Microsoft and other software partners on supporting the new ARMv8-A architecture, which include a new 64-bit variant, in preparation for future devices.

Multiple hardware partners pulled out of the program during the development of Windows RT; the first being Toshiba and Texas Instruments. TI later announced that it would stop producing ARM products for smartphones and tablets to focus on the embedded systems market. HP also pulled out of the program, believing that Intel-based tablets were more appropriate for business use than ARM. HP was replaced by Dell as an alternate Qualcomm partner. Acer also intended to release a Windows RT device alongside its Windows 8-based products, but initially decided to delay it until the second quarter of 2013 in response to the mixed reaction to Surface. The unveiling of the Microsoft-developed tablet caught Acer by surprise, leading to concerns that Surface could leave "a huge negative impact for the [Windows] ecosystem and other brands."

The first wave of Windows RT devices included:
 * Asus VivoTab RT (released October 26, 2012)
 * Dell XPS 10 (released December 2012, discontinued on September 25, 2013)
 * Lenovo IdeaPad Yoga 11 (released December 2012)
 * Microsoft Surface RT (released October 26, 2012)
 * Samsung Ativ Tab (Released in United Kingdom on December 14, 2012, American and German releases cancelled)

After having planned to produce a Windows RT device close to its launch, Acer's president Jim Wong later indicated that there was "no value" in the current version of the operating system, and would reconsider its plans for future Windows RT products upon the release of the 8.1 update. On August 9, 2013, Asus announced that it would no longer produce any Windows RT products; chairman Johnny Shih expressed displeasure at the market performance of Windows RT, considering it to be "not very promising". During the introduction of its Android and Windows 8-based Venue tablets in October 2013, Dell's vice president Neil Hand stated that the company had no plans to produce an updated version of the XPS 10.

In early-September 2013, Nvidia CEO Jen-Hsun Huang stated that the company was "working really hard" with Microsoft on developing a second revision of Surface. The Microsoft Surface 2 tablet, which is powered by Nvidia's quad-core Tegra 4 platform, was officially unveiled on September 23, 2013, and released on October 22, 2013. On the same day as the Surface 2's release, Nokia (whose mobile business is in the process of being acquired by Microsoft) unveiled the Lumia 2520, a Windows RT tablet with a Qualcomm Snapdragon 800 processor, LTE, and a design similar to its line of Windows Phone products.

Reception
Windows RT's launch devices received mixed reviews upon their release. Within a review of the Asus VivoTab RT by PC Advisor, Windows RT was praised for being a mobile operating system that still offered some PC amenities such as a full-featured file manager, but noted its lack of compatibility with existing Windows software, and that it had no proper media player aside from a "shameless, in-your-face conduit to Xbox Music." AnandTech believed Windows RT was the first "legitimately useful" mobile operating system, owing in part to its multitasking system, bundled Office programs, smooth interface performance, and "decent" support for a wider variety of USB devices in comparison to other operating systems on the ARM architecture. However, the OS was panned for its slow application launch times in comparison to a recent iPad, and spotty driver support for printers. The small number of "quality" apps available on launch was also noted—but considered to be a non-issue "[because] you can basically assume that the marketplace will expand significantly unless somehow everyone stops buying Windows-based systems on October 26th."

Reception of the preview release of RT 8.1 was mixed; both ExtremeTech and TechRadar praised the improvements to the operating system's tablet-oriented interface, along with the addition of Outlook; TechRadar's Dan Grabham believed that the inclusion of Outlook was important because "nobody in their right mind would try and handle work email inside the standard Mail app—it's just not up to the task." However, both experienced performance issues running the beta on the Tegra 3-based Surface RT; ExtremeTech concluded that "as it stands, we’re still not sure why you would ever opt to buy a Windows RT tablet when there are similarly priced Atom-powered x86 devices that run the full version of Windows 8."

Market relevance and response
The need to market an ARM-compatible version of Windows was questioned by analysts because of recent developments in the PC industry; both Intel and AMD introduced x86-based system-on-chip designs for Windows 8, Atom "Clover Trail" and "Temash" respectively, in response to the growing competition from ARM licensees. In particular, Intel claimed that Clover Trail-based tablets could provide battery life rivaling that of ARM devices; in a test by PC World, Samsung's Clover Trail-based Ativ Smart PC was shown to have battery life exceeding that of the ARM-based Surface RT. Peter Bright of Ars Technica argued that Windows RT had no clear purpose, since the power advantage of ARM-based devices was "nowhere near as clear-cut as it was two years ago", and that users would be better off purchasing Office 2013 themselves because of the removed features and licensing restrictions of Office RT.

Windows RT has also been met with lukewarm reaction from manufacturers; in June 2012, Hewlett-Packard cancelled its plans to release a Windows RT tablet, stating that its customers felt Intel-based tablets were more appropriate for use in business environments. In January 2013, Samsung cancelled the American release of its Windows RT tablet, the Ativ Tab, citing the unclear positioning of the operating system, "modest" demand for Windows RT devices, plus the effort and investment required to educate consumers on the differences between Windows 8 and RT as reasons for the move. Mike Abary, senior vice president of Samsung's U.S. PC and tablet businesses, also stated that the company was unable to build the Ativ Tab to meet its target price point—considering that lower cost was intended to be a selling point for Windows RT devices. Nvidia CEO Jen-Hsun Huang expressed disappointment over the market performance of Windows RT, but called on Microsoft to continue increasing its concentration on the ARM platform. Huang also commented on the exclusion of Outlook from the Office 2013 suite included on the device, and suggested that Microsoft port the software for RT as well (in response to public demand, Microsoft announced the inclusion of Outlook with future versions of Windows RT in June 2013). In May 2013, reports surfaced that HTC had scrapped plans to produce a 12-inch Windows RT tablet as it would cost too much to produce, and that there would be greater demand for smaller devices (which it planned to produce instead).

The poor demand resulted in price cuts for various Windows RT products; in April 2013 the price of Dell's XPS 10 fell from US$450 US to $300, and Microsoft began offering free covers for its Surface tablet in some territories as a limited-time promotion—itself a US$130 value for the Type Cover alone. Microsoft also reportedly reduced the cost of Windows RT licenses for devices with smaller screens, hoping that this could spur interest in the platform. In July 2013, Microsoft cut the price of the Surface RT worldwide by 30%, with its U.S. price falling to $350. Concurrently, Microsoft reported a loss of US$900 million due to the lackluster sales of the device. In August 2013, Dell silently pulled the option to purchase the XPS 10 from its online store without a keyboard dock (raising its price back up to US$479), and pulled the device entirely in September 2013. Microsoft's discount on the Surface RT did result in a slight increase of market share for the device; in late-August 2013, usage data from the advertising network AdDuplex (which provides advertising services within Windows Store apps) revealed that Surface RT usage had increased from 6.2 to 9.8%.

In November 2013, speaking about Windows RT at the UBS Global Technology Conference, Julie Larson-Green made comments discussing the future of Microsoft's mobile strategy surrounding the Windows platform. Larson-Green stated that in the future (accounting for Windows, Windows RT, and Windows Phone), Microsoft was "[not] going to have three [mobile operating systems]." The fate of Windows RT was left unclear by her remarks; industry analysts interpreted them as signs that Microsoft was preparing to discontinue Windows RT due to its poor adoption, while others suggested that Microsoft was planning to unify Windows and Windows Phone.

Restrictions and compatibility limitations
In contrast to Windows 8 (where the feature had to be enabled by default, but remain user-configurable), Microsoft requires all Windows RT devices to have UEFI Secure Boot permanently enabled. The decision was criticized for harming user choice by preventing the installation of alternative operating systems such as Linux; however, Tom Warren of The Verge noted that other recent smartphones and tablets have been sold in a similarly locked-down state, including those with Microsoft's own Windows Phone operating system.

The requirement to obtain most software on Windows RT through Windows Store was considered to be similar in nature to the application stores on other "closed" mobile platforms; where only software certified under guidelines issued by the vendor (i.e. Microsoft) can be distributed in the store. Microsoft was also criticized by the developers of the Firefox web browser for effectively preventing the development of third-party web browsers for Windows RT (and thus forcing use of its own Internet Explorer browser) by restricting the development of desktop applications and by not providing the same APIs and exceptions available on Windows 8 to code web browsers that can run as apps. However, the European Union, in response to a complaint about the restrictions in relation to an antitrust case involving Microsoft, ruled that "so far, there are no grounds to pursue further investigation on this particular issue." As mandated by the EU, the BrowserChoice.eu service is still included in Windows 8.

"Jailbreak" exploit
In January 2013, a privilege escalation exploit was discovered in the Windows kernel that can allow unsigned code to run under Windows RT; the exploit involved the use of a remote debugging tool (provided by Microsoft to debug WinRT apps on Windows RT devices) to execute code which changes the signing level stored in RAM to allow unsigned code to execute (by default, it is set to a level that only allows code signed by Microsoft to execute). Alongside his explanation of the exploit, the developer also included a personal appeal to Microsoft urging them to remove the restrictions on Windows RT devices, contending that their decision was not for technical reasons, and that the devices would be more valuable if this functionality were available. In a statement, a Microsoft spokesperson applauded the effort, indicating that the exploit does not pose a security threat because it requires administrative access to the device, advanced techniques, and would still require programs to be re-compiled for ARM. However, Microsoft has still indicated that the exploit would be patched in a future update.

A batch file-based tool soon surfaced on XDA Developers to assist users in the process of performing the exploit, and a variety of ported desktop applications began to emerge, such as the emulator Bochs, PuTTY and TightVNC. Afterwards, an emulator known as "Win86emu" surfaced, allowing users to run x86 software on a jailbroken Windows RT device. However, it does not support all Windows APIs, and runs programs slower than they would on a native system.