Windows 8 On ARM
Microsoft executive Steven Sinofsky today outlined what developers and users can expect from Windows 8 on ARM (WOA) devices.
Microsot plans to release Windows 8 in x86/64 and ARM
devices. We have summarized the basic facts of the WOA experience.
Microsoft says that using WOA "out of the box" will feel just like using Windows 8 on x86/64. Signing in, running apps, accessing the new Windows Store (apps) the start screen, the Metro style apps, the Internet Explorer and the Windows desktop will be the same, as the Windows 8 in x86/64.
The company plans to ship WOA PCs at the same time as PCs designed for Windows 8 on x86/64. These PCs will be built on hardware platforms provided by NVIDIA, Qualcomm, and Texas Instruments, with a common Windows on ARM OS foundation - all running the same Windows OS binaries - a unique approach for the industry.
Metro style apps found in Microsoft's Windows Store will support both WOA and Windows 8 on x86/64. Developers wishing to target WOA will do so by writing applications for the WinRT (Windows APIs for building Metro style apps) using the new Visual Studio 11 tools in a variety of languages, including C#/VB/XAML and Jscript/ HTML5. Native code targeting WinRT is also supported using C and C++, which can be targeted across architectures and distributed through the Windows Store. WOA does not support running, emulating, or porting existing x86/64 desktop apps. Code that uses only system or OS services from WinRT can be used within an app and distributed through the Windows Store for both WOA and x86/64. Users will obtain all software, including device drivers, through the Windows Store and Microsoft Update or Windows Update, Microsoft said.
WOA will support all new Metro style apps, including apps from Microsoft for mail, calendaring, contacts, photos, and storage. WOA also includes support for hardware-accelerated HTML5 with Internet Explorer 10. WOA will also provide support for other industry-standard media formats, including those with hardware acceleration and offloading computation, and industry-standard document formats. WOA includes desktop versions of the new Microsoft Word, Excel, PowerPoint, and OneNote. These new Office applications, codenamed "Office 15", have been architected for both touch and minimized power/resource consumption, while also being fully-featured for users and providing complete document compatibility. WOA supports the Windows desktop experience including File Explorer, Internet Explorer 10 for the desktop, and most other intrinsic Windows desktop features - which have been architected for both touch and minimized power/resource consumption.
Microsoft's partners will provide WOA PCs as integrated, end-to-end products that include hardware, firmware, and Windows on ARM software. Windows on ARM software will not be sold or distributed independent of a new WOA PC.
Around the next milestone release of Windows 8 on x86/64, Microsoft will provide a limited number of test PCs to developers in a closed, invitation-only program. These are tools for hardware and software engineers running WOA-specific hardware. The Windows Consumer Preview, the beta of Windows 8 on x86/64, will be available for download by the end of February.
WOA will also include the Windows desktop, which offers users a familiar place to interact with PCs, particularly files, storage, and networking, as well as a range of peripherals. Users will be able to use Windows Explorer, for example, to connect to external storage devices, transfer and manage files from a network share, or use multiple displays, and do all of this with or without an attached keyboard and mouse. They'll have access to a deep array of control panel settings to customize and access a finer-grained level of control over their system.
At the same time, WOA (as with Windows 8) is designed so that users focused on Metro style apps don't need to spend time in the desktop.
One of the new aspects of WOA is that it will not turn off a WOA PC. WOA PCs will not have the traditional hibernate and sleep options with which we are familiar. Instead, WOA PCs always operate in the newly designed Connected Standby power mode, similar to the way we are using in a mobile phone today. When the screen is on, users have access to the full power and capabilities of the WOA PC. When the screen goes dark (by pressing the power button or timer), the PC enters a new, very low-power mode that enables the battery to last for weeks. For end-users, a new capability of WOA is that they are in control of what programs have access to background execution so that those apps are always connected, and information like new mail is always up to date. Connected Standby permeates the engineering for WOA PCs from the hardware through the firmware, OS, WinRT platform, and apps. Connected Standby won't be limited to the ARM architecture and Microsoft is working on these capabilities for x86/64 SoC products as well.
By design, ARM systems are not standardized - each device from each manufacturer is unique and the software that runs on that device is unique. There is of course a standard instruction set and CPU architecture, but many of the connections between the CPU and other components are part of the innovation each licensee brings to the ARM platform. End-users will be technically restricted from installing a different OS (or OS version) on a device or extending the OS, so this is generally not possible, and rarely supported by the device maker. Device makers work with ARM partners to create a device that is strictly paired with a specific set of software (and sometimes vice versa), and consumers purchase this complete package, which is then serviced and updated through a single pipeline. In these ways, this is all quite different than the Windows on x86/64 world.
Microsoft's device strategy uses standardized protocols and class drivers extensively:
- Low power serial busses such as I2C / UART will be normal on ARM PCs and less common on x86 PCs.
- SD I/O will allow users to connect low power Wi-Fi radios. Radios in current PCs are connected via USB or PCI-E. Microsoft added SD I/O support to preserve high data rates (100 MB/s) while still improving battery life. Wi-Fi support on WOA also allows efficient offloading to maintain connections in connected standby while using very little power.
- Embedded MultiMediaCard storage (eMMC) is a de facto standard for storage on ARM devices (since most do not support SATA). In addition to supporting eMMC, Microsoft made several OS performance optimizations to reduce and coalesce storage I/O, resulting in fewer reads and writes to storage.
- The General Purpose I/O (GPIO) driver supports connecting buttons, interrupts or other I/O to the ARM processor. In addition to the GPIO driver, there?s also a button driver for the Windows, power, and volume buttons.
ARM SoCs for WOA will also have DirectX capable GPUs (DX) for accelerated graphics in Internet Explorer 10, in the user interface of Windows, and in Metro style apps.
WOA PCs use hardware support for offloading specific work from the main processor to integrated hardware subsystems. This improves performance and battery life. For example, while watching a movie, the processing is done with multimedia offload (to a dedicated processor for example), and all other processing is minimized.
The services that will support the full breadth of Windows are common across the architectures, so that developers can take advantage of them in Metro style apps:
- Mobile broadband (MBB) class driver. By creating a class driver, Microsoft made it much easier to add broadband capability to all Windows PCs.
- Printer class driver. For Windows 8, Microsoft rearchitected the print infrastructure to add class driver support. The majority of printers selling today are supported using the class driver, which means users will be able to "plug and print" on WOA without additional drivers.
- GPS. Windows offers a location provider that can triangulate a PC's location via Wi-Fi access points and a backing database. In addition, systems that have Mobile Broadband will also have integrated Global Navigation Satellite System (GNSS, aka GPS in the US) receivers to provide accurate location while navigating outdoors.
- Sensors (accelerometer, rotation, gyro, compass, magnetometer). Mirosoft has added support for sensors in SoC-based architectures and utilizes the HID over I2C protocol.
- Bluetooth. WOA supports Bluetooth LE and the same profiles as Windows 8 on x86/64 and connectivity to the Bluetooth radio using low-power UART.
- MTP over USB and IP. Windows on ARM provides users with the ability to connect their portable devices (like mobile phones, music players, cameras) to their systems using the Media Transfer Protocol (MTP). These MTP-compliant devices can connect over USB or IP by leveraging inbox Windows class drivers, and allow users to exchange data with their favorite Metro style apps.
- Windows Update-based servicing. For all platform code (OS, drivers, system and device firmware), each WOA system will be serviced through Windows Update (WU), from top to bottom. Microsoft has added support in WU for updating the system firmware on WOA systems, as well as driver targeting, which means that each device will get the drivers that have been verified to work best with it.
Previously Microsoft has detailed that WOA will not support any type of virtualization or emulation approach, and will not enable existing x86/64 applications to be ported or run.
"If you need to run existing x86/64 software, then you will be best served with Windows 8 on x86/64. If you're already considering a non-Windows device, then we think WOA will be an even better alternative when you consider the potential of form factors, peripherals, Windows Store apps (and developer platform), and Office applications as well as a broad set of intrinsic Windows capabilities," Microsoft said.
Developers wanting to reach WOA with existing apps will have two options. Many apps will be best served by building new Metro style front ends for existing data sources or applications, and communicating through a web services API. Of course, these do not need to be just front-ends, but could operate on local data too, since WOA provides full access to files and peripherals. Other existing applications will be served by reusing large amounts of engine or runtime code, and surrounding that with a Metro style experience.
WOA PCs will be serviced only through Windows or Microsoft Update, and consumer apps will only come from the Windows Store, so users never have to worry if a program will run because they are not downloading or installing from a DVD outside of the store experience.
Microsoft says that using WOA "out of the box" will feel just like using Windows 8 on x86/64. Signing in, running apps, accessing the new Windows Store (apps) the start screen, the Metro style apps, the Internet Explorer and the Windows desktop will be the same, as the Windows 8 in x86/64.
The company plans to ship WOA PCs at the same time as PCs designed for Windows 8 on x86/64. These PCs will be built on hardware platforms provided by NVIDIA, Qualcomm, and Texas Instruments, with a common Windows on ARM OS foundation - all running the same Windows OS binaries - a unique approach for the industry.
Metro style apps found in Microsoft's Windows Store will support both WOA and Windows 8 on x86/64. Developers wishing to target WOA will do so by writing applications for the WinRT (Windows APIs for building Metro style apps) using the new Visual Studio 11 tools in a variety of languages, including C#/VB/XAML and Jscript/ HTML5. Native code targeting WinRT is also supported using C and C++, which can be targeted across architectures and distributed through the Windows Store. WOA does not support running, emulating, or porting existing x86/64 desktop apps. Code that uses only system or OS services from WinRT can be used within an app and distributed through the Windows Store for both WOA and x86/64. Users will obtain all software, including device drivers, through the Windows Store and Microsoft Update or Windows Update, Microsoft said.
WOA will support all new Metro style apps, including apps from Microsoft for mail, calendaring, contacts, photos, and storage. WOA also includes support for hardware-accelerated HTML5 with Internet Explorer 10. WOA will also provide support for other industry-standard media formats, including those with hardware acceleration and offloading computation, and industry-standard document formats. WOA includes desktop versions of the new Microsoft Word, Excel, PowerPoint, and OneNote. These new Office applications, codenamed "Office 15", have been architected for both touch and minimized power/resource consumption, while also being fully-featured for users and providing complete document compatibility. WOA supports the Windows desktop experience including File Explorer, Internet Explorer 10 for the desktop, and most other intrinsic Windows desktop features - which have been architected for both touch and minimized power/resource consumption.
Microsoft's partners will provide WOA PCs as integrated, end-to-end products that include hardware, firmware, and Windows on ARM software. Windows on ARM software will not be sold or distributed independent of a new WOA PC.
Around the next milestone release of Windows 8 on x86/64, Microsoft will provide a limited number of test PCs to developers in a closed, invitation-only program. These are tools for hardware and software engineers running WOA-specific hardware. The Windows Consumer Preview, the beta of Windows 8 on x86/64, will be available for download by the end of February.
WOA will also include the Windows desktop, which offers users a familiar place to interact with PCs, particularly files, storage, and networking, as well as a range of peripherals. Users will be able to use Windows Explorer, for example, to connect to external storage devices, transfer and manage files from a network share, or use multiple displays, and do all of this with or without an attached keyboard and mouse. They'll have access to a deep array of control panel settings to customize and access a finer-grained level of control over their system.
At the same time, WOA (as with Windows 8) is designed so that users focused on Metro style apps don't need to spend time in the desktop.
One of the new aspects of WOA is that it will not turn off a WOA PC. WOA PCs will not have the traditional hibernate and sleep options with which we are familiar. Instead, WOA PCs always operate in the newly designed Connected Standby power mode, similar to the way we are using in a mobile phone today. When the screen is on, users have access to the full power and capabilities of the WOA PC. When the screen goes dark (by pressing the power button or timer), the PC enters a new, very low-power mode that enables the battery to last for weeks. For end-users, a new capability of WOA is that they are in control of what programs have access to background execution so that those apps are always connected, and information like new mail is always up to date. Connected Standby permeates the engineering for WOA PCs from the hardware through the firmware, OS, WinRT platform, and apps. Connected Standby won't be limited to the ARM architecture and Microsoft is working on these capabilities for x86/64 SoC products as well.
By design, ARM systems are not standardized - each device from each manufacturer is unique and the software that runs on that device is unique. There is of course a standard instruction set and CPU architecture, but many of the connections between the CPU and other components are part of the innovation each licensee brings to the ARM platform. End-users will be technically restricted from installing a different OS (or OS version) on a device or extending the OS, so this is generally not possible, and rarely supported by the device maker. Device makers work with ARM partners to create a device that is strictly paired with a specific set of software (and sometimes vice versa), and consumers purchase this complete package, which is then serviced and updated through a single pipeline. In these ways, this is all quite different than the Windows on x86/64 world.
Microsoft's device strategy uses standardized protocols and class drivers extensively:
- Low power serial busses such as I2C / UART will be normal on ARM PCs and less common on x86 PCs.
- SD I/O will allow users to connect low power Wi-Fi radios. Radios in current PCs are connected via USB or PCI-E. Microsoft added SD I/O support to preserve high data rates (100 MB/s) while still improving battery life. Wi-Fi support on WOA also allows efficient offloading to maintain connections in connected standby while using very little power.
- Embedded MultiMediaCard storage (eMMC) is a de facto standard for storage on ARM devices (since most do not support SATA). In addition to supporting eMMC, Microsoft made several OS performance optimizations to reduce and coalesce storage I/O, resulting in fewer reads and writes to storage.
- The General Purpose I/O (GPIO) driver supports connecting buttons, interrupts or other I/O to the ARM processor. In addition to the GPIO driver, there?s also a button driver for the Windows, power, and volume buttons.
ARM SoCs for WOA will also have DirectX capable GPUs (DX) for accelerated graphics in Internet Explorer 10, in the user interface of Windows, and in Metro style apps.
WOA PCs use hardware support for offloading specific work from the main processor to integrated hardware subsystems. This improves performance and battery life. For example, while watching a movie, the processing is done with multimedia offload (to a dedicated processor for example), and all other processing is minimized.
The services that will support the full breadth of Windows are common across the architectures, so that developers can take advantage of them in Metro style apps:
- Mobile broadband (MBB) class driver. By creating a class driver, Microsoft made it much easier to add broadband capability to all Windows PCs.
- Printer class driver. For Windows 8, Microsoft rearchitected the print infrastructure to add class driver support. The majority of printers selling today are supported using the class driver, which means users will be able to "plug and print" on WOA without additional drivers.
- GPS. Windows offers a location provider that can triangulate a PC's location via Wi-Fi access points and a backing database. In addition, systems that have Mobile Broadband will also have integrated Global Navigation Satellite System (GNSS, aka GPS in the US) receivers to provide accurate location while navigating outdoors.
- Sensors (accelerometer, rotation, gyro, compass, magnetometer). Mirosoft has added support for sensors in SoC-based architectures and utilizes the HID over I2C protocol.
- Bluetooth. WOA supports Bluetooth LE and the same profiles as Windows 8 on x86/64 and connectivity to the Bluetooth radio using low-power UART.
- MTP over USB and IP. Windows on ARM provides users with the ability to connect their portable devices (like mobile phones, music players, cameras) to their systems using the Media Transfer Protocol (MTP). These MTP-compliant devices can connect over USB or IP by leveraging inbox Windows class drivers, and allow users to exchange data with their favorite Metro style apps.
- Windows Update-based servicing. For all platform code (OS, drivers, system and device firmware), each WOA system will be serviced through Windows Update (WU), from top to bottom. Microsoft has added support in WU for updating the system firmware on WOA systems, as well as driver targeting, which means that each device will get the drivers that have been verified to work best with it.
Previously Microsoft has detailed that WOA will not support any type of virtualization or emulation approach, and will not enable existing x86/64 applications to be ported or run.
"If you need to run existing x86/64 software, then you will be best served with Windows 8 on x86/64. If you're already considering a non-Windows device, then we think WOA will be an even better alternative when you consider the potential of form factors, peripherals, Windows Store apps (and developer platform), and Office applications as well as a broad set of intrinsic Windows capabilities," Microsoft said.
Developers wanting to reach WOA with existing apps will have two options. Many apps will be best served by building new Metro style front ends for existing data sources or applications, and communicating through a web services API. Of course, these do not need to be just front-ends, but could operate on local data too, since WOA provides full access to files and peripherals. Other existing applications will be served by reusing large amounts of engine or runtime code, and surrounding that with a Metro style experience.
WOA PCs will be serviced only through Windows or Microsoft Update, and consumer apps will only come from the Windows Store, so users never have to worry if a program will run because they are not downloading or installing from a DVD outside of the store experience.
