CROSSREF. Check out Chapter 3 for more information about Metro and its multi‑touch interactions.

Check out Chapter 3 for more information about Metro and its multi‑touch interactions.

Connected Standby

While Windows’s support for power management has evolved over the years, the new emphasis on highly portable computing in Windows 8 has triggered the development of an excellent new power management mode called Connected Standby. This mode isn’t generally available on PCs created before 2012 and is designed for new, highly portable devices that will only rarely be turned off. In other words, it works much like power management on a modern smartphone.

Instead of using a standard sleep state, Connected Standby allows your PC or device to enter a nearly powerless state in which battery life is only minimally impacted but Metro‑style apps can run in the background, performing tasks like updating e‑mail and triggering notifications. Of course, traditional desktop applications are unaware of this new power mode, so Windows 8 utilizes a new Desktop Activity Monitor to reduce the resource utilization of desktop applications while in this mode.

Connected Standby is available in all Windows 8 versions, including Windows RT, but will work best on new hardware designed specifically for this mode. But even if your PC or device doesn’t support Connected Standby, Windows 8 includes numerous power management improvements that should improve battery life and performance when compared to performing similar tasks in Windows 7.

Sensors

Many of Windows 8’s new capabilities are inspired by smartphones and other highly mobile devices and the new wireless scenarios these devices enable. Key among these capabilities is a support for a variety of sensors, small hardware devices that provide interaction between the outside world and Windows itself. Some of the new scenarios supported by Windows 8 and sensors include:

• Adaptive screen brightness control: In the past, controlling screen brightness was at best semi‑automatic. You could manually configure a brightness setting in Power Options. Or those with portable computers could use power modes to automatically change the screen brightness to one of two settings, depending on whether the machine was attached to power. In Windows 8, the situation is much more sophisticated, and if you have a PC or device with an ambient light sensor (ALS), Windows 8 will automatically change the brightness of the screen on the fly. This capability is better for your eyes and for readability, but it can also improve battery life when you use the PC or device in a dimly lit area.

• Automatic screen rotation: Tablets and hybrid devices and other screens can utilize an accelerometer to determine the orientation of the screen and rotate the on‑screen display appropriately as it’s changed. This type of activity is common on smartphones and, with Windows 8, it’s come to PCs as well.

• Tilt and motion: Using a gyroscope sensor, a Windows 8‑based PC or tablet can register its movements in 3‑D space, providing feedback to games and apps. In this way, you might tilt a tablet forward to accelerate during a driving game, or tilt the device to the left and right to steer. This isn’t limited to just games, however, and the types of motions gyroscope sensors can detect–including shakes, twists, and rotations in multiple dimensions–are quite sophisticated.

• Location and directions: Using a standard GPS sensor, a Windows 8 PC or device can accurately report its geographic location and then plot routes and distances to other destinations. Mapping and driving apps are obvious applications for this capability.

• Compass: Using a 3‑D accelerometer and a 3‑D magnetometer, or a gyroscope, a Windows 8 PC or device can emulate a compass. In fact, they can be used to create a multi‑axis, tilt‑sensitive compass.

Tap to Send (NFC)

Utilizing new Near Field Communication (NFC) chipsets, Windows 8‑based PCs and devices can send content to another compatible device (Windows 8 PC or device, Windows Phone 8, or other NFC‑compatible device) using a new method called Tap to Send. This method additionally requires a unique tap zone on the device’s exterior, which is used to initiate a send or receive action, but even without this part, NFC can still be used via Bluetooth to send information wirelessly.

So what’s the big deal with NFC? As an emerging standard, NFC is being used to perform contactless (that is, wireless) payments at retail locations, data exchanges, and other duties. And while these activities may seem better suited to a smartphone, the inclusion of NFC in Windows 8 means that these PCs and devices will be able to participate with coming NFC‑based systems as well.

UEFI Firmware

New Windows 8‑based PCs and devices will utilize a new type of firmware called Unified Extensible Firmware Interface, or UEFI, instead of the old‑fashioned BIOS firmware we’ve been using for decades. UEFI provides many advantages over BIOS, but key among them is performance: UEFI‑based PCs and devices will boot much more quickly than those based on BIOS.

UEFI offers other advantages over BIOS, of course. The user interface for this firmware type can be graphical instead of text‑based like BIOS. And it enables a new security feature called Secure Boot that protects system components from tampering during boot.