Datasheet

The number of processes has been increased from 32 to 32K (32,768). This is important
to application developers. On Windows Mobile 6.x, only 32 processes can be active at
the same time. If a user wants to launch another process, the system will reject it. WP7
eliminates the 32-process limitation.
User mode and kernel mode device drivers are possible.
device.exe, filesys.exe, and GWES.exe have been moved to Kernel mode, to improve
device performance.
Overall, the operating system in WP7 devices is more secure and stable, and offers better
performance.
Figure 1-1 illustrates the WP7 OS architecture. As shown in the fi gure, the operating system contains
three layers (from bottom to top): hardware, kernel space, and user space. All .NET Framework
applications run in the user space. The OS kernel, drivers, and system services execute in kernel
space. Compared to the architecture of Windows Mobile 6.5, on which you can execute both native
and managed applications, WP7 OS enforces managed application development only. Furthermore,
managed applications can use only the features provided by Silverlight, XNA, and Phone APIs;
nothing else is accessible from within applications.
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Applications
Silverlight
User space
Kernel space
Sensors
Phone
Xbox LIVE
.Net Framework
CE Kernel
Networking
Phone
update
File system
Graphics
OAL
Drivers
Hardware
Notifications
Location Media
Data
XNA
FIGURE 1-1: WP7 architecture
An Overview of Windows Phone 7
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