Книга: Microsoft Windows Embedded CE 6.0 Exam Preparation Kit

Device Manager

Device Manager

The Windows Embedded CE Device Manager is the OS component that manages the stream device drivers on the system. The OAL (Oal.exe) loads the kernel (Kernel.dll), and the kernel loads Device Manager during the boot process. Specifically, the kernel loads the Device Manager shell (Device.dll), which in turn loads the actual core Device Manager code (Devmgr.dll), which again is in charge of loading, unloading, and interfacing with stream drivers, as illustrated in Figure 6-2.

Figure 6-2 The Device Manager in Windows Embedded CE 6.0

Stream drivers can be loaded as part of the operating system at boot time or on demand when the corresponding hardware is connected in a Plug and Play fashion. User applications can then use the stream drivers through file system APIs, such as ReadFile and WriteFile, or by means of DeviceIoControl calls. Stream drivers that Device Manager exposes through the file system appear to applications as regular file resources with special file names. The DeviceIoControl function, on the other hand, enables applications to perform direct input and output operations. However, applications interact with the stream drivers indirectly through Device Manager in both cases.

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