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This section discusses the Device Manager, its position within the Windows CE OS, and its management of stream interface drivers. Developers do not need in-depth knowledge of the Device Manager in order to write device drivers, but a general understanding of the Device Manager and its role within Windows CE is useful.
The Device Manager, which is a user-level process, runs continuously on a Windows CE–based platform. The Device Manager is not part of the kernel, but it is a separate application that interacts with the kernel, the registry, and stream interface driver DLLs. More specifically, the Device Manager performs the following tasks:
- Detects that a user has attached a peripheral to the Windows CE–based platform, and attempts to load a device driver for the peripheral. For example, when a user inserts a PC Card, the Device Manager attempts to locate and load a device driver for that PC Card.
- Registers special file names with the kernel that map the stream I/O functions that are used by applications to the implementations of those functions within a stream interface driver.
- Finds the appropriate device driver for a peripheral by obtaining a Plug and Play identifier from the peripheral device or by invoking a detection routine to find a driver that can handle the device.
- Loads and tracks drivers by reading and writing registry values.
- Unloads drivers when their devices are no longer needed. For
example, the Device Manager unloads a PC Card device driver when a
user removes the card.
Last updated on Tuesday, July 13, 2004