Professional Windows® Embedded Compact 7

LOADING A DRIVER

How and when a Stream Interface Driver (Stream Driver) loads depends much on the purpose of the driver and its registry settings. As a lead into Stream Drivers, this section examines what happens when you load any driver.

When Is a Driver Loaded?

A Windows Embedded Compact 7 device driver is either loaded at startup, when the device is physically connected to the system if it is “plug and play” or when an application initiates the loading. Some devices automatically load at startup because the system requires them for a dedicated function such as a display. Some devices load at startup because the system is configured to attempt to load them at startup if physically present in the system. Other devices load at startup because a bus driver finds them. Devices can also be loaded by a bus driver at later stage when they are inserted into the device. Alternatively, applications may initiate their loading.

Registry

As previously discussed, each driver is loaded by one of the managers GWES, FileSys, or Device Manager. These make use of the system registry to identify the device, its DLL, and its required parameters. If the device isn’t listed in the registry, it can’t be loaded, although drivers loaded programmatically can use registry settings written in advance by the application. The registry is a special storage location on a Windows device that acts as a database of the hardware, software, and users of the device. Device driver registry details are stored under ...