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Drivers for Multiple Cards

This section describes two cases where drivers have to deal with multiple cards. They are the following:

The first case in which a driver may need to support multiple instances of the same PCI expansion card. In that case, the CFM and Driver Loader Library (DLL)do all the work and you will get a separate CFM instance of the driver for each card. The CFM links instances of the native driver on the fly when the driver is loaded by the DLL.

The second case where a driver needs to support different, but related PCI expansion cards (or multiple functions on one card). In this case the driver should use the Code Fragment Manager to import a shared library for both code and data.

Follow these design guidelines:

• Put the shared library in the Extensions folder in the System Folder.
• Separate your code and data into card-specific and card-independent portions. Card-specific portions go into the driver, and card-independent portions go into the library.
• Some family experts like the OpenTransport and the USB version 1.2 or greater experts support the extended 'cfrg' resource. The extended resource allows merging of multiple drivers files in a single 'ndrv' file. See the documentation for the specific device family for further information about how this is done.

You can construct a driver that exports services for different families, such as both 'ndrv' and 'otan', using a driver description structure with multiple service categories defined.