The following illustration shows the relationship between the legacy and the new 1394 bus drivers. For more information about some known differences in behavior between the new bus driver and the legacy 1394 bus drivers, see IEEE 1394 Bus Driver in Windows 7. The 1394ohci.sys bus driver is fully backward compatible with the legacy 1394 bus drivers. In Windows 7 and later versions, the legacy port/miniport bus drivers are replaced by 1394ohci.sys, a monolithic IEEE 1394 bus driver that is implemented by using the kernel-mode driver framework (KMDF). Before Windows 7, the bus driver was a combination of a port driver (1394bus.sys) and a primary miniport driver for the motherboard's host controller (ochi1394.sys). The device driver communicates with the device by sending IRPs, which are processed by the IEEE 1394 bus driver. The bus driver provides a hardware-independent interface to the IEEE 1394 bus.

The following diagram illustrates the IEEE 1394 driver stack with the new 1394 bus driver and the Microsoft-supported 1394 client drivers.Ī client driver for a device that connects to the IEEE 1394 bus driver sits on top of the IEEE 1394 driver stack.

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