The Windows 7 1394 has a new default driver. The default binary is 1394OHCI.sys (KMDF) driver. Windows 7 also comes with, but not loaded, the Legacy Window OHCI1394.sys and 1394bus.sys drivers. Below is a listing of some of the key enhancements to be aware of from the new driver.
* 1394OHCI.sys is now the default Windows 7 2008/r2 driver.
** Requires 1394A PHY or 1394b cards.
** Offers Gap Count Optimization which provides a big improvement in performance.
As the legacy drivers are included you can use Device Manager to switch between Legacy and default driver. To swap go into Device Manager and uninstall the 1394OHCI and manually add the legacy driver and restart. To know if Windows 7 user has loaded the legacy stack you can look in Device Manger which identifies the currently loaded driver(s) and version numbers.
** New driver does not support 1394-1995 PHY. These older cards would cause the driver to bang out on startup. Legacy driver maybe required to resolve this.
More details about the new Windows 7 1394 stack can be found in the “1394 Bus Driver in Windows 7” whitepaper available for download from http://www.microsoft.com/whdc/connect/1394_Windows7.mspx .