Configuration Manager 2007 Advanced Client and Write Filters
8/29/2011
Configuration Manager 2007 Advanced Client behaves normally when write filters are not enabled on computers running Windows XP Embedded. However, when write filters are enabled, there are differences in functionality depending on which write filters are used.
Configuration Manager 2007 Advanced Client utilizes many Windows components on the computer on which it is installed, including Windows Management Infrastructure (WMI), Background Intelligent Transfer Service (BITS), and Windows Server Update Services (WSUS). Both the Configuration Manager 2007 Advanced Client and these Windows components store installation and state information in the registry, as well as on the primary storage device of the computer or device. In addition, other folders, files, and registry keys can be modified during the installation of software or software updates on a Configuration Manager 2007 Advanced Client. Windows XP Embedded write filters are designed to take registry and file changes, store them in an overlay, and then discard that overlay when the device restarts. Depending on which write filter you use, the implications of write filters are different for the Configuration Manager 2007 Advanced Client and any Windows components that the client utilizes.
Configuration Manager 2007 Advanced Client makes frequent writes to the registry and to the storage drive as part of its normal functioning, including hardware and software inventory, policy download and evaluation, software distribution, and software update management. To manage registry exceptions, see the Registry Exceptions section of this page. Enhanced Write Filter (EWF) can be used to filter writes at a sector level on protected disks. Computers running Windows XP Embedded do not allow you to commit these changes. Before using Configuration Manager 2007 to distribute software or software updates to devices running Windows XP Embedded with EWF enabled, you must ensure that the write filter is disabled, perform the software updates, and then enable write filters. This may require you to reboot the computer multiple times. For more information, see How to Manage Windows Embedded Write Filters.