File Based Write Filter (Fbwf) - Siemens SIMATIC HMI IPC577C Operating Instructions Manual

Note
When the system is set to automatically adjust the clock for daylight saving time adjustment,
systems without central time management and with activated EWF set the clock forward or
backward by one hour in the daylight saving time or standard time period each time the
system boots.
The reason for this behavior is that Windows Embedded Standard 2009 or Windows
Embedded Standard 7 has a registry entry that detects the conversion to daylight saving
time. Since this file is also protected against modification by the EWF, the marker is lost
during the boot sequence and the adjustment is made again.
We therefore recommend that you deactivate the automatic adjustment and change the
clock manually.
Procedure:
1. Switch off the EWF filter (ewfmgr c: -commitanddisable) and reboot the system.
2. Deactivate automatic adjustment in the Control Panel. Select Start > Control Panel >
3. Enable EWF again (ewfmgr c: -enable) and reboot the system.
10.5

File Based Write Filter (FBWF)

Purpose and function
With the Feature Pack 2007 for Windows XP Embedded, Microsoft introduced a second
write filter, File Based Write Filter (FBWF).
In contrast to EWF, which protects partitions based on sectors, FBWF works on the file level.
When FBWF is enabled, all files and folders of a partition are protected unless they are
included in an exception list.
FBWF is disabled by factory default in the operating system images for SIMATIC IPC and
must be enabled and configured by the user.
When you enable FBWF, the folders C:\FBWF and D:\FBWF are authorized for writing by
default.
CAUTION
Activate only one write filter per partition - otherwise you may incur data loss.
Both EWF and FBWF are preinstalled in the SIMATIC IPC images.
Ensure that only one write filter is enabled on a partition, otherwise you may incur data loss.
SIMATIC HMI IPC577C
Operating Instructions, 10/2010, A5E02368074-02
Date and Time > Time Zone tab to clear the check mark from the "Automatically adjust
clock for daylight saving changes" check box.
10.5 File Based Write Filter (FBWF)
Functions
85