Operating the device and device functions
5.5 Extended device functions
SIMATIC IPC477E
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Operating Instructions, 11/2020, A5E37455003-AF
5.5.4
File Based Write Filter (FBWF)
Purpose and function
With the Feature Pack 2007 for Windows XP Embedded Standard 7, 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.
Comparison between EWF and FBWF
•
You should prefer FBWF, because it is more flexible in its configuration and allows
immediate writing without rebooting.
•
If you use HORM or compressed NTFS, EWF is indispensable.
CAUTION
Data loss with several write filters
Both EWF and FBWF are preinstalled in the SIMATIC IPC images. If several writer filters
are active on one partition at the same time, you may experience data loss. This may
damage the machine or plant.
Make sure that you only activate one write filter for each partition.
Configuring FBWF
FBWF can be configured in command console using the program FBWFMGR.EXE.
Note
•
Observe the following syntax: Enter a
space
after the drive designation colon.
•
Changes for direct write access only take effect after rebooting.
•
Only existing files and folders can be entered in the exception list.
