Operating the device and device functions
5.5 Extended device functions
SIMATIC IPC477E
Operating Instructions, 11/2020, A5E37455003-AF
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5.5.2
Unified Write Filter (UWF)
The Unified Write Filter
is a configurable write filter that makes it possible to assign write-
protection to data storage media, such as hard disks, CFast cards, SSDs, internal USB drives,
or external SATA drives.
External removable data storage media such as USB sticks and other flash drives, which are
recognized by the operating system as a removable data storage medium, are not supported.
UWF combines the advantages of older write filters such as EWF and FBWF. It prevents all
write access to protected media and transfers the data to buffer memory (overlay). This
increases the reliability and stability of the system as well as the service life of write-sensitive
media such as SSDs and CFast cards.
Note
UWF is disabled in the delivery state.
Note that memory is reduced when UWF is enabled.
NOTICE
Risk of data loss with enabled UWF
When UWF is enabled, all changes made to storage media with a UWF write protection after
booting can be lost when the device is shut down. Proceed as follows to prevent this
situation:
•
Make changes to storage media only when UWF is disabled.