Omron NSA, Manual

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Appendix 2 Using the Enhanced Write Filter
Appendix 2-1 About the EWF Function
Appendix-21
Appendix
Appendix
Appendix 2 Using the Enhanced Write
Filter
This section describes the use of the Enhanced Write Filter (EWF) for increasing the reliability of the
NSA-series Industrial PC.
Appendix 2-1 About the EWF Function
To protect the OS and application software stored in the DiskOnModule (DOM)
storage drive of the NSA-series Industrial PC, it is possible to prohibit the writing
of data to the DOM. This is done by using the Enhanced Write Filter of the
Windows XP Embedded OS. By using this function, any data that is to be written
from the OS or application software is emulated in the main memory, so it appears
to the user that the data is written or settings are changed in the same manner as
in ordinary Windows operation, but in reality all data and settings changes are
deleted each time Windows is restarted or the power is turned OFF.
The EWF function is disabled when the NSA-series Industrial PC is shipped from
the factory. To use the EWF function, you must enable it (see Appendix 2-3).
When the EWF function is enabled and it is necessary to update data on the
DOM due to settings changes or file updates, the updated content can be
reflected as described in Appendix 2-4. Another way to do this is to disable the
EWF function and update the data to the DOM directly, as described in Appendix
2-5. When any change is made to the EWF function, the Unit must be restarted for
the change to take effect.
Appendix 2-2 Confirming the Operating State of the EWF Function
Display the command prompt screen, then input the following command to confirm
the operating state of the EWF function.
Command: ewfmgr c:
Execution Example
Definition: State
Displays the operating state of the EWF function.
ENABLED – Indicates that the EWF function is enabled. The function will
emulate writing data to the DOM.
DISABLED – Indicates that the EWF function is disabled. Data will be
directly written to the DOM.