Windows operating systems

EWF (Enhanced Write Filter)

The EWF (Enhanced Write Filter) protects the entire partition from write accesses without exceptions. If the EWF is active, all write accesses are redirected to the RAM. Following a restart or a power failure, the system is returned to its original state.

The EWF is controlled by the Beckhoff EWF Manager software, which is already installed by default.

Beckhoff EWF Manager, user interface.
 
Key to Beckhoff EWF Manager.
No.
Description
1
Switch EWF on, switch EWF off.
2
Data can be accepted at runtime if the EWF is active.
3
Switch EWF off without a restart.
4
Reset boot command to NO COMMAND.
5
Name of the partition.
6
ID of the partition on which the EWF is executed (in hexadecimal).
7
Indicates which commands are executed after the restart. The following commands exist:
NO COMMAND, no changes.
ENABLE, the EWF is switched on after the restart.
DISABLE, the EWF is switched off after the restart.
COMMIT, data are written to the storage medium when shutting down, even though the EWF is switched on.
8
Indicates the current status, i.e. whether the EWF is switched on or switched off.
9
Indicates the EWF mode. In RAM REG mode, all accesses are redirected to the RAM and the EWF settings are stored in the Registry.

Requirements:

Windows Embedded Standard 2009 or
Windows Embedded Standard 7 P

Activate the EWF as follows:

1.
Start the Industrial PC or Embedded PC and click Beckhoff EWF Manager under Start < All Programs < Beckhoff EWF Manager.
2.
Under Action, click the Enable EWF button.
3.
Confirm the settings so that the changes become effective.
The changes are only active after a restart. You have successfully activated the EWF.