Lenze IPC Operating System Windows Embedded-XP - Handbuch (Seite 26)

Configuration
Activation and Deactivation of the LDC Write Filter Manager
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26 LDCDP−12549 DE/EN 3.0
3 Configuration
3.1 Activation and Deactivation of the LDC Write Filter Manager
Starting with Feature Pack 2007 Windows XP Embedded supports two different kinds of
write protection:
ƒ File Based Write Filter (EBWF) which works on file level
ƒ Enhanced Write Filter (EWF) which works on disk sector level.
The Enhanced Write Filter (EWF) protects whole data media or partitions against writing.
Every write access on an EWF protected partition is sent to an overlay in the random access
memory (RAM) that is cleared after a restart.
One possibility to make changes to files or registry entries is to deactivate the Enhanced
Write Filter. After that, the changes are made and the Enhanced Write Filter is reactivated.
The second possibility is to store the changes during the current session.
The File Based Write Filter" (FBWF) uses another approach which is protection on the file
level instead of protecting a whole data medium or partition, respectively, like the
Enhanced Write Filter does. The user can classify certain files or folders as unprotected. All
write accesses to a protected object are cleared in the next session. Write accesses to
unprotected objects are stored and remain available until the next session.
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Note!
ƒ Administrator rights are needed to change the Write Filter Configuration.
ƒ Only one of the write protections (EWF or FBWF) can be active at a time.
ƒ If EWF is active, make sure that, in general, there is no writing from the
software applications on the system partition. This is the only way to
impede an overflow in the random access memory (RAM).
Setup of the Enhanced Write Filter (EWF)
1. Start LDC Write Filter Manager (<Start>
à Control Panel à LDC Write Filter
Manager).
2. Activate the registryEnhanced Write Filter (EWF) .
– Enable EWF (only available if EWF is deactivated): Activates EWF. After activating
the EWF, a restart is required. System partition "C:" is protected after the restart.
– Save Changes (only available if EWF is activated): All data and changes of this
session are stored.
– Disable Write Filter (only available if EWF is activated): Deactivates EWF. After
deactivating the EWF, a restart is required. EWF protection is suspended.