Advanced device functions
5.2 Enhanced Write Filter
Enhanced Write Filter
Purpose and function
The EWF (Enhanced Write Filter) is a function that is only available for Windows Embedded
operating systems. It provides write protection that can be configured by the user.
The Enhanced Write Filter enables you to boot Windows Embedded Standard from read-
only media (e.g. CD-ROM), assign write protection attributes to partitions, and customize file
system performance (when using CompactFlash cards, for example).
EWF can be used to minimize write access to CompactFlash cards. This is important
because the write cycles on CompactFlash cards are limited due to technical reasons. We
therefore recommend using EWF if you work with CompactFlash cards.
Activate only one write filter per partition - otherwise you may incur data loss.
Both EWF and FBWF are preinstalled in the SIMATIC IPC images.
Ensure that only one write filter is enabled on a partition, otherwise you may incur data loss.
In Windows Embedded Standard, the Enhanced Write Filter is disabled by default. After the
operating system has been set up, you should back up your date and then enable the EWF.
The following programs can be used to install, enable or disable the EWF:
● SIMATIC IPC EWF Manager
The SIMATIC IPC EWF Manager is preinstalled and included on the supplied
"Documentation and Drivers" CD/DVD. The SIMATIC EWF Manager can be started with an
icon in the system tray on the task bar.
EWFMGR.EXE is started with the command prompt. The following functions are available:
Write-protect drive C: Switching on
Write-protect drive C: disable
(modified files are accepted)
Modified files on drive C: Accept
Display information about the EWF drive
ewfmgr c: -enable
ewfmgr c: -commitanddisable
ewfmgr c: -commit
ewfmgr c: /h
Operating Instructions, 12/2016, A5E03409486-AE