Siemens IPC427C manual Enhanced Write Filter EWF, Purpose and function, Set EWF, Function Command

Functions

9.2 Enhanced Write Filter (EWF)

9.2Enhanced Write Filter (EWF)

Purpose and function

The EWF (Enhanced Write Filter) is a function that is only available with Windows Embedded operating systems. It provides write protection that can be configured by the user.

The Enhanced Write Filter allows you to boot Windows Embedded Standard 2009 from write-protected media (such as CD-ROM), to write protect individual partitions and adapt the performance of the file system to your needs (when using CompactFlash cards, for example).

EWF can be used to minimize write access to Compact Flash cards. This is important because the write cycles on Compact Flash cards are limited due to technical reasons. We therefore recommend using EWF if you work with Compact Flash cards.

CAUTION

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.

Note

The Enhanced Write Filter is disabled by default for Windows Embedded Standard 2009. After the operating system has been set up, you should back up your date and then enable the EWF.

Set EWF

The EWFMGR.EXE program can be used to install, enable or disable the EWF. Use the command prompt to call up the program. The following functions are available:

Function	Command
Write-protect drive C: Switching on	ewfmgr c: -enable
Write-protect drive C: disable	ewfmgr c: -commitanddisable
(modified files are accepted)
Modified files on drive C: Accept	ewfmgr c: -commit
Display information about the EWF drive	ewfmgr c:
Display help	ewfmgr c: /h

Note

The EWF commands affecting the write protection do not become active until after the next booting process.

48	SIMATIC IPC427C
	Operating Instructions, 04/2009, A5E02414743-01