Features In Windows Embedded; Enhanced Write Filter (Ewf) - Advantech TPC 51T 3BE Series User Manual

3.1

Features in Windows Embedded

TPC supports an embedded Windows platform. This section outlines the important
features (EWF, FBWF and HORM), that are provided in WES7 and UWF provided in
WE8S.
3.2

Enhanced Write Filter (EWF)

Enhanced Write Filter (EWF) and File-Based Write Filter (FBWF) redirect all writes
targeted at protected volumes to a RAM or disk cache, called an overlay. The overlay
stores changes made to the operating system, but is removed when the device is
restarted, restoring the device to its original state. Note that there is no disk-based
overlay support for Windows Embedded Standard 7.
EWF works at the sector level on protected disks and allows you to commit changes
so that they persist when the device is restarted. EWF is useful for thin clients that do
not need to store cached information or receive frequent updates. Changes made to
a system protected by EWF are stored in one or more layers that represent snap-
shots in time. Applying changes to an image applies all changes made to the operat-
ing system during a specific period of time.
Advantech provides a utility to operate EWF. To enable this utility, follow the steps
below:
Click Start Menu->All Programs->Advantech->AdvWF and click EWF Utility
1.
2. Click the EWF tab, and click Enable button
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