Features Of Windows Embedded Os; Enhanced Write Filter (Ewf) - Advantech TPC-5212W-633AE User Manual

3.1

Features of Windows Embedded OS

The TPC series systems support the embedded Windows OS platform. This chapter
outlines the important features (EWF, FBWF, UWF, and HORM) that are provided in
WES7.
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, which is known as an overlay.
Although the overlay stores any changes made to the operating system, it is deleted
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 users to implement
changes that 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 run EWF. Follow the steps outlined below to enable
this function.
1. Access Start Menu->All Programs->Advantech-> AdvWF and then click EWF
Utility.
TPC-5000 Series User Manual 24