Using The Unified Write Filter (Uwf) - NEC Express5800 Series User Manual

Chapter 5 Administrative Utilities and Settings
3.

Using the Unified Write Filter (UWF)

The Unified Writer Filter provides a secure environment for thin-client computing by protecting the thin client from
undesired flash memory writes (flash memory is where the operating system and functional software components reside).
By preventing excessive flash write activity, the Unified Writer Filter also extends the life of the thin client. It gives the
appearance of read-write access to the flash memory by employing an overlay to intercept all flash writes and returning
success to the process that requested the I/O.
Protected and cached flash memory contents can be used while the thin client is active, but they are lost when the thin
client is restarted or shut down. To preserve selected changes, disable UWF in the Atrust Client Setup dialog box, change
the settings, and then enable UWF again. (See Chapter 4, "2.9 Configuring UWF (Unified Write Filter)".) The Unified Writer
Filter can be enabled and disabled by using the command line (uwfmgr). The Unified Writer Filter can commit (write) the
specified files to the flash memory from the overlay. (If more changes are made on files that have been committed, these
files must be committed again if the changes also need to be preserved.) The enabled/disabled status of the Unified Writer
Filter is indicated by the Unified Writer Filter status icon in the system tray. Green indicates that the Unified Writer Filter
is enabled, red indicates that the Unified Writer Filter is disabled, and orange indicates that the status has been changed
and will be applied at the next restart.)
Important The administrator should periodically check the status of the UWF overlay and restart the thin
client if the UWF overlay is more than 80% full.
Do not write data exceeding the maximum size of the UWF overlay, as this will make the thin
client unstable.
Remote Desktop Services Client Access License (RDS CAL) is always preserved, regardless of whether
Tip
it is added to the exceptions list of the UWF
Express5800/US320f User's Guide
3. Using the Unified Write Filter (UWF)
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