The File Based Write Filter provides a secure environment
for thin clientOptiplex client computing by protecting
the thin clientOptiplex 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 File Based Write Filter also extends the life of the thin clientOptiplex client. It gives the appearance
of read-write access to the flash by employing a cache to intercept
all flash writes and returning success to the process that requested
the I/O.
The intercepted flash writes stored in cache are available
as long as the thin clientOptiplex client remains active but
are lost when the thin clientOptiplex client is restarted or
switched off. To preserve selected changes, the selected files of
the cache can be transferred to the flash manually using Commit in
the File Based Write Filter Control dialog box; alternatively,
if the files affected by the changes are not known, the changes can
be made after disabling the File Based Write Filter using the File
Based Write Filter Control dialog box, and then re-enabling the
File Based Write Filter, For more information, see Setting the File
Based Write Filter Controls.
The File Based Write Filter can be controlled either
through the command line (fbwfmgr) or by double-clicking the File
Based Write Filter icon in the Administrator system tray. The File
Based Write Filter can flush specified files to the flash from cache
only up to the point when the commit is performed; if more writes
are performed on the files that have been flushed, then these files
must be flushed/committed again if the additional changes also need
to be preserved.
The File Based Write Filter can also be enabled/disabled
through the command line or through the File Based Write Filter Enable/Disable
desktop icons. The status (enabled/disabled) of the File Based Write
Filter is displayed by the File Based Write Filter status icon in
the system tray green indicates that the File Based Write Filter is
enabled and red indicates that the File Based Write Filter is disabled.
NOTE:
Contents of the File Based Write Filter cache should
never be flushed if it is eighty-percent or more full. The Administrator
should periodically check the status of the cache and restart the thin clientOptiplex client if the cache is
more than eighty percent full. Note that alternatively an administrator
can configure the client to reboot if the FBWF cache is 90 percent
or more full. By default the client is configured to reboot if the
FBWF cache usage exceeds 90 percent.
A Terminal Services Client Access
License (TSCAL) is always preserved regardless of File Based Write
Filter state (enabled or disabled). If you want to have other registry
settings preserved regardless of File Based Write Filter state, contact
support for help as described in Technical Support.
WARNING:It is highly recommended that Windows write filter
is kept enabled during normal use of thin clients. It should be disabled
only by administrators while making necessary changes. Extended use
with write filters turned off can reduce the life of your flash drive.
It is a good practice to have write filters enabled to ensure device
security.
This section provides the following information on
using the File Based Write Filter: