Enhanced Write Filter Manager

The Enhanced Write Filter Manager provides a secure environment for thin-client computing by protecting the thin client from undesired flash memory writes (the operating system and functional software components reside in flash memory). The write filter also extends the life of the thin client by preventing excessive flash write activity. 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 that are stored in cache are available as long as the thin client remains active, but are lost when you reboot or shut down the unit. To preserve the results of writes to the registry, favorites, cookies, and so forth, you can transfer the contents of the cache to the flash on demand using the Altiris Deployment Solution software or manually using the Enhanced Write Filter Manager.

After you disable the write filter, all future writes during the current boot session are written to the flash with no further caching until reboot. You can also enable/disable the write filter using the command line. Always enable the writer filter after you have made all of your permanent changes.

The administrator should periodically check the status of the cache and reboot the thin client if the cache is more than 80 percent full.

ÄCAUTION: Never disable the write filter cache if it is more than 80 percent full.

✎To avoid flash corruption when administering the thin client for permanent changes, HP strongly recommends that you disable the write filter cache before making permanent modifications to the system. Remember to enable the writer filter after making all of your changes.

The following section describes how you can manipute the write filter through the command line.

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