HP MP6 Base Model Write filters, Choosing the write filter, Enhanced Write Filter Manager

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Write filters

Choosing the write filter

HP Windows Embedded Standard digital signage players include both the Enhanced Write Filter (EWF) and the File-based Write Filter (FBWF) to protect the operating system.

The writer filter is disabled by default.

TIP: Choose the Enhanced Write Filter to protect an entire partition from writes, or choose the File- based Write Filter to allow specific local applications and files to be updated dynamically.

To select the EWF or FBWF, perform the following steps:

1.Log on as an Administrator.

2.Select Start > Control Panel > HP Write Filter Configuration.

3.Select and configure the desired write filter.

4.Reboot the system for the chosen write filter selection and configuration to take effect.

Enhanced Write Filter Manager

WES includes the Enhanced Write Filter (EWF) console application command-line tool, ewfmgr.exe. In addition to the DOS command-line tool, the WES image includes an Enhanced Write Filter GUI. The EWF allows the operating system (OS) to boot from a disk volume residing on any read-only media or write-protected hard drive while appearing to have read/write access to the OS. The EWF saves all writes to another storage location called an overlay. Changes made to the overlay will not be committed to the flash memory or hard drive unless the EWF has been disabled or the user performs an intentional commit.

The EWF manager console application can be used to issue a set of commands to the EWF driver, report the status of each protected volume overlay, and report the format of the overall EWF configurations.

By including the EWF manager console application component in the configuration and building it into the run-time image, you enable the use of ewfmgr.exe and the corresponding commands.

Benefits of the Enhanced Write Filter

The EWF provides a secure environment for digital signage player computing. It does this by protecting the digital signage player from undesired writes. For the MP4 unit, the write filter also extends the life of the digital signage player 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 stored in cache are available as long as the digital signage player remains active, but they will be lost when the digital signage player is rebooted or shut down. To preserve the results of writes to the registry, the contents of the cache can be transferred to the flash on demand or manually using the Enhanced Write Filter Manager.

After the write filter has been disabled, all future writes during the current boot session are written to the storage device, with no further caching until a reboot occurs. The write filter may also be enabled/ disabled through the command line. Always enable the writer filter after all of the permanent changes have been successfully made.

16 Chapter 5 Control panel extended selections

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Contents Quick Reference Guide Copyright 2013 Hewlett-Packard Development Company, L.P About this book Iv About this book Table of contents HP Digital Signage Player Imaging Tool For more information and updates HP updates For more informationDesktop IntroductionUser desktop Administrator desktop Automatic logon ConfigurationLogging on Press and click Start Shut Down Log OffAdministrator logon access Manual logonSystem date and time Write filtersClick Start Shut Down Click Change Settings Drive C and flash Local drivesUser accounts Creating a new user accountUser profiles User Accounts utilityClick Control Panel User Accounts Manage Another Account Regional and language options Select Create a New AccountClick the Administrative Tools icon in the Control Panel Administrative toolsWireless network configuration Manually Create a Network or Create an AdHoc NetworkRemote Desktop Connection RDC ApplicationsWindows Firewall Select Control Panel Windows FirewallRight-clickWindows Internet Explorer 9, and click Uninstall Open Control Panel Programs and FeaturesMicrosoft Internet Explorer Page Control panel extended selections Choosing the write filter Select Start Control Panel HP Write Filter ConfigurationWrite filters Enhanced Write Filter ManagerEnhanced Write Filter status service Enhanced Write Filter GUI EWF GUI ButtonsFile-Based Write Filter Manager DOS command-line tool boot commandsBenefits of the File-Based Write Filter File-Based Write Filter Status Service File-Based Write Filter GUI Control panel extended selections Administration and image upgrades HP Digital Signage Player Imaging ToolIndex Accounts
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