Valueline EWF Administrator Utility
Contents
1. 2 1 5 EWF effects on system testing A system that uses EWF must be thoroughly tested with EWF protection enabled to confirm that the EWF cache space consumed leaves sufficient RAM available for normal application and operating system operation the EWF cache space does not consume RAM at an unacceptable rate 2 2 EWF management options Microsoft provides two tools for EWF status and control EWF Manager This is a command line tool EWFMGR EXE that provides all of the EWF commands disable enable commit etc EWF Management This is a Windows GUI tool EWFMgmt exe providing a graphical interface for most of the EWF commands EWF Manager Commands http msdn microsoft com en us library ms940853 v WinEmbedded 5 aspx New features are now available for Embedded Standard 2009 operating system http blogs msdn com b embedded archive 2011 05 27 new features are now available for standard 2009 aspx PHOENIX CONTACT 2 3 3014_en_A EWF 2 4 PHOENIX CONTACT Phoenix Contact provides the Valueline EWF Administrator utility EWFAdmin exe for EWF status and control and additional EWF monitoring and analysis features see Valueline EWF Administrator on page 3 1 2 3 EWF cache space exhaustion EWF is a powerful and very effective feature but has one important limitation the possibility of exhaustion of space available for the EWF cache which often results in application crashes or lockup T2. or Commit amp Disable Live In the case of a Shutdown or Restart automatic action the logfile will not persist after the next reboot as it will not be written to the disk due to the EWF feature It is recommended that the logfile directory be set to a writable non protected volume such as an additional non protected partition on the primary CompactFlash card asecond CompactFlash card a USB flash drive inthe case of a VL BPC MINI the SecureDigital memory card Maximize System Pages Click the Maximize System Pages button to apply a Windows registry setting to maximize system pages that effectively increases the amount of EWF cache space by about 180 200 MB This is a one time operation and the button is disabled afterwards The Maximize System Pages button is enabled only on Windows Embedded Standard 2009 and is disabled on Windows Embedded Standard 7 A coniirmation dialog box is displayed Valueline EWF Administrator x 7 This operation will modify the Windows SystemPages value in the registry to maximize the available system page r table entries For EWF cache usage After setting SystemPages a Commit and automatic system reboot will occur Do you want to continue with this operation Figure 3 19 Maximize System Pages confirmation message Click the Yes button to apply the registry change An automatic EWF Commit operation and system reboot also
3. User manual UM EN Valueline EWF Administrator Utility Simplified management and diagnostics of enhanced write filter functions for Microsoft Windows Embedded Standard operating systems OGD 0 7 06B e 1 INSPIRING INNOVATIONS User manual Simplified management and diagnostics of enhanced write filter functions for Microsoft Windows Embedded Standard operating systems 2012 03 26 Designation UM EN Valueline EWF Administrator Utility Revision A This user manual is valid for Designation Version Valueline IPCs configured with an Embedded Standard OS Valueline EWF Administrator Utility 1 0 3014_en_A PHOENIX CONTACT Internet Subsidiaries Published by Please observe the following notes User group of this manual The use of products described in this manual is oriented exclusively to qualified application programmers and software engineers who are familiar with the safety concepts of automa tion technology and applicable standards Explanation of symbols used and signal words hazards Obey all safety measures that follow this symbol to avoid possible in This is the safety alert symbol It is used to alert you to potential personal injury jury or death There are three different categories of personal injury that are indicated with a signal word DANGER This indicates a hazardous situation which if not avoided will re sult in death or serious injury WARNING This indicates a
4. Valueline EWF Administrator dialog box on page 3 3 To manually terminate the Valueline EWF Administrator application right click the icon and click the Exit option see Program Exit on page 3 8 The Valueline EWF Administrator dialog box consists of the following groups 3 4 2 1 EWF Status The EWF Status group displays information about the current EWF protection Protected volume Displays the drive name of the current EWF protected volume for example C Mode Displays the EWF protection mode For example RAM Reg which is the only mode supported by Valueline EWF Administrator Current state Displays current EWF protection state either Disabled or Enabled Pending command Displays the pending EWF boot command as manually requested by the operator via the Valueline EWF Administrator or Microsoft manager tools EWFMGR exe or EWFMGMT exe The valid values are NONE no EWF command is pending this is the default value DISABLE the EWF DISABLE command has been requested ENABLE the EWF ENABLE command has been requested COMMIT the EWF COMMIT command has been requested 3 4 2 2 EWF Commands group Disable Enable EWF button Click the Disable EWP button to disable EWF at the next system shutdown restart as indicated in a confirmation message EWF Status Memory Usage Protected volume C Valueline EWF Administrator Mode RA e 4 Disabl
5. wizard and Settings dialog box Low memory threshold This field displays the current value for the low memory threshold in megabytes When either the available physical memory or available page table memory drop below this threshold a preselected action will be taken so that in the absence of an operator exhaustion of the available EWF cache space can be automatically avoided The value may be modified by the user in the Settings dialog box The low memory threshold is checked every five seconds the default refresh interval which may also be configured by the user in the Settings dialog box PHOENIX CONTACT 3 7 EWF Threshold action This field displays the preselected action to be taken upon available memory dropping below the low memory threshold above while EWF is enabled It has no effect when EWF is disabled The available actions taken upon reaching the low memory threshold are None no automatic action Restart the system is automatically restarted Shutdown the system is automatically shut down Commit amp Restart the EWF cache is automatically committed to disk during the system shutdown followed by a system restart Commit amp Disable Live the EWF cache is committed live to disk without shutting down or restarting the system The EWF feature is left in a disabled state External Event a Windows software event is set to be detected by external software No other
6. 3 5 3 FOJOW UD Warning EE 3 20 A MECNNICaLADDENADC E A 1 A1 External Event Application Program Interface aaa zana aaa aaaaaacc A 1 SE ele nelle B 1 B 1 Be t elt B 1 3014_en_A PHOENIX CONTACT i EWF il PHOENIX CONTACT 3014 en A 1 Introduction 3014_en_A Introduction Enhanced Write Filter EWF is a component of Microsoft Windows Embedded Standard operating systems that filters writes to a physical volume caching them to another medium instead of being physically writing them to the volume itself As this minimizes writes to a specified physical volume EWF is an effective way to decrease wear on CompactFlash and solid state hard drive SSHD volumes when the changes to the volume don t need to be available after a reboot When the EWF cache medium is memory the most common failure mode of EWF is exhaustion of space available for the EWF cache which often results in application crashes or lockup This may occur after days or weeks of continuous operation of an embedded application and is a fundamental limitation in the implementation of the EWF component As a recommended solution to this problem the Valueline EWF Administrator utility is presented The Valueline EWF Administrator simplifies the management of EWF and provides the ability to analyze the EWF usage of an application and safeguard against out of memory failures that may occur over extended operation 1 Additional information on the Enhanced Write Filter c
7. EWF or system actions are taken in this case The threshold action may be configured in the Settings dialog box Analyze button This button launches the EWF usage analysis wizard see Analyze wizard on page 3 9 Settings button This button launches the Settings dialog box see Settings on page 3 14 3 4 3 Tray icon When Valueline EWF Administrator is launched it inserts an icon in the notification area of the taskbar Double click the icon to hide or display the Valueline EWF Administrator dialog box depending on the current state of display Alternatively right click the icon to display amenu allowing selection of either Hide or Display depending on the current state of display 3 4 3 1 Program Exit To exit the Valueline EWF Administrator right click the icon and click the Exit option Two warning messages may be displayed fan EWF command is pending a warning message displays asking to restart the operating system CR You must restart Windows for the pending EWF command to take ER effect Restart now pe Je Figure 3 9 Pending EWF command warning message 3 8 PHOENIX CONTACT 3014_en_A Valueline EWF Administrator Ifan automatic threshold action is configured i e if the threshold action is something other than None a warning message displays asking to verify the exit command Are you sure you want to exit Figure 3 1
8. Global Valueline EWFAdmin ThresholdEvent if feet null i Console Write Failed to create event wait handle return if evt WaitOne Console Write Detected Valueline EWFAdmin ThresholdEvent return Figure A 2 C sample code A 2 PHOENIX CONTACT 3014 en A B Appendices 3014 en A B 1 Figure 2 1 Figure 2 2 Figure 3 1 Figure 3 2 Figure 3 3 Figure 3 4 Figure 3 5 Figure 3 6 Figure 3 7 Figure 3 8 Figure 3 9 Figure 3 10 Figure 3 11 Figure 3 12 Figure 3 13 Figure 3 14 Figure 3 15 Figure 3 16 Figure 3 17 Figure 3 18 Figure 3 19 Figure 3 20 Figure 3 21 Figure 3 22 Figure 3 23 Figure 3 24 List of figures EWF enabled RAM or RAM Reg mode aauueaaaaanssca naa 2 2 EWF Commit RAM or RAM Reg model nennen 2 2 Splash SCIOCM wadia dawalo REG KOR o EE 3 3 Valueline EWF Administrator dialog box e aauueaaaaae aaa caanai 3 3 Disable EWF confirmation message s aauuu aaa aaaaananscaace 3 4 Valueline EWF Administrator dialog box with EWF disabled 3 5 C ommiiedialog DOE dada e AGP wt EWA 3 5 Commit reboot message box AANEREN 3 6 Valueline EWF Administrator dialog box with Commit pending 3 6 CommitAndDisableLive message box eesaaaaaaaaa aaa aaaaannai 3 7 Pending EWF command warning message sseaaanuua0 3 8 Pending EWF exi
9. occurs Allocate Volume Space The Allocate Volume Space feature provides another way to help avoid EWF cache space exhaustion analogous to the method Partition system volume on page 2 4 Large files are allocated on the protected volume leaving it with a much smaller amount of free space The reduced free disk space now becomes the limiting factor for future system operation such that the embedded application and operator may eventually receive warnings and errors regarding out of disk space from the Windows operating system before or instead of encountering failures due to EWF cache space exhaustion Click the Allocate Volume Space button to activate this feature 3014_en_A 3014_en_A Valueline EWF Administrator If EWF protection is enabled when the Allocate Volume Space button is clicked a message box notifies the user that EWF must first be disabled i h This feature requires that EWF protection is disabled which will require F a reboot Do you want to continue Figure 3 20 Allocate Volume Space and EWF proteciion conilict message box Click the Yes button to automatically disable EWF protection and restart the operating system Upon restart the operator may again open the Settings dialog box and click the Allocate Volume Space button If EWF protection is disabled a confirmation message appears MDF feature will allocate 1044 MB of the existing 1626 MB of space o
10. to launch the Commit dialog box Valueline EWF Administrator Commit gt Please choose type of Commit desired Commit amp Disable LIVE Commits EWF cache to disk immediately without requiring reboot but leaves EWF protection disabled Figure 3 5 Commit dialog box Two radio buttons allow selection of the Commit method Commit May be selected for a normal EWF Commit operation which commits the EWF cache to disk upon shutdown and restart This is the default option PHOENIX CONTACT 3 5 EWF With this radio button selected click the OK button and the EWF Commit command is launched during the next system shutdown restart EWF Status Memory Usage Protected volume C Valueline EWF Administrator jet juse 15 MB Mode RA ory 1571 MB Commit requested successfully jemory 1417 MB EWF Commands Please reboot for this command to take effect Disable EWF 100 MB Commit amp Restart Figure 3 6 Commit reboot message box The Commit command will only take effect after the next system shutdown restart operation The user will be reminded to perform a restart when closing the dialog box Click the OK button to close the message box The EWF Status group will indicate the current and pending commands EWF Status Memory Usage Protected volume C Current state ENABLED EWF cache memory in use 11 MB Mode RAM Reg Pending command COMMIT Available physical memor
11. 0 Pending EWF exit warning message 3 4 4 Analyze wizard The EWF Usage wizard provides the ability to measure and analyze the EWF usage while operating the target Windows Embedded application The analysis consists of four steps Step 1 Pre test The current protected volume and memory conditions are reported Step 2 Test The wizard monitors the system while the user exercises the system Step 3 Post test The wizard shows a summary of protected volume and memory usage along with an estimate of EWF cache space exhaustion Step 4 Final The wizard provides recommendations to maximize EWF cache space and configure Valueline EWF Administrator to detect and handle low space conditions Analyze EWF Usage This feature provides the ability to measure and analyze EWF usage on the current PC Upon completion recommended settings will be provided to maximize EWF usage To continue dick Next Figure 3 11 Valueline EWF Administrator Analyze wizard 3014 en A PHOENIX CONTACT 3 9 EWF 3 4 4 1 Step 1 The Step 1 dialog box displays the current RAM and disk information along with a preliminary assessment of the potential limiting factor of EWF cache space Current Vital Statistics Total size Available space Protected volume C 3886 MB 1764 MB Physical memory 2038 MB 1544 MB System page table memory 1669 MB 1422 MB Preliminary assessment EWF cache will be limited primarily by the system pa
12. EWF Administrator as well as configuration of the PC itself Valueline EWF Administrator Settings x Threshold Options Low memory threshold DAN MB Action override interval 30 seconds Threshold action e None C Restart C Shutdown C Commit amp Restart C Commit amp Disable Live External Event Program Options Refresh interval D seconds Loofile directory CHEWFAdminLogs a System Configuration Options Maximize System Pages Allocate volume Space cze Figure 3 17 Settings dialog box After making the desired changes click the OK button to save the settings in a file named EWFAdmin ini located in the same directory as the program executable file If this directory is located on the protected volume and EWF is currently enabled a confirmation message appears Valueline EWF Administrator In order bo commit the changed settings to disk a Commit and automatic reboot will occur eh Ss Do you want to continue with this operation Figure 3 18 Confirmation message 3014_en_A Valueline EWF Administrator Click the Yes button and the changed file will be committed to disk via an EWF Commit command and an automatic restart will occur The following settings are available Low memory threshold The low memory threshold controls the Valueline EWF Administrator automatic action feature When either the available physical memory or available page table mem
13. F cache is nearly full This is especially useful when the Valueline EWF Administrator dialog box is hidden The warning message will repeatedly be displayed as long as the available memory is less than 1 5 times the low memory threshold For example if the low memory threshold is 100 MB the warning message will be displayed when available memory is less than 150 MB 1 5 times 100 MB but greater than 100 MB 3 18 PHOENIX CONTACT 3014 en A 3014_en_A Valueline EWF Administrator 3 5 2 Error state EWF Status Memory Usage Threshold for Free Physical Memory has been reached Performing Restart in 26 seconds Restart 63 Valueline EWF Administrator A x EWF cache has exhausted physical memory 59 MB remaining 2 38 PM d ar Er U 7 Pal zm Figure 3 23 EWF cache full error When available physical memory or system page table memory falls below the low memory threshold If the Valueline EWF Administrator dialog box is visible the corresponding memory value is highlighted in red text to draw attention to the error state An error message displays from the tray icon indicating the EWF cache has exhausted available memory This is especially useful when the Valueline EWF Administrator dialog box is hidden An automatic action message with a countdown counter is displayed The counter continues until the action is automatically performed This countdown is configured via the Action overrid
14. aching the threshold This action is taken automatically even if no operator is present If an operator is present the operator has a short period of time to override the automatic action The low memory threshold and threshold action values are displayed in the Valueline EWF Administrator dialog box see EWF Monitoring group on page 3 7 To disable the automatic threshold action set the Threshold Action to None in the Settings dialog box As the available physical memory or system page table memory limits approach several warning states occur that initiate different events 3 5 1 Warning state Memory Usage Protected volume C Current state ENABLED EWF cache memory in use 1332 MB Mode RAM Reg Pending command NONE Available physical memory 160 MB Available page table memory 143 MB EWF Commands EWF Monitoring Disable EWF Clear Command l Low memory threshold 100 MB Threshold action Restart Valueline EWF Administrator EWF cache is nearly full 143 MB remaining en 7 12 2011 a be Peed x Figure 3 22 EWF cache nearly full warning When available physical memory or system page table memory falls below approximately 150 of the low memory threshold Ifthe Valueline EWF Administrator dialog box is visible the corresponding memory value is highlighted in red text to draw attention to the warning state A warning message displays from the tray icon indicating the EW
15. an be found at http msdn microsoft com en us library ms912906 aspx PHOENIX CONTACT 1 1 EWF 1 2 PHOENIX CONTACT 3014_en_A Enhanced Write Filter 2 Enhanced Write Filter 2 1 EWF overview Enhanced Write Filter EWF is a component of Windows Embedded Standard operating systems that filters writes to a physical volume caching them to another medium instead of physically writing to the volume itself EWF allows the writes to be discarded or committed to the physical volume later As this minimizes or even eliminates additional writes to the volume EWF is an effective way to decrease wear on CompactFlash CF volumes which have an inherently limited write cycle lifetime 2 1 1 EWF modes There are three possible modes of EWF operation Note that the mode is preconfigured in the Windows Embedded Standard image and may not be changed later RAM Disk writes are cached in physical RAM and are lost when the machine is shut down or rebooted EWF configuration information is stored on a separate partition called the EWF volume RAM Reg Disk writes are cached in physical RAM and are lost when the machine is shut down or rebooted EWF configuration information is stored in the Windows registry on the protected volume itself Valueline embedded OS images are preconfigured in RAM Reg mode Disk Disk writes are cached in a disk overlay on a separate hard disk which can persist between reboots and provides the possibility to s
16. ave multiple persistent checkpoints of the protected volume 2 1 2 EWF enabled operation When EWF is enabled the EWF component is initialized at the beginning of the boot process so all applications including the Windows OS are prevented from writing to the protected volume at all times For RAM and RAM Reg modes when EWF is enabled it intercepts all disk read and write operations including file creations and deletions by embedded applications drivers and the Windows operating system itself see Figure 2 1 This guarantees that absolutely no write operations will be issued to the EWF protected volume Disk write operations are intercepted and stored in the EWF cache in RAM Disk read operations are satisfied by the protected volume and or the EWF cache 3014 en A PHOENIX CONTACT 2 1 EWF Upon shutdown or restart the contents of the EWF cache in RAM are discarded Disk read write operations by embedded applications drivers and operating system Enhanced write filter Read only Protected volume disk drive CompactFlash s olid state drive Figure 2 1 EWF enabled RAM or RAM Reg mode 2 1 3 EWF commit operation When EWF is enabled if it is desired to save the current state of the system the user may issue an EWF COMMIT request The EWF cache is then written to the protected volume upon the next Windows shutdown or immediately in the case of Commit and Disable LIVE Enhanc
17. d to disk during the system shutdown followed by a system restart Commit amp Disable Live The EWF cache is committed live to disk without shutting down or restarting the system The EWF feature is left in a disabled state External Event A Windows software event is set to be detected by external software No other EWF or system actions are taken in this case Refresh interval The refresh interval determines the frequency of the Valueline EWF Administrator dialog box updates and the low memory threshold checks The allowed range for the refresh interval is 1 second to 60 seconds The default value is 5 seconds 3014 en A PHOENIX CONTACT 3 15 EWF 3 16 PHOENIX CONTACT Logfile directory The logfile directory specifies the location of a log file of critical error conditions and automatic actions taken see Error state on page 3 19 The user may enter any desired directory name in this field on any existing volume or network share The default value is C EWFAdminLogs Use the Browse button to navigate to a desired location If the specified logfile directory does not exist the program will attempt to create it If the logfile directory is blank or if it cannot be created the logfile will not be written If the logfile directory resides on the protected volume e g C the file will only persist if either of the two commit threshold actions are currently selected Commit amp Restart
18. e requested successfully EWF Commands W Please reboot for this command to take effect isane Eve LISGALIE Cw 100 MB Commit amp Restart Figure 3 3 Disable EWF confirmation message 3014 en A 3014_en_A Valueline EWF Administrator Click the OK button to close the message box The EWF Status group will indicate the current and pending commands Memory Usage Protected volume C Current state ENABLED EWF cache memory in use 10 MB Mode RAM Reg Pending command DISABLE Available physical memory 1553 MB Available page table memory 1420 MB EWF Commands EWF Monitoring Low memory threshold 100 MB Threshold action Commit amp Restart zo Figure 3 4 Valueline EWF Administrator dialog box with EWF disabled The Disable and Enable commands will only take effect after the next system shutdown restart operation The user will be reminded to perform a restart when closing the dialog box To cancel a pending command click the Clear Command button Note that this button will change state depending on the current EWF protection state When EWF protection is ENABLED this button is labeled Disable EWF as this is the only valid action while EWF is enabled When EWF protection is DISABLED this button is labeled Enable EWP as this is the only valid action while EWF is disabled Commit button Click the Commit button
19. e application before starting the test Click the Next button to start the test and advance to the Step 2 dialog box 3 10 PHOENIX CONTACT 3014 en A Valueline EWF Administrator 3 4 4 2 Step 2 The Analyze wizard is now monitoring the Windows Embedded system indicated by a constantly moving progress bar see Figure 3 13 The user should run their target application for at least 10 minutes The longer the test the more accurate the analysis EWF Usage Analysis Step 2 Resource monitoring now in progress Please exercise your application for atleast 5 to 10 minutes The longer you exerdse your application the more accurate analysis will be When done exercising your application please dick Next ae CEES e Figure 3 13 EWF Usage Analysis Step 2 dialog box The best results will be obtained if the user runs the target application for at least one full cycle or transaction for cyclical or transaction oriented applications or for a representative sequence of inputs for monitoring oriented applications When satisfied with the length of the application run click the Next button to continue with analysis 3014 en A PHOENIX CONTACT 3 11 EWF 3 4 4 3 Step 3 The Step 3 dialog box displays the overall memory usage results of the test EWF Usage Analysis Step 3 Test duration 00 00 42 HH MM 55 Resource Usage Summary Used during test Usage rate Protected volume C u
20. e interval in the Settings dialog box The default value is 30 seconds Note that this dialog is displayed even when the Valueline EWF Administrator dialog box is hidden The possible outcomes are Ifno action is taken before the countdown reaches zero the preselected automatic action is performed Ifthe operator clicks the OK button the preselected automatic action is performed immediately Ifthe operator clicks the Cancel button the countdown is aborted Note that it will be re displayed again within a short period of time based upon the refresh interval configured in the Settings dialog box This provides the operator time to take some alternate action such as terminating Valueline EWF Administrator to prevent the automatic action from taking place In all cases information is written to the EWF Administrator log file located in the logfile directory specified in the Settings dialog box A single message is logged upon the critical threshold first being met Amessage is logged each time an operator cancels the automatic action PHOENIX CONTACT 3 19 EWF A message is logged when the automatic action is commenced For the External Event action the error message on the tray icon is updated to indicate External event has been set see log This provides confirmation to the user that the event has been set 3 5 3 Follow up warning The next ti
21. ed write filter Protected volume disk drive CompactFlash solid state drive Figure 2 2 EWF Commit RAM or RAM Reg mode 2 2 PHOENIX CONTACT 3014 en A Enhanced Write Filter 2 1 4 EWF effects on system configuration It is important to be aware of EWF status enabled vs disabled when performing configuration functions such as installing or upgrading software on a Windows embedded standard image For example a typical Windows feature installation such as installing a version of the NET framework may unzip hundreds of megabytes of files into a temporary folder on the disk When EWF is enabled all ofthese disk writes will be cached by EWF so when using RAM or RAM Reg mode it is easy to imagine that available space can very quickly be exhausted Therefore the recommended steps for installing or updating large or space consuming software components when EWF protection is enabled are Disable EWF protection Reboot to complete the EWF disable operation Install desired software Configure and test software for normal operation Enable EWF protection Reboot to complete the EWF enable operation Ne 28 19 53 For smaller software feature installations or minor changes to an embedded system configuration the recommended steps when EWF protection is enabled are 1 Install or modify desired software 2 Configure and test software for normal operation 3 Commit EWF cache 4 Reboot to complete the EWF commit operation
22. en_A Valueline EWF Administrator 3 4 4 4 Step 4 The Step 4 dialog box provides detailed information about files created or modified during the test and recommendations for EWF monitoring and configuration based on the test EWF Usage Analysis Step 4 Review File System Access Total number of files modified during test 6 Total cumulative size of modified files 18795946 bytes Recommendations 1 Since the disk volume has a large amount of free space 1764 MB you can get additional protection by reducing the disk free space to a much smaller amount using the Allocate Volume Space function in the Settings dialog 2 The EWF Administrator threshold feature is currently enabled but you may wish to adjust the Threshold value lowering it to reduce premature automatic restarts or increasing it to provide more proactive headroom Click Finish to dose the wizard and open the settings dialog Figure 3 15 EWF Usage Analysis Step 4 dialog box All file system activity during the user s application test in Step 2 is examined and reported in this dialog box Total number of files modified during test This field displays the total number of files created or modified during the user s application test Total cumulative size of modified files This field displays the total size of all created or modified files Note that this is a cumulative total which includes the data pre existing in the files befo
23. eshold Action is set to External Event in the Settings dialog box The memory threshold as set in the Settings dialog box is met i e the free physical RAM or free system page table memory has dropped below the memory threshold A Windows application may detect this named event programmatically by opening the event object and waiting until it is set as illustrated in the sample codes see Sample Code on page A 2 Note that Valueline EWF Administrator will also function correctly if the event object is created and opened by the external application before Valueline EWF Administrator is launched provided the external application uses a compatible security descriptor i e using an access token for the same user account that launches the Valueline EWF Administrator utility The named event object may also be observed for diagnostic purposes using the Sysinternals WinObj tool 3014 en A PHOENIX CONTACT A 1 EWF A 1 2 Sample Code The following are code snippets for C and C HANDLE h CreateEvent NULL TRUE FALSE _T Global Valueline EWFAdmin ThresholdEvent if h printf CreateEvent failed d n GetLastError return DWORD ret WaitForSingle bject h INFINITE if ret WAIT OBJECT 0 d printf Detected Valueline EWFAdmin ThresholdEvent n return Figure A 1 C sample code EventWaitHandle evt new EventWaitHandle false EventResetMode ManualReset
24. fforded legal protection even where they may not be indicated as such Table of contents Re reel Die EE 1 1 2 Gelee VO TEE 2 1 2 1 EWIE EE 2 1 2 1 1 EWF un ee masa e odda att adi idac E 2 1 2 1 2 EWFE enaDled OpOratl m E 2 1 2 1 3 EWF ege lee e te EE 2 2 2 1 4 EWF effects on system configuration u eee a aaaaaa aaa caaaaanci 2 3 2 1 5 EWF effects on system testing ee aeaaeau aaa aaa nana aaa aaaanneci 2 3 2 2 EWF management OpUOnS usa A REEE EES 2 3 2 3 EWF Cache Space exhaustion BEE 2 4 2 3 1 IINECGUSO rss area een 2 4 2 4 EWF cache space exhaustion solutions ssesaaa aaa aaa nenne nennen nennen 2 4 2 4 1 Partition system volume aoc een 2 4 2 4 2 Reduce physical memory EE 2 5 2 4 3 Valueline EWF Administrator cccccccccseeeceeeeeeeeeeeeeseeeeesaeeeeseeeeesaees 2 5 5 Valelne e elle lee EE 3 1 3 1 OWC OW Tera za AE Ee 3 1 3 2 PIELEQUISIIES tee 3 1 3 3 Installallons aa ae ZK EEE C W AD A OK 3 1 3 3 1 Automate start UP 3 1 3 3 2 Alternate ini file location nennen nenn 3 2 3 4 Valueline EWF Administrator Au 3 3 3 4 1 Splash soree eu ui 3 3 3 4 2 Valueline EWF Administrator dialog box us4 44444Bnnn nennen 3 3 3 4 3 VICON ee Z rar lan 3 8 3 4 4 AraNzo e wa enia rk Sa GOO R GERE 3 9 3 4 5 SENGS Zaz Ee ee 3 14 3 5 EWF MoONItOMNJACUHO S aa ek 3 18 3 5 1 E gn Moie EE 3 18 3 5 2 ENO Stal ae ea WA OZ Eco A 3 19
25. ge table entries Begin Test Valueline EWF Administrator can analyze your application s EWF cache usage over a period of time Please complete any setup required to operate your Valueline application before continuing To begin test dick Next Figure 3 12 EWF Usage Analysis Step 1 dialog box Protected volume This field displays the protected volume s drive letter in parenthesis total size and available space rounded to the nearest megabyte MB Physical memory This field displays the physical memory RAM total size and available space rounded to the nearest megabyte MB System page table memory This field displays the total size and available system page table memory space rounded to the nearest megabyte MB System page table memory is usually the primary limiting factor to how large the EWF cache space may grow Preliminary assessment This field displays a short description of the most likely limiting factor for EWF cache space based upon the above vital statistics For example when there is a relatively large amount of free space on the protected volume and in physical memory the system page table memory is usually the limiting factor Begin test This field displays a short explanation of the next step of the Analyze wizard a usage test over a period of time The user should complete any setup steps such as connecting or resetting any external devices accessed or controlled by the Valuelin
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28. his may occur after days or weeks of continuous operation of an embedded application When no more space is available for the EWF cache applications may begin hanging or crashing with little warning since not only are their disk write attempts failing but also drivers and operating system services may begin to hang or crash A common error message in this case is delayed write failure usually shown as a taskbar balloon error message Windows Delayed Write Failed Windows was unable to save all the data for the file C Mft The data has been lost This error may be caused by a failure of your computer hardware or network connection Please try to save this file elsewhere 2 3 1 The cause EWF utilizes physical memory for its cache space in RAM and RAM Reg modes so it Seems logical that the limiting factor for EWF cache would be the available physical memory However configuring the system with additional physical memory may actually reduce the maximum EWF cache size This is due to the fact that the EWF cache utilizes system page table memory which is a relatively small subset of physical memory Therefore in most cases the primary limiting factor for EWF cache size is the amount of free system page table memory Several possible solutions to this problem are discussed in the next section 2 4 EWF cache space exhaustion solutions 2 4 1 Partition system volume Probably the simplest solution to EWF cache space exhaustion i
29. ine EWF Administrator The Valueline EWF Administrator utility see Section 3 Valueline EWF Administrator provides several features to address EWF cache space exhaustion including the ability to monitor the system continuously and automatically take a preselected action as the space available for EWF cache becomes low PHOENIX CONTACT 2 5 EWF 2 6 PHOENIX CONTACT 3014_en_A Valueline EWF Administrator 3 Valueline EWF Administrator 3014_en_A 3 1 Overview Provides graphical user interface for enabling disabling and committing the EWF cache in Windows Embedded Standard 2009 and Windows Embedded Standard 7 operating systems Provides threshold based protection to help avoid failure due to exhausting available space for EWF cache Provides ability to analyze the system while running applications and recommends actions accordingly 3 2 Prerequisites Valueline EWF Administrator requires atleast one EWF protected volume must be configured If none are configured the program reports this and exits If more than one EWF protected volume is configured the program selects the first volume reports this information and continues only RAM Reg mode may be configured on the protected volume If RAM or Disk mode are configured the program reports this and exits 3 3 Installation Simply copy EWFAdmin exe and EWFAdmin ini into an appropriate folder on the target computer If the folder
30. is on a protected volume and EWF is currently enabled you will need to run Valueline EWF Administrator and use the Commit button to commit these changes to disk on the next reboot 3 3 1 Automatic start up To configure Valueline EWF Administrator to start up when a user logs in create a shortcut to EWFAdmin exe in the appropriate Startup folder Then in the Properties tab select the Target field and add the parameter auto The Target field should now look like this if for example the program is installed in the C Tools folder C Tools EWFAdmin exe auto If the Startup folder is on a protected volume and EWF is currently enabled you will need to run Valueline EWF Administrator and use the Commit button to commit these changes to disk on the next reboot Automatic start up is recommended when the automatic EWF monitoring feature of Valueline EWF Administrator is configured PHOENIX CONTACT 3 1 EWF 3 2 PHOENIX CONTACT 3 3 2 Alternate ini file location Valueline EWF Administrator normally expects its settings file EWFAdmin ini to be located in the same directory as the program file EWFAdmin exe which is typically on the EWF protected volume If desired the ini file may be located on another volume using the ini option making it possible to change the settings without the need to commit the EWF cache to disk each time The ini option is fo
31. k the OK button to close the message box To re enable EWF protection repeat the EWF Enable Disable process see EWF Commands group on page 3 4 Clear Command button Click the Clear Command button to clear the pending command as displayed in the EWF Status group This effectively cancels the requested operation after which another EWF command may be issued 3 4 2 3 Memory Usage group The Memory Usage group displays several important physical memory RAM values The information is updated at the refresh interval specified in the Settings dialog box which has a default of five seconds EWF cache memory in use This field displays the current amount of physical memory currently in use by the EWF cache rounded to the nearest megabyte MB Note that the EWF cache is allocated from the system page tables a subset of the total physical memory Available physical memory This field displays the current amount of available physical memory rounded to the nearest megabyte MB Available page table memory This field displays the current amount of available system page table memory rounded to the nearest megabyte MB System page table memory is usually the primary limiting factor to how large the EWF cache space may grow 3 4 2 4 EWF Monitoring group The EWF Monitoring group displays information about the EWF monitoring feature of Valueline EWF Administrator along with access to the Analyze
32. lcome to the Valueline EWF Administrator Tool This tool provides the ability to monitor and contral the Enhanced Write Filter EWF feature on Windows Embedded Standard PCs induding Enabling disabling and committing the EWF cache Setting a threshold to prevent failure upon exhausting EWF cache space Analysis of the system configuration to maximize EWF cache space To continue dick OK Figure 3 1 Splash screen 3 4 2 Valueline EWF Administrator dialog box The Valueline EWF Administrator dialog box is used to monitor and control EWF protection The automatic EWF monitoring feature is displayed and configured from this dialog box and the EWF usage analysis wizard is accessed from here EWF Status Memory Usage Protected volume C Current state ENABLED EWF cache memory in use 11 MB Mode RAM Reg Pending command NONE Available physical memory 1534 MB Available page table memory 1420 MB EWF Commands EWF Monitoring Low memory threshold Threshold action Figure 3 2 Valueline EWF Administrator dialog box PHOENIX CONTACT 3 3 EWF 3 4 PHOENIX CONTACT Note that closing the Valueline EWF Administrator dialog box using the red Close button in the upper right corner ofthe main dialog box does not terminate the program Instead the program is minimized to the notification area at the far right of the taskbar indicated by the Valueline EWF Administrator icon see
33. me that Valueline EWF Administrator is launched after an automatic action has occurred e g upon the next Windows startup if Valueline EWF Administrator is installed in the Startup folder an information message is displayed from the tray icon indicating the date time and specific action that was taken D Valueline EWF Administrator 4 x EWF Administrator performed an automatic Commit 84 Restart at 15 59 32 7 14 2011 Figure 3 24 Action notification message 3 20 PHOENIX CONTACT 3014 en A A Technical appendix A1 External Event Application Program Interface This section describes the Application Program Interface API which a software developer may use to programmatically detect the External Event action described in section 3 4 5 A 1 1 External Event Action The External Event threshold action sets a Windows named event upon reaching the Valueline EWF Administrators memory threshold The setting of this named event can be detected by other software applications to perform application specific handling of the event Named Event The named event that is set by Valueline EWF Administrator is called Global Valueline EWFAdmin ThresholdEvent This event is always created by Valueline EWF Administrator regardless of the Threshold Action setting and is only set when these conditions are met Valueline EWF Administrator is running EWF is currently enabled The Thr
34. n concept at least is to partition the system volume so that the available space is smaller than free system page table memory space However this solution is only practical to implement before installation of the Windows embedded OS image changing the system partition size after installing the OS image is not practical as it would require saving the image re partitioning the drive and Detection analysis and corrective actions for low page table entry issues http www microsoft com download en details aspx DisplayLang en amp id 12519 2 EWF overlay limits http blogs msdn com b embedded archive 2009 11 17 ewf overlay limits on windows embedded standard 2009 and 2011 aspx 3014 en A 3014 en A Enhanced Write Filter reloading the image Also this solution may be too restrictive possibly leaving insufficient space on the protected volume for normal operation of applications and the operating system 2 4 2 Reduce physical memory As explained in 2 3 1 The cause the counterintuitive fact is that there is often less available system page table memory when physical RAM is increased Therefore it is sometimes effective to increase available system page table memory by reducing physical RAM which can be accomplished by simply removing memory from the PC However this may only delay the inevitable EWF cache space exhaustion if the protected volume space needs exceed the available system page table memory 2 4 3 Valuel
35. n drive c One or more large empty files will be created and can easily be removed at a later time if more free space is desired After creating the files EWF protection will be automatically reenabled and followed by a system reboot Do you want to continue with the allocate operation Figure 3 21 Allocate Volume Space confirmation box Click the Yes button to begin the Allocate operation process Large empty files are created in the protected volume s root directory e g C with the naming convention EWFAdmin AllocatedFilennn bin where nnn is a unique number for each file Upon completion of the allocation operation EWF protection is automatically enabled and the system is rebooted At this point the system is now less likely to fail from EWF cache space exhaustion as it will more likely run out of disk space first There is still the possibility of EWF cache space exhaustion especially if large files are repeatedly written and deleted over time so it is still important to enable the Valueline EWF Administrator EWF monitoring threshold action to handle this possibility If more disk space is needed at a later date simply delete one or more of the above generated files and do an EWF Commit operation in Valueline EWF Administrator PHOENIX CONTACT 3 17 EWF 3 5 EWF Monitoring Actions Valueline EWF Administrator provides a user configurable low memory threshold and threshold action to be taken upon re
36. ory drop below this threshold the preselected action will be taken so that in the absence ofan operator exhaustion of available EWF cache space will be automatically avoided The allowed range for the low memory threshold is 1 MB to 10000 MB The default value is 100 MB Action override interval The action override interval determines the amount of time an operator has to override the automatic action when the low memory threshold is crossed A countdown message box is displayed see Error state on page 3 19 during which time the operator may choose to abort the automatic action and take some other manual intervention If no operator is present or if the operator does not respond to the message the threshold action takes place automatically The allowed range for the interval is O seconds to 3600 seconds 60 minutes The default value is 30 seconds It is recommended to set this value to a relatively low value especially for applications that are not typically attended by a human operator so that the action will take place promptly Threshold action When memory drops below the low memory threshold several options are available These options are selected using radio buttons The possible actions are None No automatic action This is the default selection Restart The system is automatically shut down and restarted Shutdown The system is automatically shut down Commit amp Restart The EWF cache is automatically committe
37. re the test Details button Click the Details button to display a listing of all the files created or modified during the test along with their current size in bytes The file sizes are cumulative and include any data already in the files before the test Valueline EWF Administrator Modified files Files modified during test File name C Usersttest AppData Roaming Microsoft Windows Recent Automatic C Usersttest AppData Roaming Microsoft Windows Recent Local Disk C Usersttest AppData Roaming Microsoft Windows Recent Revision tx C Windows System32 wbem Repository INDEX BTR C Windows gystem32iwbem Repository MAPPING2 MAP C Windows gystem32iwbem Repository OBJECTS DATA Displayed file sizes indude data existing in files before test Figure 3 16 Modified files dialog box PHOENIX CONTACT 3 13 EWF 3 14 PHOENIX CONTACT Recommendations The recommendations are based upon the test just completed see Figure 3 15 After reviewing the recommendations the user may click the Finish button to close the wizard The Settings dialog box will open so the user may conveniently view settings and perform the actions described in the recommendations 3 4 5 Settings Click the Settings button in the Valueline EWF Administrator dialog box to open Settings dialog box This dialog box provides the ability to configure options that govern the operation of Valueline
38. rmatted as follows ini lt INI file path amp name gt where lt INI file path amp name gt is a fully qualified drive or network path including the ini file name Note that the ini file name is not required to be EWFAdmin ini Valid ini option string examples are ini D EWFAdmin ini ini E EWFAdmin config ini ini network drive1 Config EWFAdmin ini It is recommended to configure the ini option in the program s Startup folder shortcut Target field see Automatic start up on page 3 1 For example C Tools EWFAdmin exe auto ini E EWFAdmin ini If the ini file is not found at the specified location during program start up default settings will be in effect lf the Startup folder is on a protected volume and EWF is currently enabled you will need to run Valueline EWF Administrator and use the Commit button to commit this change to the Startup shortcut to disk on the next reboot If Valueline EWF Administrator is invoked from the command line when an alternate ini file is desired the ini option must be used every time 3014_en_A 3014_en_A Valueline EWF Administrator 3 4 Valueline EWF Administrator 3 4 1 Splash screen The Valueline EWF Administrator splash screen is normally displayed upon program launch To suppress the splash screen at startup use the Automatic startup option see Automatic start up on page 3 1 We
39. sage 0 KB 0 00 KB sec Physical memory usage 8260 196 67 KB sec 100 38 KB sec System page table memory usage 4216 KB Usage Analysis Limiting factor System page table entries Estimated time remaining 4hours To view recommendations click Next Figure 3 14 EWF Usage Analysis Step 3 dialog box The following information is provided Test duration This field displays the duration of the testing performed in Step 2 in hours minutes and seconds Protected volume This field displays the protected volume s drive letter in parenthesis space used during the test rounded to the nearest kilobyte kB and usage rate in kB per second Physical memory This field displays the physical memory RAM space used during the test rounded to the nearest kilobyte kB and usage rate in kB per second System page table memory This field displays the system page table memory space used during the test rounded to the nearest kilobyte kB and usage rate in kB per second Limiting factor This field displays text describing the expected limiting factor for EWF cache usage Estimated time remaining This field displays the estimated amount of time remaining before EWF cache space is exhausted in days hours or minutes This is only a rough estimate calculated from the relevant usage rate above using the test duration as a representative usage period to extrapolate when space will be exhausted 3 12 PHOENIX CONTACT 3014_en_A 3014_
40. t warning message eeaaanae nennen 3 9 Valueline EWF Administrator Analyze wizard usss1uus2 3 9 EWF Usage Analysis Step 1 dialog box nuuuueeennsenneennenenneeenen 3 10 EWF Usage Analysis Step 2 dialog box nuusuesennnennnnnenenne nenn 3 11 EWF Usage Analysis Step 3 dialog box esesaaaaaaeaaaaaansccanaa 3 12 EWF Usage Analysis Step 4 dialog box nunsnesennsenneennenenneennen 3 13 Modified files dialog box EEN 3 13 SELINJS dialog DOK ai ana ee 3 14 lite un Melu Bag Let 3 14 Maximize System Pages confirmation message 1 3 16 Allocate Volume Space and EWF protection conflict message box 3 17 Allocate Volume Space confirmation box 3 17 EWF cache nearly full warning s eee aaaaaaea aaa aa aaananaaacaace 3 18 EWF Cache Tull Error eat ae 3 19 Action notification message ET 3 20 PHOENIX CONTACT B 1 EWF B 2 PHOENIX CONTACT 3014 en A
41. y 1549 MB Available page table memory 1424 MB EWF Monitoring Low memory threshold 100 MB Threshold action Restart EWF Commands Figure 3 7 Valueline EWF Administrator dialog box with Commit pending Commit amp Disable LIVE May be selected to perform the optional EWF Commit and Disable LIVE operation which commits the EWF cache to disk immediately without requiring reboot and leaves EWF protection disabled This has two distinct features which are negative in many cases Speed The Commit A Disable LIVE operation may take several minutes to complete Note that a normal commit usually takes substantially less time during the Windows shutdown operation Operational Since the Commit amp Disable LIVE operation leaves EWF protection disabled the normal CompactFlash write filtering is obviously disabled which is typically not desired for extended Windows Embedded OS operation 3 6 PHOENIX CONTACT 3014 en A 3014_en_A Valueline EWF Administrator With this option selected when the user clicks the OK button the EWF Commit 8 Disable LIVE command is immediately executed The EWF cache is immediately committed to disk which may take several minutes At completion of the commit operation a confirmation dialog is displayed Valueline EWF Administrator i CommitAndDisableLive successful EWF is now disabled Figure 3 8 CommitAndDisableLive message box Clic
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