ewfmgr with serial port open RRS feed

  • Question

  • Hi,

    Im using XPE for my application. Recently i got an issue with serial port (on board and card). Before enable ewfmg, everything works fine, but when i enable ewfmgr with my application runnning and serial port open i encounter problem after i reboot the PC. After reboot with serial port CONNECTED to a device, my serial port is not working and it popup the following msg : 
                  "Another program is using the selected Telephony device.Try again after the other programs complete."

    Even when i disable ewfmgr, this problem still occurs. When i reboot with serial port disconnect, it works finds when i connect back serial port to the device.
    Anyone happen to encounter this problem before or is there any solution to this problem ... TQ :(
    Wednesday, June 17, 2009 2:05 AM

All replies

  • FYI - Enabling and Disabling EWF does not happen on the fly. It requires a reboot to take effect. (You should follow /enable and /disable commands with a restart)

    From your description it appears your application is unable to use the serial device when EWF is active. Please provide the following information to help understand your problem

    1. What EWF confgiuration are you using ? (EWF RAM mode / Disk mode / Ram Reg)
    2. Are you protecting all partitions or just the OS partition
    3. Can you tell us a bit more about the application ? Does it have a driver too ?


    Srikanth Kamath [MSFT]
    Wednesday, June 17, 2009 6:00 AM
  • Hi ,

    thanks for your info srikanth.

    Im using EWF Ram Reg and OS partition only. My application will continuous receive signal from an indicator once the app run.
    Everything works fine before EWF and after EWF serial comm fail. Then after even I disable EWF still fail. On one condition for the port to work is to reboot without connecting the indicator to the serial port (PC) and wait till it goes to desktop only connect the indicator to serial port(PC).

    The comm port should be close after reboot even it is connected or not as my app is not running.


    Wednesday, June 17, 2009 7:12 AM
  • Hi edwinloh -

    The most common reason for application failure in the presence of a write filter like EWF is the need to persist configuration information. For example - if the application writes to the registry and expects this value to persist across reboot. But if the registry is backed up in a protected volume , and the write filter is in discard mode (RAM / RAM REG mode for EWF), the changes will not persist. Hence the application cannot work correctly.

    Do you see any such requirements for your application ?


    Srikanth Kamath [MSFT]
    Wednesday, June 17, 2009 3:45 PM