Re: Is there any crash-resistant file system for XPe?

Typically, EWF on CF uses a RAM overlay. Information in the RAM over lay is
already volital to begin with. Are you planning to use a Disk Overlay
instead of a RAM overlay?
If you are using a Disk Overlay, than you should look into to managing
different overlay levels within the Disk Overlay. Otherwise, EWf doesn't
have a sofisticated file check for corrupt data.

Regards,

Sean Liming
www.sjjmicro.com / www.seanliming.com
XP Embedded Book Author - XP Embedded Advanced, XP Embedded Supplemental
Toolkit.


"pnd_germany" <pnd_germany@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:175A7442-5CE7-4E01-89D8-D39972A59E76@xxxxxxxxxxxxxxxx
In my first training for XP embedded I learned some details about the EWF.
I
want to get a system with XPe and a crash-resistant file system. I can
write
protect my CompactFlash with the OS image and with help of the EWF on C:.
I
can use the EWF's disk overlay feature for a data partition on an
additional
hard disk drive, so that the partition d: is protected against crashes.

But what is about the overlay disk area? Is the EWF sophisticated enough
to
detect a defect overlay area and to reset all files within this area after
a
system crash which damages the file structure there? Is the dirty bit of
D:
the trigger for the EWF to reset the disk overlay area? There must be a
file
system in the overlay area cause of the mapped files which can be seen on
D:
and are located in the corresponding overlay area. Can Chkdsk repair and
detect files in the overlay area of D:?

I need some background informations to be sure to get a crash-resistant
system. It is ok if data in the overlay area is lost after a system crash,
but the system must be able to save new data in this overlay area after
such
a data lost again and again. I plan to avoid any "ewfmgr d: -commit"
command
to get this feature. The disk overlay offers permanent temporay data
unless a
system crash deletes it. I can store a lot of working data in the overlay
area, reuse this data after system resets and can protect the working of
the
whole system after crashes.

Does it work in this way?

It is better to think about a combination from XPe and WinCE?

WinCE could offer a API to XPe so that XPe can use a crash-resistant file
system that runs as part of the RTOS WinCE.


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