RAM fillup with EWF

[Carl Johan Jensen]

Hello !

We have a 130 MByte XPE image runinng OK with EWF configuret and running
perfectly. We have 128 MByte RAM.
How can I be sure that my OS will not, over time, fille my RAM with
unwritten files, loggings, paging files etc.

brgds

Carl Johan Jensen

 

[Slobodan Brcin \(eMVP\)]

Hi Carl,

XPE Image size is not important, what is important is remaining available size on the disk.
For instance if defragmenter is disabled and your system files occupy 130/180 MB of protected partition for instance. Then work case
scenario would be 50 MB of EWF usage since you can't write more different data to that partition.
But this is not something that you should allow to happen since other thing would complaint that you don't have enough empty space.
You should use filemon or some other file monitoring technique and determine what files are written to your protected partition and
then find a way to move them to unprotected one.

Read as some starting point:
http://msdn.microsoft.com/embedded/community/community/tips/xp/ramewf/default.aspx

Best regards,
Slobodan

 

[Carl Johan Jensen]

Thanks fir Your reply

I am using RAM based EWF - is there any way to monitor how large a portion
of unwritten data the EWF has put into my RAM.

brgds

Carl Johan Jensen

Hi Carl,

XPE Image size is not important, what is important is remaining available size on the disk.
For instance if defragmenter is disabled and your system files occupy

130/180 MB of protected partition for instance. Then work case

scenario would be 50 MB of EWF usage since you can't write more different data to that partition.
But this is not something that you should allow to happen since other

thing would complaint that you don't have enough empty space.

You should use filemon or some other file monitoring technique and

determine what files are written to your protected partition and

 

[Richard]

Yeah, but the problem is most of us don't run unprotected partitions. What
is the sense in having an unprotected partition on CF?

You would figure that in embedded XP, the ability to turn off some of the
logging would be beneficial, or do something like in my application, limit
the size of the logs. Ie an circular log, only keep the 200 entries and
when 201 comes about it over writes the oldest data in space 1.

So basically, are you saying if my image is 100 megs and is sitting on a 128
meg CF and I have 256 megs of ram it won't ever be an issue? If I
understand it correctly, the OS thinks I only have 28 megs free, so after it
writes 28 megs of information to the EWF RAM, the os is going to start to
issue "out of drive space"

Richard

Hi Carl,

XPE Image size is not important, what is important is remaining available size on the disk.
For instance if defragmenter is disabled and your system files occupy

130/180 MB of protected partition for instance. Then work case

scenario would be 50 MB of EWF usage since you can't write more different data to that partition.
But this is not something that you should allow to happen since other

thing would complaint that you don't have enough empty space.

You should use filemon or some other file monitoring technique and

determine what files are written to your protected partition and

 

[Slobodan Brcin \(eMVP\)]

Hi Richard,

So basically, are you saying if my image is 100 megs and is sitting on a 128
meg CF and I have 256 megs of ram it won't ever be an issue?

Right! It won't be issues with RAM EWF usage since you can't change more than 28 MB of data on disk. (Unless you do updated to OS
binaries themselves by DUA, but here you have control)

the os is going to start to issue "out of drive space"

Yes, but this does not help you since many (unpredictable) things can stop working so you must never find your self in this
situation.

Best regards,
Slobodan

 

[Slobodan Brcin \(eMVP\)]

Use ewfmgr or ewfmgr c:

Best regards,
Slobodan

Thanks fir Your reply

I am using RAM based EWF - is there any way to monitor how large a portion
of unwritten data the EWF has put into my RAM.

brgds

Carl Johan Jensen



130/180 MB of protected partition for instance. Then work case
thing would complaint that you don't have enough empty space.
determine what files are written to your protected partition and

 

[KM]

Carl,

The best answer you would probably get on the device in the field.
Create a simle agent app (that either call to EWF API or to "ewfmgr") that
will log EWF overlay usage to a file.
Then review the log after a few days of user work and see if the usage is
beyong your estimation. It is not a stress test but sometimes the field
trial is what you want.

KM