Strange behaviour Transcend CF

[Petr Odlozil]

Hello,

first thanks to all for advices, which helped greatlly with my
strungle with WINXPE. )

Now I have a strange problem with Transcend 45x CF card.
I've copied the image 2 times. First time I had the problem with Drive
letters assignment, so I've tried to solve it by the tip :
(Make your Runtime think it's on C:\ While it's .....
http://msdn.microsoft.com/embedded/community/community/tips/xp/rtpartin/default.aspx)

FBA went OK and did one reboot and then showed a dialogue window
reseting the setup flag and restarted computer again. After this reboot,
the CF wasn't possible to read at all, even in a card reader at the
desktop PC. The PC only suggested to format it again. So I did it.

Now I can read the card under WIN XP, but not in DOS mode. I can't
change to the drive letter (but BIOS found it correstly).

Any suggestions ?

Petr

 

[Petr Odlozil]

Hello,

first thanks to all for advices, which helped greatlly with my strungle
with WINXPE. )

Now I have a strange problem with Transcend 45x CF card.
I've copied the image 2 times. First time I had the problem with Drive
letters assignment, so I've tried to solve it by the tip :
(Make your Runtime think it's on C:\ While it's .....
http://msdn.microsoft.com/embedded/community/community/tips/xp/rtpartin/default.aspx)


FBA went OK and did one reboot and then showed a dialogue window
reseting the setup flag and restarted computer again. After this reboot,
the CF wasn't possible to read at all, even in a card reader at the
desktop PC. The PC only suggested to format it again. So I did it.

Now I can read the card under WIN XP, but not in DOS mode. I can't
change to the drive letter (but BIOS found it correstly).

After FDISK I can see the media again,
but who knows .. if I try to put image on it and restart, will that
happen again ?
Could have FBA changed the compact flash somehow , because it was set in
registry (Mounted) as a C drive ?

P.

 

[KM]

Petr,

I have only one suggestion for you - never run FBA on CF cards. It may (and
probably will) damage the media.
Instaed, run it on HDD and then copy post-FBA image.

MountedDevices key has nothing to do with the format and FS on the card.

KM

 

[Guest]

I am a little confused by this. Microsoft has instructions on setting up CF
as a bootable device (and I do not see any warnings to not run FBA on a CF).
I do not have a free HDD available to run FBA on my embedded system. My
system boots from a CF, programmed nonremovable, I have run FBA on it many
times and it boots fine, should I take steps to acquired a HDD to run FBA.

 

[Dave August]

YES!!!

FBA does many 1000's (10,000?.. 100,000?) writes to the registry. If you
continue to do FBA on your CF pretty soon it will be useless. Go read your
CF spec, the cards have a finite amount of write till the die.. :-(

Dave

 

[KM]

Dee,

Speaking of Microsoft documentation:
http://msdn.microsoft.com/library/en-us/xpehelp/html/xetbsHowToCreateCompactFlashRun-TimeImage.asp (Step #4):
"
Running FBA directly on the CompactFlash device can be time consuming and write-intensive. You can deploy your run-time image to a
hard disk to run FBA, then copy the post-FBA run-time image to the CompactFlash device.

"

KM

 

[Slobodan Brcin \(eMVP\)]

Dave,

FBA does many 1000's (10,000?.. 100,000?) writes to the registry. If you
continue to do FBA on your CF pretty soon it will be useless. Go read your
CF spec, the cards have a finite amount of write till the die.. :-(

Actually registry writes are not such a problem since they are scattered.
But on FAT during the FBA few certain sectors are written in counts of
several thousands this is what damage these sectors and then we all know
what happen.

FBA on NTFS do less damage to same sectors, but write count is also
unacceptable.

Regards,
Slobodan

 

[Guest]

Thank you for this information. And I hate to continue to ask questions on
the same subject (I have a separate post on this issue), but I want to make
sure I am clear before I proceed.

So then adding EWF to the configuration is an alternative to adding a HDD,
correct?,

the way I understand it, if I add EWF using RAM mode, all writes take place
in RAM, saving the CF from writes, and also these changes are lost on reboot
because they are in ram. I am assuming the changes made during FBA should be
permanent, but they can't be with RAM mode, so how does this work?

 

[KM]

Dee,

So then adding EWF to the configuration is an alternative to adding a HDD, correct?,

No.. Notheing in EWF is hardware related. (pure software component)

the way I understand it, if I add EWF using RAM mode, all writes take place
in RAM, saving the CF from writes, and also these changes are lost on reboot
because they are in ram.
Correct.

I am assuming the changes made during FBA should be
permanent, but they can't be with RAM mode, so how does this work?

It works as you just described above.
This is why during FBA you need EWF disabled.

KM