J
Jay
My goal here is to have a stateless machine
- It boots the same every time
- The Compact Flash is never written, preventing wear-
related failures
- I don't need or want any "persistent" data stored on
the CF.
(1) I read somewhere that a RAM EWF overlay is allocated
from non-paged pool, and non-paged pool can be a maximum
of 256 MB. Are these limits correct? Can an EWF RAM
overlay allocate most of that non-paged pool? Assuming
there is enough RAM, how big can the EWF RAM overlay be?
(2) I believe that if the RAM overlay "fills up", you can
get a message such as "Delayed Write Failed. Windows was
unable to save......". Can the user then delete some
files and retry the operation in the same manner as if it
was a floppy drive running out or space?
(3) If Lazy Write is not enabled, is it guaranteed that
the EWF overlay data will not be written to the underlying
media, even if the RAM overlay fills up?
(4) What about shutdown? Can it be guaranteed that EWF
overlay data will not be written to the underlying CF
media on system shutdown?
(5) I'm a little confused about the effects of removable
and non-removable media. If I have a standard CF card (and
did not go through the process with the manufacturer to
get it designated as non-removable), then I can't
partition the CF card and therefore the entire CF will be
protected by EWF. I would need to use the Registry
editing procedure outlined in the article "Using Compact
Flash with the Enhanced Write Filter" to enable the EWF.
Are these assumptions correct ?
(6) Assuming I use the method in in item (5), and it is
time for some software maintenance, I understand that a
EWFMGR commit and disable operation will make my CF
writeable again after the next boot. Does it write all
the overlay data to the CF immediately at the time of the
EWFMGR operation? After the next boot, can I use the
Registry Editing process to re-enable the EWF as before?
I sure would appreciate answers to these questions.
Thank you very much for your help.
Jay
- It boots the same every time
- The Compact Flash is never written, preventing wear-
related failures
- I don't need or want any "persistent" data stored on
the CF.
(1) I read somewhere that a RAM EWF overlay is allocated
from non-paged pool, and non-paged pool can be a maximum
of 256 MB. Are these limits correct? Can an EWF RAM
overlay allocate most of that non-paged pool? Assuming
there is enough RAM, how big can the EWF RAM overlay be?
(2) I believe that if the RAM overlay "fills up", you can
get a message such as "Delayed Write Failed. Windows was
unable to save......". Can the user then delete some
files and retry the operation in the same manner as if it
was a floppy drive running out or space?
(3) If Lazy Write is not enabled, is it guaranteed that
the EWF overlay data will not be written to the underlying
media, even if the RAM overlay fills up?
(4) What about shutdown? Can it be guaranteed that EWF
overlay data will not be written to the underlying CF
media on system shutdown?
(5) I'm a little confused about the effects of removable
and non-removable media. If I have a standard CF card (and
did not go through the process with the manufacturer to
get it designated as non-removable), then I can't
partition the CF card and therefore the entire CF will be
protected by EWF. I would need to use the Registry
editing procedure outlined in the article "Using Compact
Flash with the Enhanced Write Filter" to enable the EWF.
Are these assumptions correct ?
(6) Assuming I use the method in in item (5), and it is
time for some software maintenance, I understand that a
EWFMGR commit and disable operation will make my CF
writeable again after the next boot. Does it write all
the overlay data to the CF immediately at the time of the
EWFMGR operation? After the next boot, can I use the
Registry Editing process to re-enable the EWF as before?
I sure would appreciate answers to these questions.
Thank you very much for your help.
Jay