In ,
Zaphod Beeblebrox wrote:
In article , says...
Okay, I thought there were recent discussions about it.
There might be, just not in the newsgroup (which never had a lot of
traffic even when XP Embedded was the current version).
I wish I had known that newsgroup existed back then. As I would have
been asking a lot of questions way back then. ;-)
[...]
30 seconds searching in Google Groups turned up this post and
others:
http://groups.google.com/group/micro....embedded/brow
se_thread/thread/304b4d42890bd5aa/1c600bfbdd395133?
hl=en&lnk=gst&q=ewf+corrupt#1c600bfbdd395133
See this is what I am talking about. They have other
partitions/drives that are not under the write protection with the
EWF enabled (generally it is only the system partition). And in
these cases, all bets are off as those other drives are still being
written too.
The post that the link points to says nothing about multiple
partitions, though I'll admit the OP does. It wasn't my intent to do
your homework for you, but rather to show that there are recorded
instances out there in the group. There are enough posts in the
archive discussing failures on single partition media that it is
accepted in embedded product engineering circles as real problem.
Thanks Zaphod! I plan on spending the next few weeks reading through the
archives to see what I can find. And you might have missed this post by
Lostgallifreyan, who explained to me how corruption could happen. See
below.
In ,
BillW50 wrote on Sat, 17 Mar 2012 07:47:27 -0500:
In ,
Lostgallifreyan wrote:
Failing on power loss can affect a CF card. Suppose a write is
driver- redirected to RAM disk. Suppose the power fails, and in that
last dying instant the driver fails, the calling function is still
trying to write, or for whatever other reason the write tries to
complete, unredirected. In the last instant of that instant, a CF
card might be written to at the last gasp of power. This is often
fatal for that card, never mind how many partitions are on it. If
this is what is happening, you might be SOL, not a lot you can do to
prevent the risk, except EXPLICITLY make every write operation go to
RAM disk, or wherever you want it to go. Relying on some driver to
redirect stuff is essentially a dangerous conflict of interest, a
bit like trusting other people's web spiders to respect your
robots.txt file if you run a website. If NOTHING at any level is
trying to write to a CF card or other Flash space, it should be
safer. I wouldn't use a system that depended on over-riding
dangerous existing behaviour, I'd want to change that behaviour at
source.
Okay now that makes sense and I can see that happening. And one could
avoid this problem electronically by disabling the write enable line.
I also mentioned to Lostgallifreyan that one could physically disable
the write enable to the drive. And regardless what else is happening,
that should prevent any shenanigans of any accidental writing to the
protected drive.
It is odd, I have routinely killed the power to my embedded devices and
I never had a problem. I suppose how the power fades throughout the
system determines how risky this practice would be on a given machine.
It is one of the reasons MS just isn't taken seriously in the embedded
world. It was kind of weird - MS had a big presence at ESC Boston 2010
and was practically laughed out of the conference, and didn't even
bother showing up at ESC Boston 2011. It's pretty clear they "just
don't get it" as far as embedded systems go.
I am not sure if there is enough demand for Windows Embedded anyway?
Since the appearance of netbooks, tablets, and such... it seems to make
more sense just running the stock Windows anyway, don't you think?
--
Bill
Gateway M465e ('06 era) - OE-QuoteFix v1.19.2
Centrino Core Duo T2400 1.83GHz - 2GB - Windows XP SP3