Re: Flash filesystem

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

Jernej:

I don't want to endorse any flash products publicly for several reasons.
Contact me directly, then I will let you know the solution I am using.

--
Bruce Eitman (eMVP)
Senior Engineer
beitman AT applieddata DOT net

Applied Data Systems
www.applieddata.net
An ISO 9001:2000 Registered Company
Microsoft WEP Gold-level Member


"turnsek" <turnsek@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:C72D20BE-DCFE-45BD-AFC0-ABC68F245755@xxxxxxxxxxxxxxxx
> Hi!
>
> We come to conclusion that we should try other filesystems and drivers.
Can
> you please advise us which will be good for our conditions.
>
> PS: We tried to power down (suspend) platform at least 5 seconds before
> reset hits and during stress tests. The filesystem also crashes after a
> number of this cycles. We are using standard Stratad driver (in public
> directory). Can we rule out software problems and concentrate on hardware?
>
> Thanks,
> Jernej Turnsek
>
> "Bruce Eitman (eMVP)" wrote:
>
> > Zhongwei:
> >
> > As we both know all to well, you left something out of the theoretical
> > discussion. The TFAT is only as stable as the media that it sits on,
which
> > can be made to be very unstable by the driver that manages it. Don't
> > misunderstand me, flash is very stable, but can be corrupted if
interrupted
> > while erasing or writing to a block, BUT TFAT can manage to survive that
as
> > Zhongwei describes.
> >
> > The problem can happen if the media driver moves bits around on the disk
to
> > **without** going through the TFAT, or taking other precautions to
prevent
> > corruption of data. I believe that MSFlash does compact the data on the
> > Flash to make room for new data, flash failures during that can be
fatal.
> > As Zhongwei points out this is all just theoretical though. I have not
been
> > able to prove this with MSFlash, mainly due to a shortage of source code
and
> > time. I have been able to prove this on other Flash drivers though. I
have
> > also found that suspend/resume can make it worse. Resets can be managed
> > better because the disk can be scanned when the driver is loaded and
> > repaired.
> >
> > --
> > Bruce Eitman (eMVP)
> > Senior Engineer
> > beitman AT applieddata DOT net
> >
> > Applied Data Systems
> > www.applieddata.net
> > An ISO 9001:2000 Registered Company
> > Microsoft WEP Gold-level Member
> >
> >
> > "Zhongwei Wang" <MWang@applieddata[dot]_net> wrote in message
> > news:OiHxm2IiFHA.2560@xxxxxxxxxxxxxxxxxxxxxxx
> > > Transaction safe file systems can reliably survive the hardware reset,
> > > theoretically, if it does it right. That is what they are advertised.
> > TFAT
> > > is not reliable enough right now then it only means it is not doing
> > > everything correct and it needs improvement.
> > >
> > > There is advertised idea of having two state file systems, working
state
> > and
> > > saved state, saved state is known good state. After a working state
> > > transaction is fully finished, working state is saved or converted to
> > saved
> > > state. And any working state transaction will only write to unused
> > blocks,
> > > i.e. blocks not being used by saved state, so saved state will not be
> > > touched. Does that sound perfect enough theoretically?
> > >
> > > --
> > > Zhongwei Wang
> > > Applied Data Systems
> > > www.applieddata.net
> > > Application - Ready embedded systems
> > > Microsoft Windows Embedded Partner
> > > Gold Level Member
> > >
> > >
> >
> >
> >


.

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