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Subject: Re: UBIFS support for SLC and MLC
From: Artem Bityutskiy <dedekind1@gmail.com>
To: "Matthew L. Creech" <mlcreech@gmail.com>
Date: Fri, 22 Jul 2011 11:22:37 +0300
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Cc: linux-mtd@lists.infradead.org, John <jtburch62@gmail.com>
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On Wed, 2011-07-20 at 18:17 -0400, Matthew L. Creech wrote:
> On Wed, Jul 20, 2011 at 4:53 PM, John <jtburch62@gmail.com> wrote:
> > I'm exploring flash memory technology for a new product and am
> > confused about whether UBIFS fully supports SLC and MLC NAND.  When I
> > read the FAQ at
> > http://www.linux-mtd.infradead.org/faq/ubifs.html#L_ubifs_mlc, it
> > states that one of the two aspects of MLC that are not supported is
> > "program disturb".  However, the document link referenced in the same
> > FAQ (http://www.linux-mtd.infradead.org/faq/ubifs.html#L_ubifs_mlc)
> > states that "program disturb" is common to both SLC and MLC - just at
> > different error rates.
> >
> > 1.  How does UBIFS address the "program disturb" effect in SLC NAND?
> >
> > 2.  Why doesn't the FAQs explanation for how UBIFS handles "read
> > disturb" apply to "program disturb"?
> >
> 
> I think the first "read disturb" that is discussed in the FAQ is a
> rather specific case: repeated READs of a page cause bit-flips on that
> same page.  The solution is simply to correct the block on-flash
> ("scrub" it) whenever a bit-flip is detected.

Matthew, John, to make sure this good conversation is not lost in the
mailing list archives, it would be great to amend the FAQ by sending a
patch against mtd-www: git://git.infradead.org/mtd-www.git

It is quite trivial to change it.

-- 
Best Regards,
Artem Bityutskiy