From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Lord <liml@rtr.ca>
Subject: Re: Compact Flash Question
Date: Thu, 08 May 2008 09:26:37 -0400
Message-ID: <4822FF8D.7020805@rtr.ca>
References: <48215673.3060201@wpkg.org>	 <e2e108260805070044v42f596bbj39c5b52b6f0a096@mail.gmail.com>	 <48216039.3070001@wpkg.org> <4821A12F.2020800@aitel.hist.no>	 <4821C462.2000108@free.fr> <e2e108260805070946t63f35e36q6960bdff11fecd8c@mail.gmail.com>
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To: Bart Van Assche <bart.vanassche@gmail.com>
Cc: =?UTF-8?B?U3TDqXBoYW5lIEFOQ0VMT1Q=?= <sancelot@free.fr>, Helge Hafting <helge.hafting@aitel.hist.no>, Tomasz Chmielewski <mangoo@wpkg.org>, LKML <linux-kernel@vger.kernel.org>, YSadgat1@gcte.com, linux-os@analogic.com, Alan <alan@lxorguk.ukuu.org.uk>, Linux IDE <linux-ide@vger.kernel.org>, Jeff Woods <jeff@jeffwoods.us>

Bart Van Assche wrote:
> On Wed, May 7, 2008 at 5:01 PM, St=C3=A9phane ANCELOT <sancelot@free.=
fr> wrote:
>> we use  silicon systems CF  with wear leveling inside  , we write a =
few
>> kb data back each 1/4 h  on it.(log /tmp files  are redirected to ra=
m)
>=20
> Silicon Systems CompactFlashes are the among the most reliable
> CompactFlashes I have used in embedded devices. See also
> http://www.siliconsystems.com/silicondrive/whitepapers/SSWP03-Enduran=
ce-R.pdf
> for a whitepaper that explains their wear leveling and error
> correction algorithms. Furthermore, Silicon Systems has a technology
> called SiSMART that allows to monitor by how far the CompactFlash is
> worn out, such that it can be monitored whether or not it is time to
> replace the CompactFlash. (Note: I am not affiliated in any way to
> Silicon Systems.)
=2E.

Mmm.. according to that document, the "dynamic wear leveling" devices
might benefit from having Linux issue CF-Erase commands to unallocated =
sectors,
so that the onboard CF controller can then add those sectors to the wea=
r-leveling
rotation scheme.

There was discussion at LSF'08 about possible filesystem hooks that cou=
ld
be used for this (and other) purposes when deleting files.

Cheers