Date: Mon, 27 Mar 2006 13:01:45 -0500
To: "linux-os (Dick Johnson)" <linux-os@analogic.com>
Cc: "Artem B. Bityutskiy" <dedekind@yandex.ru>, linux@horizon.com,
       kalin@thinrope.net, linux-kernel@vger.kernel.org
Subject: Re: Lifetime of flash memory
Message-ID: <20060327180145.GD16773@csclub.uwaterloo.ca>
References: <20060326162100.9204.qmail@science.horizon.com> <4426C320.9010002@yandex.ru> <20060327161845.GA16775@csclub.uwaterloo.ca> <Pine.LNX.4.61.0603271242100.16721@chaos.analogic.com>
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From: lsorense@csclub.uwaterloo.ca (Lennart Sorensen)
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On Mon, Mar 27, 2006 at 12:44:50PM -0500, linux-os (Dick Johnson) wrote:
> Experimental data show that it is not possible to 'destroy' the
> chip by interrupting a write as previously reported by others.
> In fact, one of the destroyed devices was recovered by writing
> all the sectors in the device as in:
>  	 `dd if=/dev/zero of=/dev/hdb bs=1M count=122`.

I have a destroyed card here.  And I tried doing that.  A rep from
sandisk told me, that yes that model/generation of sandisk could
encounter that situation where the device was simply impossible to
access because of corruption during a write.  He also said the card
would have to be sent back to the factory to have the table reset.
Newer generations were going to fix that so it didn't happen again.

> Note that there __is__ a problem that may become a "gotcha" if
> you intend to RAW copy devices, one to another, for production.
> The reported size (number of sectors) is different between
> devices of the same type and manufacturer! Apparently, the size
> gets set when the device is tested.

Yeah, I load cards by partitioning, mkfs'ing, and extracting data.
Different manufacturers almost never have the same excact size.

Len Sorensen
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