To: linux-kernel@vger.kernel.org
From: Sergei Organov <osv@javad.com>
Subject: Re: o_sync in vfat driver
Date: Tue, 28 Feb 2006 16:52:29 +0300
Message-ID: <du1kj0$f1j$1@sea.gmane.org>
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"linux-os \(Dick Johnson\)" <linux-os@analogic.com> writes:
> On Mon, 27 Feb 2006 col-pepper@piments.com wrote:
>
>> On Mon, 27 Feb 2006 22:32:07 +0100, linux-os (Dick Johnson)
>> <linux-os@analogic.com> wrote:
>>
[...]
> It takes about a second to erase a 64k physical sector. This is
> a required operation before it is written.
> Since the projected life of these new devices is about 5 to 10 million
> such cycles, (older NAND flash used in modems was only 100-200k) the
> writer would have to be running that "brand new device" for at least 5
> million seconds. Let's see:

What FLASH are you talking about? I work with NAND FLASH chips directly
in embedded projects, and for both Toshiba and Samsung NAND FLASH the
erase time of 128Kb (64K words) block is 2 milliseconds typical. Page
program time is 0.3 milliseconds typical, so, having 64 pages per block,
total erase-write block cycle is about 22ms.

Those chips indeed support about 100K program/erase cycles. Well, maybe
there are some new NAND FLASH chips that support more program/erase
cycles (just checked Samsung but found none), but I doubt they are 1000
times slower for block erase anyway.

-- Sergei.

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