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Date: Tue, 20 Sep 2005 15:38:32 +0200
From: Peter Menzebach <pm-mtd@mw-itcon.de>
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To: "Artem B. Bityutskiy" <dedekind@yandex.ru>
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Cc: Linux MTD <linux-mtd@lists.infradead.org>
Subject: Re: data  loss on jffs2 filesystem on dataflash
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Artem B. Bityutskiy wrote:
>> Artem B. Bityutskiy wrote:
>> I glanced at the manual. Uhh, DataFlash is very specific beast. It 
>> suppoers page program with built-in erase command... So DataFlash 
>> effectively may be considered as a block device. Then you may use any 
>> FS on it providing you have wrote proper driver? Why do you need JFFS2 
>> then :-) ?
I do need some wear leveling (and a filesystem which supports block 
sizes of 1056 bytes ;) )

>> JFFS2 orients to "classical" flashes. They have no "write page with 
>> built-in erase" operation.
>>
>> Didn't read the manual carefully, what do they refer by "Main memory 
>> array"?
The main memory array is the flash itself with pages of 1056 bytes

>> BTW, having 8*1056 write buffer is not perfect ides, better make it as 
>> small as possible, i.e., 1056 bytes.
At the moment, the write buffer = reported erase block size. Is this 
neccessary that this is equal?

my reasons for setting erase block size to 8(16)*1056:
1. my lazyness -> I have to patch the mkfs.jff2 every time, since it 
makes a guess, that -e 1056 is not a very good idea (at lest the 
versions some times ago)

2. It seemed to me, that jffs2 boots faster, if the number of blocks is 
smaller.

3. A guess without proof: jffs2 likes blocks which are not too small

Best regards
Peter

-- 
Peter Menzebach
Menzebach und Wolff IT-Consulting GbR
Phone +49 751 355 387 1