Re: [SPAM] FAT on NAND

["Jim Zeus" <jimzeus@vip.sina.com>]

> > What I am doing now is to build a filesystem which can be 
> > recognized on _raw_ NAND flash. So, I think FAT will be the only
> > choice(though I know it's very unstable). And I have following question now:
> 
> Windows won't recognise raw NAND flash anyway. You'll have to write
> _some_ kind of driver for Windows.
> 

Since the MTD block device(which include nand.c,mtdcore.c 
and mtdblock.c) is a block device, why I can't build
any filesystem on it? 
And, what's the difference between MTD block device and NFTL
if they stay on the same layer? Even though I cant use NFTL
because of some "silly patent problem" ,I still wanna know it,
thanks.


> > 1.How unstable would it be? Does it support: 
> >      a.journaling (crash/power-off safe ,I mean)
> 
> No.
> 
> >      b.bad block management
> 
> No.
> 
> >      c.wear levelling
> 
> No.
> 
> >      d.error correction
> 
> No.
> 
> >      e.something else I dont know to make the FS reliable
> 
> No.

Then, maybe the lower layer (MTD or NFTL) support it? or all the
stuff(a.b.c.d.e) are supported only by the file system 
(JFFS2/YAFFS,I mean)?

> 
> > 2.I have checked the NAND flash docoment (especially 
> > the "Filesystems supporting NAND"chapter) and I found out that
> > it seems no way to build a FAT on a bare NAND flash but only on 
> > the SmartMediaCards, am I right? Or the SM card and the bare NAND
> > are just the same thing when a FAT on it.
> > 3.Maybe I misunderstood,but David Woodhouse had told me that I should apply layers like FAT->NFTL->NAND if I wanna build a FAT on
> > a NAND flash.But I learned that the NFTL only support Doc from the
> > NAND flash document, isnt it? And what should I do to support the 
> > FAT ?
> 
> I told you to use the SmartMedia format, not NFTL. You can do that on
> any NAND hardware; NFTL has silly patent problems in some parts of the
> world.

Thank you, but what is the SmartMedia format? Sorry I am not 
familiar with that.

> 
> But really you should have a file system directly on the flash, not a
> translation layer pretending to be a block device.
> 

Do you mean build a totally new FS on a _bare_ NAND flash or on a MTD? 
You are so right, but I must build a FS which Windows can 
recognize and I have no enough time to do this before the time
limit.


> > 4.Everybody tells me that the Fat on a NAND is not reliable,but I 
> > think USB mass storage are based on NAND and got a FAT (or some 
> > filesystem which windows can recognize) on it, so ,how comes it 
> > happen?
> 
> It's not reliable, as you were told.
> 
> > BTW:Why my mail sent to the maillist always "awaits moderator approval"?
> 
> The ones you send as HTML get bounced for that reason. The rest are
> trapped because SpamAssassin doesn't like them...

I think my mail is txt but not in HTML.Whatever, I hope it won't 
happen anymore:)

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> -- 
> dwmw2
> 
> 
>