beginners mtd/jffs question

beginners mtd/jffs question

[Eric Nelson]

We are starting a project which will use a commercial SBC, x86 based.  I am sold
on MTD/JFFS2, but don't understand exactly what we need to look for.  When I
looked at the database of MTD devices, I just saw some AMD and Intel linear
flash.  Here are my questions:

Isn't it better to use plain NOR linear flash than DOC, because then JFFS2 has
complete control?

Is the DOC/JFFS2 a good solution?  I mean, it seems like w/ the commercial
SBC's, the only options are CompactFlash (Ugh!), or DOC.  Is there some type of
PCMCIA flash that meets MTD?  Are there commercial boards w/ linear MTD flash?

Re: beginners mtd/jffs question

[David Woodhouse]

> Isn't it better to use plain NOR linear flash than DOC, because then JFFS2
> has complete control?

JFFS2 has complete control of a DiskOnChip. It's only an ASIC to do 
hardware ECC and a handful of NAND flash chips. But JFFS2 doesn't yet 
support NAND flash properly, so at the moment plain NOR linear flash is 
best.

> Is the DOC/JFFS2 a good solution? 

Not right now, maybe soon.

> I mean, it seems like w/ the commercial SBC's, the only options are
> CompactFlash (Ugh!), or DOC. 

> Is there some type of PCMCIA flash that meets MTD?

Hard to get hold of now - most people stopped making it in favour of CF. 
Cisco still use it, but obviously that's fairly expensive, being Cisco.
It's easy enough to make a map driver for it if you actually _have_ one, 
but most people don't, so nobody's bothered to write that driver yet.

>  Are there commercial boards w/ linear MTD flash? 

Yes. http://www.arcomcontrols.com/products/icp/pc104/processors/SBC_GXm.htm

Just looking in the drivers/mtd/maps directory will give you some boards to 
look for.

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dwmw2