FTL of compact flash card

FTL of compact flash card

[Jeff Lin]

Hello, all, 

 First, Happy new year to you!

 I am looking for a FTL (flash translation layer)code 
that will emulates the flash memory as a IDE  disk 
for the controller IC inside the compact flash card. 

The FTL will need to do logical to physical address
mapping, bad block management, and wear level
algorithm. There is no File system needed, instead,
the FTL will talk to the native file system. 

Is there any open source code of FTL available? Can
NFTL or JFFS/JFFS2 be tailored for this purpose? As
for commercial FTL, which commercial code is
good/reliable and relatively inexpensive?

Thank you very much for help,
Jeff




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Re: FTL of compact flash card

[Charles Manning]

>From what I read here, what you want is a mapping that provides a block-wise 
interface to the flash.

JFFSx is a file system. That will not do what you want.

What you need is some block-like FTL like NFTL or whatever goes on inside a 
Compact Flash or ATA card. I am not aware of any open source code that will 
do what you want. As far as I can tell all this code is fiercely guarded by 
companies like Sandisk and MSystems.

Maybe someone can be more helpful.....

-- CHarles


On Wed, 01 Jan 2003 08:42, Jeff Lin wrote:
> Hello, all,
>
>  First, Happy new year to you!
>
>  I am looking for a FTL (flash translation layer)code
> that will emulates the flash memory as a IDE  disk
> for the controller IC inside the compact flash card.
>
> The FTL will need to do logical to physical address
> mapping, bad block management, and wear level
> algorithm. There is no File system needed, instead,
> the FTL will talk to the native file system.
>
> Is there any open source code of FTL available? Can
> NFTL or JFFS/JFFS2 be tailored for this purpose? As
> for commercial FTL, which commercial code is
> good/reliable and relatively inexpensive?
>
> Thank you very much for help,
> Jeff
>
>
>
>
> __________________________________________________
> Do you Yahoo!?
> Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
> http://mailplus.yahoo.com
>
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> http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: FTL of compact flash card

[Henrik Nordstrom]

On Wed, 1 Jan 2003, Charles Manning wrote:

> >From what I read here, what you want is a mapping that provides a block-wise 
> interface to the flash.
> 
> JFFSx is a file system. That will not do what you want.
> 
> What you need is some block-like FTL like NFTL or whatever goes on inside a 
> Compact Flash or ATA card. I am not aware of any open source code that will 
> do what you want. As far as I can tell all this code is fiercely guarded by 
> companies like Sandisk and MSystems.

There is at least 4 such layers in the Linux MTD kernel sources:

  NFTL. Compatible with the NFTL design and implementation by MSystems for
their DOC devices. However, any use of NFTL on other devices will likely
be in violation to their patent unless a license is aquired.

  FTL. Also covered by a M-Systems patent with a special grant for use in
PCMCIA. See ftl.c for details.

  mtdblock, linear block level access to flash memory. No wear leveling as
far as I know.

  The journalling level of jffs. Has wear leveling.

  The journalling level of jffs2. Has wear leveling.


For most purposes I suspect actually using the JFFS2 filesystem is the
best fit. Gives you efficient wear leveling (inlcluding not caring about
deleted content) and reasonable data integrity protection.

Regards
Henrik