[Yaffs] Re: Use YAFFS in RTOS

[Wookey]

+++ Austin Chen [05-08-23 19:52 +0800]:
> Dear All,
> 
>     I am new to here. I have a design use the NAND Flash File System designed by myself. It has bad block management but lack of wear leveling. It also use a non-standard FAT to store files. Now I want to improve my design and incorporate a full-featured Flash File System.
 
> Is the YAFFS or YAFFS2 suitable for embedded design with RTOS? 

Yes. The YAFFS Direct variant is designed with this purpose in mind. You
just need to provide a few functions (read/write/inet/erase NAND, get time,
get/drop mutex). 

It has been used with pSOS and Vxworks and at least one in house system.

> My design use Nucleus Plus RTOS and Nucleus File system. 

A port for this OS has not yet been done (SFAIK). You will need to do some
work to merge it in. If Nucleos is not GPL-compatible then you will need to
get a licence from Aleph One to use the code in a non-GPL context.

> The Nucleus File is used to access a USB Disk. Since there already has a
> File System, I hope the YAFFS can be used as a pure FTL (Flash Translation
> Layer) to make the NAND Flash as disk like block device. Is it possible to
> split FTL and File System from YAFFS?

I don't think this is possible. YAFFS is a whole filesystem, and presents a
posix-style interface to the OS (open, read, write, rename etc). This should
be reasonable easy to integrate into nucleous. Trying to just use it as an
FTL/block device is really the wrong tool for the job. Charles may wish to
comment further here?


Wookey
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