Re: [Yaffs] Re: yaffs 2.0

Hi

Conceptually, making YAFFS1 work with 2k pages is straight forward, but there
are some subtle issues. YAFFS1 uses the stack for pages that it is working
on. The Linux kernel stack is not large, so 2k pages might break.

I would suggest that it makes more sense to wait for YAFFS2. At this stage
YAFFS2 is working in yaffs-direct mode on file emulation(that's how I develop
file system algorithms). I still need to hook up the mtd code to have YAFFS2
working with 2k pages in the kernel. I expect to have something in CVS within
2 weeks.

There is also a compatability mode in YAFFS2 so that it will support YAFFS1
format. The goal of this is that we move all development over to YAFFS2 and
obsolete YAFFS1.

Regards

-- Charles



On Tuesday 19 October 2004 21:21, Li Xin-a16157 wrote:
> Hi Charles,
>
> I am quite new to YAFFS. The flash device on my board is Toshiba 128MB,
> 3.3v, 8bit NAND flash. Its device ID is 0xF1 and has 2KB pages. My
> objective is to run the current YAFFS on my NAND flash. Which files in
> current YAFFS source should be modified to support 2KB page Nand? Will this
> kind of modification to support 2KB page need a lot of effort?
>
> Best Regards
> Li Xin
>
>
> -----Original Message-----
> From: Charles Manning [mailto:manningc2@actrix.gen.nz]
> Sent: 2004Äê10ÔÂ19ÈÕ 10:08
> To: Li Xin-a16157; Wookey; yaffs@stoneboat.aleph1.co.uk
> Cc: Li Xin-a16157
> Subject: Re: [Yaffs] Re: yaffs 2.0
>
> The major difference in YAFFS2 is the support for flash parts with zero
> rewrite. YAFFS1 keeps track of what data, files etc are deleted by the use
> of deletion markers. Writing the deletion marker has two down-sides: 1)
> Some flash parts do not tolerate any rewrites.
> 2) Obviously more writes == slower.
>
> YAFFS2 supports page sizes > 512bytes. You could hack YAFFS1 (ie.
> increase chunk size to 2k) to do this too, but YAFFS2 does straight off.
>
> Bigger chunks means less chunks per MB which means less RAM footprint.
>
> -- CHarles
>
> On Tuesday 19 October 2004 01:33, Li Xin-a16157 wrote:
> > They are essentially interchangeable, although only YAFFS2 will support
> > newer hardware (2k page size, no page rewriting).
> > -----------------------------------------------------
> >
> > Does this mean the current YAFFS doesn't support 2K page size Nand flash?
> >
> > Li Xin
> > Best Regards.
> >
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