On Friday 04 April 2008 21:38:24 Zavi wrote:
> Does this restriction mean that you can't for example perform a
> program to the data area of a page X, move on to programing other
> pages and erase units, and later program the spare area of page X?
You really mention two issues here:
* Partial page programming: This is where the page is programmed in more than
one write. For example, write some data bytes in a page, then write some more
data bytes or write the spare area.
* Sequential page writing: This means writing page 0 in the block, followed by
page 1 in the block etc until the block is filled. The sequencing relates to
the page write order within the block.
Partial page programming is bad for many modern NAND parts. non-sequential
writing is bad too.
Older flash parts would tolerate many (4 or more) partial page programming
operations and were not fussy about sequential programming.
>
> Thank you
>
> On Sun, Mar 2, 2008 at 9:45 PM, Charles Manning <manningc2@actrix.gen.nz>
wrote:
> > On Wednesday 27 February 2008 03:46:51 shizheng@Alumni wrote:
> > > Thanks a lot. I have another question to ask.
> > > Do all kinds of 2kB-page NAND flash obey to the sequential page
> > > writing order rule?
> >
> > Almost all modern 2k+ flash have a restriction in the pages should be
> > written in sequential order. While they might still work in other write
> > orders this tends to make them disrupt more bits.
> >
> > That is one of the reasons yaffs2 was designed to only do sequential
> > writes.
> >
> > -- Charles
> >
> > > rohit h wrote:
> > > >> It has a program limitation that the program addressing should
> > > >> be done in sequential order in a block, i.e. random page address
> > > >> programming is prohibited.
> > > >>
> > > >> We are new to Yaffs, so I wanna know if yaffs support such kind of
> > > >> NAND device.
> > > >
> > > > Yaffs2 only programs sequentially in a block, starting from page 0
> > > > and ending at the last page.
> > > >
> > > > Quote from http://www.yaffs.net/node/38:
> > > > "The original motivation for YAFFS 2 was to add support for the new
> > > > NAND with 2kB pages instead of 512-byte pages and strictly
> > > > sequential page writing order."
> > >
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