Re: [Yaffs] Periodic Checkpointing

> -----Original Message-----
> From: yaffs-bounces@lists.aleph1.co.uk [mailto:yaffs-
> bounces@lists.aleph1.co.uk] On Behalf Of Ross Younger
> Sent: Thursday, 1 April 2010 6:51 PM
> To: yaffs@lists.aleph1.co.uk
> Subject: Re: [Yaffs] Periodic Checkpointing
>
> James Kehl wrote:
> > [block summaries]
> > Wouldn't this only be a gain for the inband-tags case, or when the
MTD
> > driver can't read out a page's tags without reading out the entire
page
> > as well (as some hardware ECC forces you to do)?
>
> It is true in my experience to say that tags mode is deathly slow - I
> don't touch it if I can possibly avoid doing so.
>
> OTOH there might well be an improvement to be had in inband tags mode
if
> you enable yaffs's own ECC on the tags and teach it to make a partial
> page read of just the tags area. However I'm concentrating on large
page
> devices for the time being, so don't have any time to look further
into
> this.
>

Just to confirm, you're talking about doing a partial page read of the
*main* page area, not the spare? i.e. only reading out the first 64
bytes or so of a page, not bothering with any of the standard ECC and
just relying on the separate tags ECC?

It's a rather interesting idea, even though it flew completely over my
head on first reading :)

You'd still get hit with the penalty on read/write speed, but this would
certainly reduce the mount-time overhead...

J