XO memory size

James Cameron quozl at laptop.org
Sun Mar 1 06:26:26 EST 2009

On Sat, Feb 28, 2009 at 11:05:51PM -0800, Derek Zhou wrote:
> On Saturday 28 February 2009 05:51:40 pm James Cameron wrote:
> > > 3, every once in a while (10 mins or so) there is a message in console like: 
> > > JFFS2 warning: jffs2_sum_write_sumnode: Not enough space for summary, padsize=-60
> > 
> > That matches a known problem.  The JFFS2 filesystem is in a suboptimal
> > state.
> Can you tell me more about this.

Yes, but I don't know much more about it.  The suboptimal state seems be
triggered by extensive use of the filesystem, or filling to capacity.
It is so easy to fix (by reflashing) that I've never seriously
investigated it.  To investigate it I would look for changes to JFFS2
kernel code since debxo-0.4, and check for trac tickets on
dev.laptop.org, and possibly analyse the filesystem somehow.  I'm not
experienced in that, and I don't have the filesystem available to me.

> I installed debxo-0.5 on a usb drive and rxvt
> speed seems normal. So it comes down to either the jffs2 or the internal nand.

To test for that, use the debxo 0.5 booted from USB to test reading the
NAND flash without using the filesystem.  I haven't derived such a test
yet, maybe you have some ideas.  If you get a block read performance
that is consistent with other units, then you can exclude the NAND flash
as cause, leaving only the JFFS2 filesystem as the cause.

> I thought jffs2 on raw nand is supposed to be better than non-flash
> aware fs on a cheap usb stick...

I don't know about that.  Better in what way?

James Cameron    mailto:quozl at us.netrek.org     http://quozl.netrek.org/

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