SD card unpartitioned space -- used for swap?

James Cameron quozl at laptop.org
Mon Nov 22 19:20:32 EST 2010


On Mon, Nov 22, 2010 at 05:43:18PM -0600, Mikus Grinbergs wrote:
> > Assuming OLPC isn't using TRIM support on the SD cards, writes to the
> > swap space are indistinguishable from writes to any other space on the
> > card.  That means that writes to the swap "partition" could potentially
> > corrupt other data on the card, especially if it occurs less than 30s
> > before removal of power (or whatever that evil keepout time is).
> 
> ...
> 
> Also, I'm not familiar with "evil keepout time".  But note that on the
> new XO-1 F14 build, the "shutdown" time-lapse is only a few seconds.
> If actually 30s are needed to keep the SD circuitry happy, perhaps a
> delay (and a Release Notes explanation) should be added to the OLPC.

I suspect the "evil keepout time" is the time after the last write
request to the card and the removal of power.  It is why current XO-1.5
EC firmware blinks the power LED for some seconds on power off.

We only know it affects the cards we ship, and no idea if it affects
that external card you're using.

-- 
James Cameron
http://quozl.linux.org.au/


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