Re: [gentoo-user] Noisy dd operation

[Alan McKinnon]

On Sun, 17 Jun 2012 21:03:35 -0400
Michael Mol <mikemol@×××××.com> wrote:

> > But what is your actual query? About the write speed?
>
> No, not really. TBH, I wasn't expecting to be able to consistently
> write quickly to the beginning of the card, but slowly at the end; I
> wanted to make sure the card wasn't going bad given the abruptness of
> the change. Actually, the more I think about it, I think it happened
> at the 2GB boundary, where some funky pin logic changes. (And where SD
> becomes SDHC). So I think that's where the performance shifted. Maybe
> I'll invest in a bunch of fast 2G cards, if it means the performance
> is consistent, and I'd still fit just under 200 shots.

I'm finding that SD and SDHC cards are not exactly reliable[1] when you
start write hammering them like they were spinning disks :-)

Remember early memory sticks and how 1000 writes was all you'd get from
some? Sort of like that. What prompted my response was I had just been
doing lots of writes and rewrites to my test cards for the Raspberry
Pi, and the latest one failed. Similar sort of nonsense message to what
you got, just from the mmc subsystem (I have a built-in card slot that
isn't USB). And that also happened somewhere near the 2G boundary
now that I figure the numbers back in my head.

[1] I'm talking of the cards regular folk can buy at the corner 'puter
shop, not the seriously high-quality ones that eg Dell ship with VMWare
servers. Those I believe are vastly superior (at a price)

-- 
Alan McKinnnon
alan.mckinnon@×××××.com