Any restrictions or recommendations regarding SD cards?

Christoph Derndorfer christoph.derndorfer at
Thu Mar 24 19:47:58 EDT 2011

Scott, Arnd,

thanks a lot for your comments and suggestions, much appreciated! :-)


On Thu, Mar 24, 2011 at 10:36 PM, Arnd Bergmann <arnd at> wrote:

> On Thursday 24 March 2011 20:26:05 Christoph Derndorfer wrote:
> > Hi all,
> >
> > the folks from the Austrian pilot project want to equip the XO-1s there
> with
> > SD cards. Are there any restrictions wrt size, speed, etc. that they
> should
> > be aware of when purchasing the SD cards? I'm particularly asking after
> > reading James' mention of seeing more issues with newer cards and the
> XO-1
> > power off bug.
> >
> > Or asked the other way 'round: Are there any particular cards or
> > manufacturers which people can recommend?
> Have a look at my list at
> Stay away from brands that typically have only one writable allocation
> unit, these will be slow and wear out very quickly when formatted with ext3
> or other Linux file systems. Higher is better here, and it's something that
> is usually not reflected in the speed class rating. Also avoid those that
> only
> support linear I/O.
> Sandisk cards tend to be ok (especially the Ultra and Extreme versions),
> Kingston tends to be really bad, most others have somewhat mixed results
> though sometimes the cheapest ones can be really good.
> Class 10 cards are not required to support efficient random I/O, so they
> are
> sometimes slower than Class 6 cards from the same manufacturer.
> If you buy a sample, I'll gladly help you figure out if it's any good
> before
> you buy a lot of them, in return for more data for my survey page ;-).
>        Arnd

Christoph Derndorfer
co-editor, olpcnews
e-mail: christoph at
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