Re: [Gumstix-users] MicroSD card reliability

[Chris D. <chr...@gm...>]

Check this out if you've not seen it already:
http://sakoman.com/OMAP/microsd-card-perfomance-test-results.html

It doesn't speak to reliability specifically, but it does go into
performance, classes, etc.

Chris

On Fri, Feb 17, 2012 at 12:03 PM, Mark Zieg <mar...@oc...>wrote:

>  Hi all,
>
>  I've had a number of reliability issues with the "Gumstix"-branded 8GB
> MicroSD cards we received with our Overo Fire / Chestnut43 / LCD EVM packs (
> kit0033 <https://www.gumstix.com/store/product_info.php?products_id=253>).
>
>  I was able to partition, format, and populate one card with a FAT boot
> image and ext3 root filesystem (Ubuntu 10.04 per guide1<http://gumstix.org/create-a-bootable-microsd-card.html>
>  and guide2<http://kfuresearch.wordpress.com/2011/08/05/installing-ubuntu-and-ros-on-the-gumstix-overo-fire/>).
>  Since the first card worked so well, and stood up to regular testing over
> a 3-week development cycle, I didn't worry too much about reproducibility
> problems.
>
>  However, when I copy my final working image to other cards via
> instructions like these <http://wiki.gumstix.org/index.php?title=MicroSd>,
> I found that cards which were duplicated and bootable and testable last
> night, no longer wanted to boot this morning (nothing changed, or was
> moved, or replugged, or anything in my workbench).  Recopying them (this
> time, through a Dynex MicroSD adapter connected through an external powered
> hub, just for variety) had them up and running just fine -- yet I'm nervous
> about how long they may *stay* running (2 of these cards had been copied
> and tested a week ago, so this is the second time they apparently "lost
> tone").
>
>  I've also picked up some PNY cards from Best Buy for testing (2GB, 4GB
> class 4, and 8GB class 10 "Professional"), in case one of those perform
> better than the ones shipped by Gumstix.
>
>  My questions to the list are these:
>
>  1. Is there a brand of MicroSD card which has been found more reliable
> than others?  I value reliability far above performance, or storage, for
> this application.
>
>  2. My understanding is that many SD card vendors simply re-brand over a
> common manufacturer, so any answer to #1 would depend on whether the
> rebranded version came consistently from the same, reliable manufacturer.
>
>  3. Is there a particular size card which works better than others?  I've
> seen notes that sometimes smaller, older 2GB cards work better than the
> newer, faster, higher-capacity cards, precisely because they work more
> slowly.
>
>  4. Is there a particular "class" of card which people have found to work
> better?
>
>  Unfortunately, my experience to date more-or-less agrees with
> Microsoft's rather pessimistic assessment:
>
>  The issue, apparently, is the micro-SD card format. The cards are
> unreliable and inconsistent, even between batches made by the same
> manufacturer, and in Microsoft’s tests, there was no way to “certify” that
> any would work properly. “Even with high end cards, we have seen wild
> differences in IO and performance,” he said. “There is just no
> standardization there.” Put simply, if you expand the storage in a
> compatible Windows Phone device, it may work, and it may not.
>
> “In most cases, users *will* have issues,” he told me. “Most cards are of
> poor quality, and there’s no way we can control that or recommend a certain
> type of card. If you happen to get a good card, with the right performance
> and IO characteristics, it will work reliably. But even a bad card will
> appear to work at first, and the device will boot.”  That, of course, is
> where the fun starts. If you have a bad card, you’ll notice horrible,
> unreliable performance, slow app boot times and performance, lock-ups, and
> random reboots.
>
> http://windowsphonesecrets.com/2010/10/29/microsoft-speaks-on-micro-sd-and-windows-phone-storage-expansion/
>
>
>  Thanks for any advice you can share,
>
>  Mark Zieg
> Ocean Optics OEM
>
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