Is there a recommended class of microSD card for the Beagleboard and
Beaglebone? Class 4? Class 6? Class 10?
SD by default coming on Beagleboard is Class 4. And it is the same for Beaglebone.
Al 13/03/12 13:28, En/na steve ha escrit:
There's a good review written by Steve here:
http://www.sakoman.com/OMAP/microsd-card-perfomance-test-results.html
Regards,
If you're doing any sort of Android work don't even try anything but the best Class 10 you can get your hands on.
We offer known-good Class 10 microSD cards
https://specialcomp.com/beagleboard/bone.htm
Special Computing
I've personally found the SanDisk Ultra Mobil micro SD cards to be fairly good. They're only rated class 6 but perform better than some class 10 cards I've seen. The 4GB version should be slightly more capable than the 8GB version due to number of open simultaneous erase blocks and smaller assumed erase block sizing.
My flashbench results for each:
4GB: http://lists.linaro.org/pipermail/flashbench-results/2012-February/000256.html
8GB: http://lists.linaro.org/pipermail/flashbench-results/2011-December/000240.html
The Kingston cards are generally poor performers in regards to number of simultaneous open erase blocks. Even the class 10 ones:
http://lists.linaro.org/pipermail/flashbench-results/2012-February/000253.html
http://lists.linaro.org/pipermail/flashbench-results/2012-February/000252.html
The Linaro list is useful:
https://wiki.linaro.org/WorkingGroups/Kernel/Projects/FlashCardSurvey?action=show&redirect=WorkingGroups%2FKernelConsolidation%2FProjects%2FFlashCardSurvey
-Andrew
Wow, thanks for all the links. This is pretty useful stuff.
Indeed, the criteria isn't the Class but the actual performance. Unfortunately I've found the lower classes to have dismal performance. But you are right, there are exceptions.
Cheers,
By blind experiment I found class does matter, but unfortunately I did
not clearly document this. Here's from my writeup:
"I used the HP formatter version 2.0.6 (SP27608) to make the SD card
FAT, instead of FAT32, which did not work when used several times
previously to burn an image.
A Maxell low-speed microSD card I bought at Wegmans worked, sometimes,
but did not work reliably. So I bought a Dane-Elec microSD, high speed
card (labeled MicroSD HC 4 High Speed), wrote the image, and it worked
just like the original. Booted fast, etc. That one was around $13 at
Target, and came with a handy USB dongle it plugged into to become
just like a USB flash drive..."
I did note that writing the image to the presumed low speed card went
at about 1/2 the speed of the presumed class 4 Maxell (2.5 MB/s vs 5
MB/s.)
Oops, error in last paragraph. The Maxell is the low speed (2.5 MB/s)
card, the Dane-Elecmicro is the higher one. ANd, The lower speed one
really only worked rarely.