On Wed, 2 Feb 2011, Gordan Bobic wrote: > > gordon is right about the SD/MMC card thing, but the "level 10" ones > > can at least guarantee above 10mbytes/sec *read* capability. so > > _yes_ to the SATA interface. > > The 10MB/s is _supposed_ to be for worst-case sequential writes. There > is, however, no defined benchmark, and manufacturers are free to do > their own testing. Most fail any sane real-world measurements of the > specification. > > Just about every SD card I have seen apart from high end Lexar and > SanDisk manage a whopping 1-3 4KB write IOPS. Team Class 10 32GB SD card > is among those. So the class rating is pretty much completely > meaningless for anything except (at most) digital camera use where you > are sequentially writing large files to a FAT32 file system.
I'd suggest you have a look at the work being done by Arnd Bergmann on a new device mapper target to overcome typical SD card misbehavior: https://wiki.linaro.org/WorkingGroups/KernelConsolidation/Projects/FlashDeviceMapper This is based on a survey of card behavior analysis compiled here: https://wiki.linaro.org/WorkingGroups/KernelConsolidation/Projects/FlashCardSurvey Nicolas _______________________________________________ arm mailing list [email protected] https://admin.fedoraproject.org/mailman/listinfo/arm
