Comments on: MicroSD card FAQ

By: Episode 065 – Mat’s new Lack Rack : Sunday Morning Linux Review

Episode 065 – Mat’s new Lack Rack : Sunday Morning Linux Review — Sun, 06 Jan 2013 16:31:22 +0000

[...] –Theodore Ts’o And here is a link to the information he is referring to: http://www.bunniestudios.com/blog/?p=2297 [...]

By: Sami Lehtinen

Sami Lehtinen — Mon, 31 Dec 2012 11:58:58 +0000

Low voltage test is missing. On battery powered devices some cards get always corrupted when voltage drops.

Been there, done that.

By: advaneil

advaneil — Thu, 23 Aug 2012 09:33:08 +0000

A very helpful post which helped me a lot as I have make a project on micro SD cards.This post gave enough material to understand the micro SD cards clearly.

By: Testing a new SD card under linux | tüfteln

Testing a new SD card under linux | tüfteln — Tue, 15 May 2012 10:32:43 +0000

[...] are simply bad ones initially removed from production that are resold afterwards by third parties. Bunnie has an excellent article on fake SD cards and how to test them. For more info on SD cards, check out this flash card [...]

By: Arnd Bergmann

Arnd Bergmann — Sun, 29 Apr 2012 10:02:40 +0000

Thanks for Linking to my LWN article, I hope that will be useful to other people who stumble upon this page. I also maintain a list of devices at https://wiki.linaro.org/WorkingGroups/Kernel/Projects/FlashCardSurvey and a tool that can find out the characteristics of most cards, which is linked from there, and from the laptop.org wiki that Martin Langhoff pointed to above. This database also has a list of the manufacturer ID values you can expect to see from a lot of vendors.

Testing with “./flashbench –open-au –open-au-nr=5 –random –blocksize=4096 –erasesize=-4194304} /dev/mmcblk0″ as Martin does generally tells you if a card is any good. E.g. all Kingston cards will have very low results for small block sizes there (a few kb/s), while decent cards like current Samsung models or most Sandisk cards can reach close to the maximum throughput with smaller sizes, too, which is what you need when you have a Linux file system like ext4 (never use ext3 on SD cards please) or btrfs.

Feel free to contact me if you have questions about interpreting flashbench results.