SD card (re-)formatting in Linux

eccerr0r · Posted: Thu Oct 24, 2013 6:20 am Post subject: SD card (re-)formatting in Linux

Well apparently sdcard has a special formatter for Windows/MacOS https://www.sdcard.org/downloads/formatter_4/ -- but of course this is not acceptable for Linux. Anyone took a look at what this formatter program does to SD cards?

I've heard a lot of anecdotal evidence that simply using FORMAT or mkfs has the possibility of shortening the life of SD cards... but doesn't quite make sense to me if wear levelling is working properly...
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smartass · Posted: Thu Oct 24, 2013 7:22 am Post subject:

If the kernel driver exposed the "SD Protected area" in the block device, it could be formatted. So it might be a question of the driver used.

eccerr0r · Posted: Sun Oct 27, 2013 8:52 pm Post subject:

Then there's still the upper layer user software, now is that available somewhere?

I suspect the card readers that show SD cards as simple block devices may have that support missing, but perhaps the ones that show up as mmcblk may have some hope...?
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energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2042 Location: Germany

I have formated a lot of SD cards in card readers or in my camera - and I never used special software or had problems.
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TheLexx · Posted: Sun Oct 27, 2013 10:44 pm Post subject:

eccerr0r · Posted: Mon Oct 28, 2013 3:41 am Post subject:

I haven't had any problems (yet) with the SD readers but wondering what the sdformat utility does in windows that does something "magical"... and whether it can be replicated in Linux.

I've had two SD-class cards fail on me so far:

1 8GB MicroSDHC
1 1GB SD

I don't know what caused them to fail but they are completely unusable - can't write to the root block device anymore with the /dev/sd* readers... I also have an 8GB and a 16GB SDHC cards formatted ext2 that are "so far, so good"...
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Tolstoi · l33t Joined: 20 May 2004 Posts: 670

Just two or three days ago I formatted a SD card on Windows to exFAT as one partition. Taking a look at it under Linux reveales three partitions. WTF?

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2042 Location: Germany

eccerr0r · Posted: Mon Oct 28, 2013 8:44 pm Post subject:

Well we know that SD cards' wear levelling is not nearly as good as a full sized SSD. I'm pretty sure they made some shortcuts to not have to implement an extensive wear levelling system, which then allows them to make the cards cheaper.

I've never tried formatting the card in windows with Format, then again I always have admin rights. That seems to be a security hole if they can work around permissions that way.