short-changed on SD card?

Warren Block wblock at wonkity.com
Mon Feb 2 12:29:08 PST 2009


On Mon, 2 Feb 2009, William Bulley wrote:

> Thanks.  According to the newfs(8) man page it is used only for BSD
> style file systems (ufs and ufs2).

newfs_msdos(8)

>  I am okay with the FAT16 formatted
> SD card, I'm just upset that I paid for a 2.0 GB card and ended up with
> what seems to be a 1.0 GB card.  I would be happy if I could make the
> SD card look like this:
>
>   slice 1  2.0 GB (well, 1920 MB if you insist)
>   slice 2  <UNUSED>
>   slice 3  <UNUSED>
>   slice 4  <UNUSED>

It's generally not useful to slice/partition a small SD card.  Without a 
slice table, the whole device is just one slice.

Offhand I don't know if you can overwrite an existing slice table (boot 
block) with just a 'newfs_msdos /dev/da1'.  Probably.

If not, you can just 'dd if=/dev/zero of=/dev/da1 bs=512 cnt=1' and then 
do the newfs_msdos.

If you plan to use that card in a camera, you are a little safer doing a 
"full" or "low-level" format with the card in the camera.  Some cameras 
create and like not-quite-right filesystems.  Older Canon cameras, for 
instance.

Finally, there are more than a few reports of SD cards with false 
capacities bought on ebay.

-Warren Block * Rapid City, South Dakota USA


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