home | list info | list archive | date index | thread index

Re: [OCLUG-Tech] how to determine the *usable* size of an SD card?

  • Subject: Re: [OCLUG-Tech] how to determine the *usable* size of an SD card?
  • From: "Robert P. J. Day" <rpjday [ at ] crashcourse [ dot ] ca>
  • Date: Thu, 19 Jan 2012 15:02:41 -0500 (EST)
On Thu, 19 Jan 2012, Singer X.J. Wang wrote:

> That's a deviation of less then 0.5%.. that's not that bad in most industries..
>
> S
>
> On Thu, Jan 19, 2012 at 14:48, Robert P. J. Day <rpjday [ at ] crashcourse [ dot ] ca> wrote:
>
>        over the last day on the beagleboard list, there was an animated
>       discussion that touched on the fact that some "dd" copies to SD cards
>       was failing since the actual capacity of the SD card was noticeably
>       less than advertised.  as in, trying to write a 4G image to an
>       allegedly 4G SD card failed, "no space left on device".
>
>        is there a utility in linux that will tell me that *real* capacity
>       of an SD card if i pop it into the SD slot?  if i write an image to an
>       allegedly 8G micro SD card and pop it into my beagleboard, and stop in
>       u-boot, what i can do is:
>
>       # mmcinfo
>       Device: OMAP SD/MMC
>       Manufacturer ID: 27
>       OEM: 5048
>       Name: SD08G
>       Tran Speed: 25000000
>       Rd Block Len: 512
>       SD version 2.0
>       High Capacity: Yes
>       Capacity: 7969177600     <--- AHA!
>       Bus Width: 4-bit
>       #
>
>        that's *clearly* less than a true 8G.  is there a way to see that in
>       linux?  thanks.

  huh?  8G is officially 8589934592.  the value above is a full 8%
smaller.

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================