At TS we just had to reject a batch of around 500 flash devices we ordered
because they weren't passing our stress tests. I don't think they were
counterfeit but just of extremely low quality. The industry is adopting "TLC"
tri-level cell flash at an increasing rate which is just extremely unreliable.
We have definitely found the quality of SD flash is deteriorating and we just
released some software to address some of this on the TS-7520:
http://www.embeddedarm.com/about/resource.php?item=628
As part of the above described "DoubleStore" software layer, we have created
our own stress test that is much better than the utilities currently available
on the internet as they work underneath the filesystem layer rather than
through it. New TS-7520's ship with a "sdctl" binary that has a "--stresstest"
option that repeatedly writes/verifies sectors at a block layer. We have a
long term test about 50 boards and 50 SD cards running right now. The cards
that have survive the longest seem to be cards that were manufactured several
years ago. We have a 2007 512MB Sandisk that has been running for over a month
now writing continuously at 4MByte/sec with 0 glitches)
//Jesse Off
--- In "jeffs7283" <> wrote:
>
> It appears your SD card has probably lost too many sectors. Go get a brand
> new 2G SD card and try again. Also there is a utility that you might be
> interested in: http://oss.digirati.com.br/f3/ This is a utility to test SD
> cards and in particular tests them to see if they are counterfeits.
> Unfortunately counterfeiting is rampant in these things, and the "no space
> left on device" error can be symptomatic of a counterfeit device. Always
> purchase SD or microSD cards from reputable sources, and be sure to run the
> F3 utility on any new or unknown cards to be sure they really are what they
> say they are.
>
> --- In "drex459" <dexterjagula@> wrote:
> >
> > Thanks for the help Jeff!
> >
> > I'm not quite out of the woods just yet.
> >
> > I first used gunzip to unzip the file (2gbsd-latest.dd.gz), as you
> > suggested, which left me with '2gbsd-latest.dd'.
> > Then I used: "sudo dd if=2gbsd-latest.dd of=/dev/sdb bs=32k" (and also
> > without the "bs=32k").
> >
> > But I keep getting the message: dd: writing to `/dev/sdb': No space left on
> > device
> >
> > It is a 2GB micro-SD card, and this image from TS suggests it is meant for
> > that size card, so I'm not sure why it's not working. Thoughts?
> >
> > Thanks!
> >
> >
> > --- In "jeffs7283" <jeffs@> wrote:
> > >
> > >
> > >
> > > --- In "drex459" <dexterjagula@> wrote:
> > > >
> > > > I'm pretty new to working in UNIX, and have to do some development on
> > > > the TS-8390-4700 board. Before I get started I have to use an image
> > > > provided by TS. I need some help backing-up an existing micro SD card,
> > > > and "dropping" an imagine onto the same micro-SD card.
> > > >
> > > > Here is a summary of what I have to do:
> > > > 1. Back-up the existing micro-SD card (that came with the TS-8390-4700
> > > > board).
> > > > 2. "Drop" a downloaded image onto the micro-SD card.
> > > > 3. If necessary, how to revert the micro-SD card to the backed-up image.
> > > >
> > > > Here's where I am, and what I still have to do:
> > > > 1. Using the "sudo fdisk -l" command, I was able to see that the
> > > > micro-SD card had a few partitions on it (/dev/sdb1, /dev/sdb2,
> > > > /dev/sdb3, /dev/sdb4). I then used the command "sudo dd if=/dev/sdb
> > > > of=sd.iso", which returned the following result:
> > > > 3862528+0 records in
> > > > 3862528+0 records out
> > > > 1977614336 bytes (2.0 GB) copied, 505.756 s, 3.9 MB/s
> > > > which looks like it got backed-up successfully to the .iso file. Is
> > > > this the best way to back-up/image the micro-SD card, so that I can
> > > > revert ALL files and partitions to the way it was?
> > > >
> > > > 2. The image I require is:
> > > > "ftp://ftp.embeddedarm.com/ts-socket-macrocontrollers/ts-4800-linux/binaries/ts-images/2gbsd-latest.dd.gz";
> > > > Once downloaded, how can I extract this image and "drop" it on the
> > > > micro-SD card? Can I use the 'dd' utility to do this? Or some other
> > > > utility? Do I have to format the micro-SD card first?
> > > >
> > > > 3. If I want to revert the micro-SD card back to the way it was before
> > > > I "dropped" the image onto it, how do I do that using the .iso type (or
> > > > any file type) using the 'dd' utility?
> > > >
> > > > These questions may seem basic, but any help would be greatly
> > > > appreciated! Thanks in advance!
> > > >
> > >
> > > So far I think you've got it. 'dd' is the right utility for doing
> > > straight binary copy from one file/device to another. Since your card is
> > > showing up on /dev/sdb, after step 1 above you now have the original card
> > > image backed up in the sd.iso file. This includes the MBR on the card
> > > and can be used to restore the card image by using dd again in exactly
> > > the same way: "dd if=sd.iso of=/dev/sdb bs=32k" Setting the block size
> > > to 32k is a performance enhancer when writing to the card.
> > >
> > > For (2), writing a downloaded image to the card, you must first gunzip
> > > the downloaded file. Also note that you need to match the SD card size
> > > to the image. Don't try to put an 8Gb image on a 2 gig card and vice
> > > versa. Then it's just "dd if=<downloaded unzipped image> of=/dev/sdb
> > > bs=32k" to load it on the card. Note that it takes a loooooong time to
> > > write to an SD card this way, so be patient. Since you are writing a
> > > complete filesystem image to the card including the MBR there is no
> > > formatting necessary. Just plug in a card and go.
> > >
> > > For (3) see step one above, just write your original sd.iso image back
> > > onto the card with dd.
> > >
> > > Things to remember:
> > >
> > > dd is a very low level operation, no formatting or partitioning of a card
> > > is necessary to use it.
> > >
> > > Use the block size (bs=32k) parameter to improve performance when writing
> > > to sd cards. Leave this off when saving image from the card to disk.
> > >
> > > Match downloaded binary image size to card size. Note that the
> > > downloaded binary image is usually about 10% smaller than the size of the
> > > card in order to allow for the size of the card to shrink slightly over
> > > time due to sectors wearing out.
> > >
> > > Be sure to unzip downloaded images prior to writing to SD card.
> > >
> > > -Jeff
> > >
> >
>
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