On 08/12/17 16:36, Ralph Corderoy wrote:
Hi Peter,
$ sudo dd if=/dev/sdb of=./webiopi3.img
How did you identify it's /dev/sdb?
-- peterm@peterm-MBB-34204H:~$ df
Filesystem 1K-blocks Used Available Use% Mounted on
udev 1941124 0 1941124 0% /dev
tmpfs 392256 6260 385996 2% /run
/dev/sda1 36538648 11259644 23399884 33% /
tmpfs 1961260 304 1960956 1% /dev/shm
tmpfs 5120 8 5112 1% /run/lock
tmpfs 1961260 0 1961260 0% /sys/fs/cgroup
/dev/sda6 113166916 78505556 28889696 74% /home
cgmfs 100 0 100 0% /run/cgmanager/fs
tmpfs 392256 20 392236 1% /run/user/1000
/dev/sdb2 7311888 3960888 2999304 57%
/media/peterm/2f840c69-cecb-4b10-87e4-01b9d28c231c
/dev/sdb1 64456 21304 43152 34% /media/peterm/boot
peterm@peterm-MBB-34204H:~$
dd: error reading '/dev/sdb': Input/output error
That shouldn't happen.
- mounted
Yes, you ideally want to do it unmounted, as you initially tried.
129504+0 records in
129504+0 records out
...
86240+0 records in
86240+0 records out
Looks like there's an intermittent problem reading from the card, or
through the network of USB cables, hubs, etc., to get to it. Can you
plug it in `closer' to the machine, e.g. a built-in card slot?
You could keep repeating it, unmounted, until it succeeds without I/O
error. Or try another PC, even if you `of=/dev/null', to see if that
can read it without error? Or try a card you don't want to image, just
so you know it's possible in theory on that hardware?
This is the closest that I can find to the device:
https://www.amazon.co.uk/Card-Reader-Adapter-Laptop-Computer-Orange/dp/B06XBK9ZHH/ref=sr_1_82_sspa?ie=UTF8&qid=1512752502&sr=8-82-spons&keywords=sd+card+to+usb+adapter&psc=1
I have had it for a few years.
it imaged at 12.1GB from a 16GB disk which does sound a bit large.
Small? 16 GB disk should give 16 GB image, unless you're compressing.
And 16 GB is 14.9 GiB if you're switching units in your measuring.
Another way to check, having removed and re-inserted the card so Linux
has forgotten all about it from its buffer cache, is to take its digest
and that of your image file.
sha1sum /dev/sdb disk.img
They should match. And writing down a prefix of the digest somewhere
means you'll be able to check each hasn't changed in the future.
I'll try that later. Grandchildren should arrive in the next couple of
hours for the weekend.
Thanks for advice.
Cheers, Ralph.
--
Next meeting: Bournemouth, Tuesday, 2018-01-09 20:00
Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/
New thread: mailto:[email protected] / CHECK IF YOU'RE REPLYING
Reporting bugs well: http://goo.gl/4Xue / TO THE LIST OR THE AUTHOR
