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Thread: How to securely erase from usb & flash drves in

  1. #11
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    Default Re: How to securely erase from usb & flash drves in

    On 2013-12-10 17:46, mike7757 wrote:

    > I don't know anything about konsole or terminal, so let's leave that one
    > out for the moment.


    Dunno. I only know the terminal way, as told here.

    --
    Cheers / Saludos,

    Carlos E. R.
    (from 12.3 x86_64 "Dartmouth" at Telcontar)

  2. #12
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    Default Re: How to securely erase from usb & flash drves in

    A single pass should be enough for flash memory. Some methods use multiple passes because magnetic media leaks info to between tracks. But multiple passes could be detrimental to flash because of the ware factor. Also memory sticks do ot have the sophisticated algorithms to level ware and do not have an abundance (or any) of the extra memory as in a ssd. Thus they have much shorter lives by definition.

  3. #13
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    Default Re: How to securely erase from usb & flash drves in

    Quote Originally Posted by robin_listas View Post
    On 2013-12-09 21:56, ken300 wrote:

    There are many ways.

    You can just fill the device with zeros:

    Code:
    cp /dev/zero /dev/device_name
    This is the one that I would like to learn. I could probably do the most of it, but I don't know how to find the device name.
    Mike

    AMD Athlon(tm) II X3 435 Processor, (RAM): 8.0 GiB, openSUSE Leap 42.2, (x86_64)
    KDE: 4.10, ATI Radeon HD Graphics

  4. #14
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    Default Re: How to securely erase from usb & flash drves in

    Put the device in and then in a konsole type mount

    that will list all mounted devices you should be able to see the devices for the stick you put in by the name of the stick

    Note that is will give a partition location so for the device drop the last number

    ie sdc1 is mounted but the device is sdc the one is a partition number

  5. #15

    Default Re: How to securely erase from usb & flash drves in

    Quote Originally Posted by robin_listas View Post
    Probably not.
    OK, thanks.
    Also memory sticks do ot have the sophisticated algorithms to level ware
    That seems to depend on the manufacturer, see .eg. Which USB flash drives use static wear levelling? - The Corsair Support Forums Lenwolf

  6. #16
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    Default Re: How to securely erase from usb & flash drves in

    It is not something I'd count on. Also Id expect those sticks to sell at a premium

  7. #17

    Default Re: How to securely erase from usb & flash drves in

    Quote Originally Posted by mike7757 View Post
    This is the one that I would like to learn. I could probably do the most of it, but I don't know how to find the device name.
    Hi, do
    Code:
     mount >~/before.txt
    before you plug in the device. Then plug it in.
    Now do
    Code:
     
    mount >~/after.txt 
    diff ~/before.txt ~/after.txt
    which will show you which device you plugged in.
    HTH
    Lenwolf

  8. #18

    Default Re: How to securely erase from usb & flash drves in

    Just to say thanks for all those who replied to my initial question, after some messing about i've come to the conclusion that the terminal command:

    dd if=/dev/zero of=/path/to/mounted/filesystem/file.tmp

    works exactly as i want - thanks hendersj

    I had an issue where it was saying the card was full even though it wasn't and then the CPU racing away at 100%, and then i realised that the card was 8gb and in FAT the files can't be any more than 4gb-ish, Once i'd twigged that it went perfectly - Doh!!!!

  9. #19
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    Default Re: How to securely erase from usb & flash drves in

    On 2013-12-11 04:46, mike7757 wrote:

    > This is the one that I would like to learn. I could probably do the most
    > of it, but I don't know how to find the device name.


    Well, again, many ways. :-)

    For instance, you open a terminal and run:

    Code:
    sudo tailf /var/log/messages
    then you plug in the device (if it is connected, umount, remove, connect
    again). You will see in the text that gets printed in the terminal the
    device name.

    Or instead of that command in the terminal, you run, after connect,
    "dmesg" in a terminal. The text is long, but the end of it should be the
    same messages.


    --
    Cheers / Saludos,

    Carlos E. R.
    (from 12.3 x86_64 "Dartmouth" at Telcontar)

  10. #20
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    Default Re: How to securely erase from usb & flash drves in

    On 2013-12-11 13:36, ken300 wrote:

    > I had an issue where it was saying the card was full even though it
    > wasn't and then the CPU racing away at 100%, and then i realised that
    > the card was 8gb and in FAT the files can't be any more than 4gb-ish,
    > Once i'd twigged that it went perfectly - Doh!!!!


    Ah, just write two or three files, different names, that's all.

    --
    Cheers / Saludos,

    Carlos E. R.
    (from 12.3 x86_64 "Dartmouth" at Telcontar)

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