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Old 07-21-2011, 07:07 AM   #1
Registered: Dec 2006
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md5sum problem

Hi I did an md5sum on a .raw opensuse image that I downloaded and dumped onto a usb stick.
The checksum for the .raw file and the dumped image on the device /dev/sdg don't match, so I'm wondering if its a mistake or something is altering traffic from my harddisk to my usb stick. The checksums for the Download were correct!

However once transfered from hard drive to usb I got this:
1448cebbfa28f822f54c656ef8adaaeb  Aubreys_GNOME_Reloaded.i686-0.0.10.raw
2a6b3e8fd668433e315aac2cd4836b20  /dev/sdg
Am I making a mistake comparing the .raw md5sum with the usb dump? I followed the instructions on this site:
Old 07-21-2011, 08:22 AM   #2
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Okay, so, this one is officially the weirdest thing today I usually follow other lines, but it boils down to this:

- download the file (an ISO, for example)
- put it somewhere, I have a folder for this...
- copy and paste the md5 string into gedit
- open the console navigate to the downloaded file and enter "md5sum [filename]"
- I get a long string, and
- compare against what it says in gedit

Example output

md5sum microcore-current.iso
d36c9099b7afd83ee7c74c27d5d04c41 microcore-current.iso
Can I tempt you to give my way a whack? I'll follow this thread to see where you end up...



Last edited by ButterflyMelissa; 07-21-2011 at 09:53 AM.
Old 07-21-2011, 09:26 AM   #3
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So you ran md5sum against the file like this

$ md5sum Aubreys_GNOME_Reloaded.i686-0.0.10.raw
Then you wrote Aubreys_GNOME_Reloaded.i686-0.0.10.raw on to the USB stick to create a bootable USB stick.

The you ran md5sum against /dev/sdg like this

$ md5sum /dev/sdg
Is that right? If that's what you did then of course getting different values from md5sum sounds like expected behaviour given that you're running md5sum against different things.
Old 07-24-2011, 06:25 AM   #4
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Actually, you have to compute the md5sum of the first N bytes of /dev/sdg, where N is the size of the original image file. Example:
$ ls -l file.raw
-rw-r--r-- 1 colucix users 1939866112 Feb 15  2010 file.raw
$ dd if=/dev/sdg ibs=1 count=1939866112 | md5sum
3e2e1c757afcb29d25a74c14d1c44fb1  -
$ md5sum file.raw
3e2e1c757afcb29d25a74c14d1c44fb1  file.raw


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