Checking the integrity of a LiveDVD/CD

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Re: Checking the integrity of a LiveDVD/CD

Postby ReemZ » Sun Jan 08, 2012 0:27

Is there a way to do this with a live-usb created with Unetbootin?
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Re: Checking the integrity of a LiveDVD/CD

Postby ReemZ » Sun Jan 08, 2012 3:42

See also Fitz' answer to my problem with abovementioned method of checking burnt disks' integrity.

Fitzcarraldo wrote:(...) the following methods can be used to check the integrity of the burnt LiveDVD/CD:


Method 1
This does not work anymore, this will give a false negative.

Method 2
Haven't checked.

Method 3

Fitzcarraldo wrote:(...) http://www.mepis.org/docs/en/index.php? ... _a_Live_CD (...)

The method for checking the integrity of a LiveCD under Linux, given on the above-mentioned Web page, does not work for me. If I use md5sum /dev/cdrom it does not return the same md5sum as published on the mirrors even though the LiveCD is good. So do not use that method under Linux, use either Method 1 or Method 2 given in this post.

This now seems the way to go about it!

So, in summary:

1. Verify integrity of downloaded iso by comparing the output of md5sum /path/to/file.iso with the hash on the site.
2. Verify integrity of burnt disk by comparing the output of md5sum /dev/cdrom (or whatever your optical drive may be, check your /dev directory) with the hash on the site.

Basically, one command for both the downloaded file and the burnt disk: md5sum.
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Re: Checking the integrity of a LiveDVD/CD

Postby Fitzcarraldo » Thu May 24, 2012 2:28

I'll add the following to my first post to reflect the current situation:

Insert the LiveDVD into the optical drive, let the disc spin up and then enter the following three commands:

Code: Select all
md5sum /dev/cdrom | awk '{print $1}' > md5a.txt
md5sum ~/Sabayon_Linux_8_amd64_K.iso | awk '{print $1}' > md5b.txt
diff -qs md5a.txt md5b.txt

(Obviously change the path and/or the ISO file name to match your circumstances.)

If you get an error message while the md5sum is reading the disc, there must be something wrong either with the burn or with the optical drive itself.

If you get the message "Files md5a.txt and md5b.txt differ" then the burn was bad.

If you get the message "Files md5a.txt and md5b.txt are identical" then the burn was good.
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Re: Checking the integrity of a LiveDVD/CD

Postby totedati » Tue Dec 09, 2014 0:46

you can go even on a deeper level if you want tot check the integrity of a livedvd/cd!

when you bootup from a livedvd medium, be it dvd, cd or usbstick, in that live session the iso image is mounted in /mnt/cdrom:

Code: Select all
[email protected] /mnt/cdrom $ ls -1
autorun.inf
boot
BUILD_INFO
cdupdate.sh
efi
id.2014112915354625999.uefi
isolinux
livecd
livecd.squashfs
livecd.squashfs.sha256
pkglist
qemu
sabayon.bat
sabayon.ico
SecureBoot


here two files is the relevant ones:

    livecd.squashfs
    livecd.squashfs.sha256

and now you can, from the live session, check the integrity of sabayon linux system who is actually packaged inside of iso image:

Code: Select all
cd /mnt/cdrom/
sha256sum -c livecd.squashfs.sha256
livecd.squashfs: OK


when you got the OK is a high chance is all ok with you cd, dvd or usbstick iso image because any other bits errors should be spotted already in the boot phase
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