How do you compare an iso file and a burned disk?

Asked by Jarno Suni on 2007-01-21

I am wondering if it is handy way to check equivalence of a general iso file and burned disk?

Question information

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Status:
Solved
For:
Ubuntu Edit question
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Solved by:
williamts99
Solved:
2009-04-13
Last query:
2009-04-13
Last reply:
2007-04-06
Matt Thompson (mattthompson) said : #1

Hi,

All the information you need should be here: https://help.ubuntu.com/community/HowToMD5SUM

If you need any more just ask.

Cheers,

Matt

Matt Thompson (mattthompson) said : #2

Hi again,

If this has solved your problem it would help lots if you could mark your request as solved.

Thanks,

Matt

Jarno Suni (jarnos) said : #3

Well, it solves problem for Ubuntu CDs, but what if I want to check if another CD matches some iso file?

williamts99 (williamts99) said : #4

Same thing, except you would use the md5sum of the 'other' ISO image file.

Matt Thompson (mattthompson) said : #5

You can create an md5 checksum of the iso like this:

md5sum file.iso > file.iso.md5

and you can create an iso using the instructions found here:

http://ubuntuforums.org/showthread.php?t=6509

Make sure that the filename within the file.iso.md5 is the same as the iso file you've just created and then you should be able to check that their the same.

This isn't the most ideal or efficient solution, but it should work.

Cheers,

Matt

Best williamts99 (williamts99) said : #6

Though sometimes CD burning programs add some extra bits at the end of the CD, therefore it is safer to take the md5sum only from the 'original' CD. So it would be better to use the cmp command and not the md5 hash of the burned disk. Because you 'could' get an error regardless of the disk being burned correctly or not.

$ cmp /dev/cdrom /directory/diskimage.iso
cmp: EOF on /directory/diskimage.iso

The EOF on the ISO image means that the CD image is an EXACT copy PLUS padding. If you got an EOF on /mnt/cdrom that would mean the CD was incomplete.

Best Regards,
Williamts99

williamts99 (williamts99) said : #7

Oh yea, I also wanted to add that if you do want to get the md5 hash of a burned disk, just put it into your drive and issue the following command

md5sum /dev/cdrom

That will create an md5 hash of the disk in the drive located at /dev/cdrom.

Jarno Suni (jarnos) said : #8

I tried the cmp mehtod for Ubuntu server CD, but got an error:
cmp: /dev/cdrom: Input/output error

The method told in chapter MD5SUM on CD of https://help.ubuntu.com/community/HowToMD5SUM
i.e. command "md5sum -c md5sum.txt | grep -v 'OK$'" on its mount point
 outputs nothing for the same CD.

Matt Thompson (mattthompson) said : #9

Oops, now I realise that mine wouldn't work. Sorry about that.

Your cd drive might not be at /dev/cdrom.

Insert the cd and then when the drive appears on your desktop go into that and see where it is (eg /media/cdrom )

Now type:

cat /etc/mtab | grep "whatever the location of the cd was"

From that line you can use the bit starting with /dev in the cmp and md5sum methods that williamts99 suggested.

Hope it works for you,

Matt

Jarno Suni (jarnos) said : #10

I get similar error from cmp even if I use the suggested /dev/something. (It does not give the error right away, but after some time.)

mikecoffelt (mikecoffelt) said : #11

can i boot from a iso file without buring to cd the file is on a clean hard drive my burners down and i cant afford a new one right now and i really want to get this up and running im so tired of windows

Jarno Suni (jarnos) said : #12

Maybe you could use a USB flash drive stick to boot an ubuntu revision?

Mackenzie Morgan (maco.m) said : #13

Try this: http://marc.herbert.free.fr/linux/win2linstall.html It lets you install Linux while using Windows.

Jarno Suni (jarnos) said : #14

Thanks williamts99, that solved my question.