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Thread: compare checksums to what?

  1. #1

    Default compare checksums to what?

    I've been reading the FAQs and I'm currently running md5 and sha1 hashes against the downloaded .iso file but what do I compare the outputs to to verify that the downloaded file is complete and uncorrupted?

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    Default Re: compare checksums to what?

    Quote Originally Posted by sassan_attari View Post
    I've been reading the FAQs and I'm currently running md5 and sha1 hashes against the downloaded .iso file but what do I compare the outputs to to verify that the downloaded file is complete and uncorrupted?
    Take a look at this page where it states "Verify your download":
    Software.openSUSE.org

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    Default Re: compare checksums to what?

    BTW, that page could use a sentence or two to say that the checksum program should be run on the ISO file. It seems obvious to us, but I have at least twice seen posters provide a strange result matching no published sum. It transpired that the posters were running the checksum program on the checksum file.

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    Default Re: compare checksums to what?

    Quote Originally Posted by ken_yap View Post
    BTW, that page could use a sentence or two to say that the checksum program should be run on the ISO file. It seems obvious to us, but I have at least twice seen posters provide a strange result matching no published sum. It transpired that the posters were running the checksum program on the checksum file.
    And that should be fine, if they include '-c'

    Code:
    gwb@linux-w12j:~/isos> md5sum -c openSUSE-KDE-LiveCD-Build0577-x86_64.iso.md5
    openSUSE-KDE-LiveCD-Build0577-x86_64.iso: OK
    Use the Source, Luke

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    Default Re: compare checksums to what?

    Yes, but most of the people who need to know about checksum verification aren't running Linux yet, and those who know about md5sum -c are doing fine.

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    Default Re: compare checksums to what?

    The lazy way is the start K3b and point it at an .iso. The first thing it will do is calculate the MD5. You can then Quit if you don't intend to do anything with the .iso immediately.

  7. #7

    Lightbulb Re: compare checksums to what?

    Quote Originally Posted by sassan_attari View Post
    I've been reading the FAQs and I'm currently running md5 and sha1 hashes against the downloaded .iso file but what do I compare the outputs to to verify that the downloaded file is complete and uncorrupted?
    I had the same question. There was no iso.md5 file that I could download mentioned anywhere on the "Verifying your Download" page; in Chrome at least, the link from clicking on "md5" just refreshed the page.

    I stumbled across the Novell FTP from another post on here, and behold:

    Index of /pub/opensuse/distribution/11.2/iso

    Look for the name of the iso you downloaded, and you'll see an iso.md5 file. I opened that in Notepad and it displayed the identical checksum output I received after running md5deep on the .iso file. Make sure you get the right .md5 for yourself; I mistakenly grabbed the wrong checksum file and was dismayed to see a completely different checksum before I realized I grabbed the wrong file.

    Hope that helps!

    If there was a link to Index of /pub/opensuse/distribution/11.2/iso from Software.openSUSE.org that would be cool, because unless I'm missing something, there's absolutely no way for me as a new user to have found that .md5 file without having already been used to digging for information. (and willing to do so because opensuse looks so awesome as a way to learn linux!)

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    Default Re: compare checksums to what?

    gtguy wrote:
    > unless I'm missing something, there's absolutely no way
    > for me as a new user to have found that .md5 file without having already
    > been used to digging for information.


    unfortunately, you are correct..

    i can tell you that there USED to be a link on that page!

    apparently someone tried to improved the page and failed..

    they left links to the MD5 sums for extra languages and non-oss disks
    but NOT to the DVD or Live CDs themselves..

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    Default Re: compare checksums to what?

    DenverD wrote:
    > apparently someone tried to improved the page and failed..


    i have sent a note to both webmaster@opensuse.org and
    http://forums.opensuse.org/community...i-discussions/ on the
    matter....hopefully the broken links will be soon repaired..

    @gtguy: THANKS for posting


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    DenverD (Linux Counter 282315)
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  10. #10

    Default Re: compare checksums to what?

    Quote Originally Posted by DenverD View Post
    @gtguy: THANKS for posting
    Thanks for notifying the admins on that. Checksum and burning question, since this thread is already kind of related:

    I understand the logic behind burning slowly is to reduce the chance of an error that would corrupt the data of the DVD. If I burn the image fast or on cheap media, and the checksum is valid post-burning, does it matter how I burned the DVD? Doesn't that post-burn checksum verification tell me if the burn was successful, or is it possible to get a valid checksum post-burn but still have disc imperfections/errors?

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