Hi all, A friend of mine gives me a copy of Centos5 DVD. I then make an iso of it using dd if=/dev/cdrom of=centos5.iso command. I then check it using sha1sum. But the result is different than of listed in Centos website. Should it the same? Or we simply cannot compare sha1sum from burned DVD to that of 'unburned' iso file? Thanks.
Fajar Priyanto wrote:
Hi all, A friend of mine gives me a copy of Centos5 DVD. I then make an iso of it using dd if=/dev/cdrom of=centos5.iso command. I then check it using sha1sum. But the result is different than of listed in Centos website. Should it the same? Or we simply cannot compare sha1sum from burned DVD to that of 'unburned' iso file? Thanks.
AFAIK, the checksum should be matched on the ISO file pre-burn, against the checksum posted on the server from which the ISO was downloaded. Any differences in hash against the burned media may be due to additional metadata added by the burning engine.
HTH, ~Ray
On Tuesday 20 November 2007 21:49:25 Ray Leventhal wrote:
AFAIK, the checksum should be matched on the ISO file pre-burn, against the checksum posted on the server from which the ISO was downloaded. Any differences in hash against the burned media may be due to additional metadata added by the burning engine.
Thanks Ray, I guess that makes sense.
On Tue, 2007-11-20 at 21:45 +0700, Fajar Priyanto wrote:
A friend of mine gives me a copy of Centos5 DVD. I then make an iso of it using dd if=/dev/cdrom of=centos5.iso command. I then check it using sha1sum. But the result is different than of listed in Centos website. Should it the same? Or we simply cannot compare sha1sum from burned DVD to that of 'unburned' iso file?
isosize (along with dd) is your friend.
Fajar Priyanto wrote:
Hi all, A friend of mine gives me a copy of Centos5 DVD. I then make an iso of it using dd if=/dev/cdrom of=centos5.iso command. I then check it using sha1sum. But the result is different than of listed in Centos website. Should it the same? Or we simply cannot compare sha1sum from burned DVD to that of 'unburned' iso file? Thanks.
an afterthought -
the subject of your mail was md5sum...the body speaks about sha1sum. They're different mechanisms; comparing a sha hash to an md5 will always be different, I believe.
~Ray
On Tue, Nov 20, 2007 at 09:52:43AM -0500, Ray Leventhal wrote:
Fajar Priyanto wrote:
Hi all, A friend of mine gives me a copy of Centos5 DVD. I then make an iso of it using dd if=/dev/cdrom of=centos5.iso command. I then check it using sha1sum. But the result is different than of listed in Centos website. Should it the same? Or we simply cannot compare sha1sum from burned DVD to that of 'unburned' iso file? Thanks.
an afterthought -
the subject of your mail was md5sum...the body speaks about sha1sum. They're different mechanisms; comparing a sha hash to an md5 will always be different, I believe.
definitely!
this and the relevant links might help: http://www.g-loaded.eu/2006/10/07/verify-a-burned-cddvd-image-on-linux/#more...
Cheers,
Tru
On Tuesday 20 November 2007 22:01:44 Tru Huynh wrote:
an afterthought -
the subject of your mail was md5sum...the body speaks about sha1sum. They're different mechanisms; comparing a sha hash to an md5 will always be different, I believe.
Oops.. you're right. My mistake. What I really meant was sha1sum, because from google I found the sha1sum of Centos5 dvd, not md5sum. So, I was comparing the result of sha1sum, not md5sum. Sorry.
When booting on the DVD it will ask you if you want to test it! You know where every body is always selecting SKIP! You can check it this way
On Nov 20, 2007 3:45 PM, Fajar Priyanto fajarpri@cbn.net.id wrote:
Hi all, A friend of mine gives me a copy of Centos5 DVD. I then make an iso of it using dd if=/dev/cdrom of=centos5.iso command. I then check it using sha1sum. But the result is different than of listed in Centos website. Should it the same? Or we simply cannot compare sha1sum from burned DVD to that of 'unburned' iso file? Thanks. -- Fajar Priyanto | Reg'd Linux User #327841 | Linux tutorial http://linux2.arinet.org 21:45:18 up 2:09, 2.6.22-14-generic GNU/Linux Let's use OpenOffice. http://www.openoffice.org The real challenge of teaching is getting your students motivated to learn.
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
On Tue, Nov 20, 2007 at 04:15:53PM +0100, Alain Spineux wrote:
When booting on the DVD it will ask you if you want to test it! You know where every body is always selecting SKIP! You can check it this way
that check will only tell you is the embedded checksum is ok (correct/complete transfer/burn from iso -> dvd), not if the dvd is a "genuine" CentOS version (unmodified). AFAIK, you have to check against the md5sums...
my .02 cents
Cheers,
Tru
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Alain Spineux -
Fajar Priyanto -
Ignacio Vazquez-Abrams -
Ray Leventhal -
Tru Huynh