checking sh1asum of Fedora Core 6 Installation DVD without boot

[Paul Howarth]

Mark Ryden wrote:
> Hello,
> 
> I wonder if there is a way to check the
> sha1sum of Fedora Installation DVD without booting and using
> the mediacheck of the FC6 installer program?
> 
> I know that the iso I downloaded had correct sha1sum.
> 
> But I want to verify that the media I burned also
> has a correct sha1sum without rebooting and starting the medaicheck of
> the installer.
> 
> /dev/hdd in my device (the DVD).
> So I tried "sha1sum /dev/hdd" (I tried twice: when /dev/hdd was not
> mounted and when it was mounted) but the result I got was different from
> what is in the official FC6 sh1sum page.
> 
> Also I tried dumping the iso to disk from the CD drive
> thus:
> dd if=/dev/hdd of=/work/FC6dvd.iso
> and than ran "sha1sum /work/FC6dvd.iso" but again I got the same result
> as in "sha1sum /dev/hdd" before  , which is ***NOT*** what is on the web 
> page.
> 
> I assume that the iso on the media was burned correctly because
> others installed from it.
> 
> However,  is it possible somehow to perform sh1sum correctly on a media
> DVD?

What is the length of the /work/FC6dvd.iso file? Is it the i386, x86_64, 
or ppc version?

Your file may have extra bytes appended to the end of it because the 
kernel does not detect the end of the written data (this is what causes 
mediacheck errors in the first place). This extra data causes the 
checksum to be calculated incorrectly, but you can truncate the file to 
the same as the original size and then the checksum should be OK.

Paul.