Media Check errors on Fedora Core 6

[tom]

On Fri, 27 Oct 2006, Deron Meranda wrote:

> On 10/27/06, Thompson Freeman <tfreeman at intel.digichem.net> wrote:
>> I have downloaded the cd isos for FC-6, and the sha1sums of
>> the images test as good. I have burned to cd two complete
>> sets of cds, and gotten one cd to pass the media check
>> step. _Everything_ else fails, and fails multiple times.
>
> How are you burning the CDs?  It is most likely caused by
> the lookahead buffering used during the write process (or something
> like that, I don't fully understand).
>
> If you're using cdrecord, try adding the options "padsize=63s -pad -dao".
> It has worked for me.  Such as something like:

The solution turned out to be found earlier - run with the ide=nodma 
command line. Everything turns happy then.

>
> $ cdrecord -v padsize=63s -pad -dao dev=ATA:1,1,0 FC-6-i386-disc1.iso
>
>
>> As a side issue, how would I get the sha1sum of the burned
>> cd? I believe that should remain the same as the image
>> file, or am I completely a sea?
>
> I've not found an easy way for this either, as you need to ignore
> any padding bytes at the end (which don't matter).  So it's a
> multistep process where you read the raw bytes from the CD, truncate
> it to the correct length, and then SHA that.  Something like this
> sequence where the CD is read into a file called "x.iso"...
>
> $ readcd dev=ATA:1,1,0 -f x.iso
>
> $ isoinfo -d -i x.iso
> ...
> Logical block size is: 2048
> Volume size is: 346084
>
> $ echo $(( 2048 * 346084 ))
> 708780032
>
> $ dd if=x.iso bs=2048 count=346084 status=noxfer | sha1sum
> cc503d99c9d736af9052904a6ab14931b0850078  -
>
>
Ok. Now that is a little bit ugly. Doable, scriptable, but not pretty. I 
think I'll pass on that idea.

Still, I really appreciate your time to write it out. I will definitely 
save it against future need. Thanks.