unable to dd dvd

[Ric Moore]

On 05/01/2013 05:02 AM, Patrick Asselman wrote:
> On 2013-05-01 06:08, JD wrote:
>> On 04/29/2013 04:38 AM, Patrick Asselman wrote:
>>> On 2013-04-28 03:40, JD wrote:
>>>> Tried multiple dvd drives.
>>>> dd if=/dev/sr0 of=dvd.iso bs=2k
>>>> always results  in
>>>> dd: reading `/dev/sr0': Input/output error
>>>> 1+1 records in
>>>> 1+1 records out
>>>>
>>>> Tried on sr1, and sr2  all fail in the same way.
>>>>
>>>> And yet the movie plays just fine with vlc and smplayer!!
>>>>
>>>> This the first time I see this.
>>>> I never had this issue on Fedora.
>>>
>>> Could it be that the DVD is copyrighted and has intentionally corrupt
>>> sectors on it?
>>> The media player simply plays the list of sectors given to it, so it
>>> will never encounter those bad sectors, whereas dd will attempt to
>>> read all sectors, so it will run into problems.
>>>
>>> Best regards,
>>> Patrick Asselman
>>>
>>>
>> What's somewhat interesting is that some movies I buy and back up using
>> dd have no problem at all. And some do, as I stated in my post.
>> I would have thought that all commercial movie dvd's sold in the US
>> follow
>> the same method? policy? of production.
>> But I found a method to get around the problem.
>>
>> Thanx,
>>
>> JD
>
> No, there is a whole ratrace going on between the copyright protectors
> and the people trying to circumvent it. New methods are invented all the
> time, sometimes even leading to problems for people who legally bought
> the copyrighted material (due to standards not being adherred to). This
> is why some producers have now decided to stop trying to protect the
> materials using technical solutions, thus saving money and no longer
> causing nuisance to legitimate customers.
>
> To get some idea about the protection schemes, have a look here:
> http://en.wikipedia.org/wiki/List_of_Compact_Disc_and_DVD_copy_protection_schemes

This was going on back in the Apple ][ days on floppy disks. All sorts 
of schemes, which we learned to thwart. Great fun! All you young people, 
keep up the Good Work! Maybe they will finally tire of the losing 
expenses and give up. :) Ric



-- 
My father, Victor Moore (Vic) used to say:
"There are two Great Sins in the world...
..the Sin of Ignorance, and the Sin of Stupidity.
Only the former may be overcome." R.I.P. Dad.
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