[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: checking integrity of already written CD/DVD more info

On 2009-04-01_10:34:41, Matus UHLAR - fantomas wrote:
> On 31.03.09 12:57, Paul E Condon wrote:
> > I did an experiment with the drive that always truncated the dd read
> > of the CD. The iso is lenny business card. This iso is 18133 blocks
> > of 2048 bytes each. The read back using dd on the short read drive
> > is 18104 2kblocks long, which is 29 block short of a full load.
> [...]
> > I think this is good news for people who are unlucky enough to have
> > only disk drives that give too short a read-back from a CD. 
> shouldn't they replace their CD/DVD drives instead?
> -- 
> Matus UHLAR 

Everyone should replace their hardware whenever a new model becomes
available, but some of us are slackers at supporting the world
economy.  ;-)

The drives are serviceable for reading and burning CD/DVDs, just not
so good at reading to EOF. The iso standard defines a format for data
on disk that tells the reading software where exactly every datum
is. In normal operation there is never any need to test for EOF.

Maybe the reason that there is no confusion in more modern hardware is
that there is only one factory left in the world actually making these
drives, so there is de-facto consensus on how they should operate.

Paul E Condon           

Reply to: