Helping people with computers... one answer at a time.
There are a lot of differences in the quality of CD/DVD drives and their ability to recover data from a disc.
I was wondering why some drives fail to read a disc when others have no problem. While watching a regular DVD on my TV, it kept skipping. Even after squirting the drive with compressed air and wiping the disc clean with Monster Screen clean, the disc still failed to stop skipping. I then finished watching it on my computer's CD/DVD combo drive/burner with no problems at all. Good thing since the disc is out of warranty as it took too long to watch three years of the Greatest American Hero. All other DVDs on my player do not skip. By the way, most of my DVDs are TV shows. What does someone do if they scratch disc five in an eight disc set and they don't want to re-buy the entire set for one disc or buy used?
In this excerpt from Answercast #46, I look at why CDs and DVDs might not play in a certain player and problems around making backups.
As it turns out, CDs and DVDs are fairly sensitive to a number of different factors that we normally don't need to think about.
Things like the calibration or the accuracy of the laser in the reading device.
The same for the calibration and the accuracy of the laser that was used to create the DVD, if it's a read/writable one that was created in a PC.
It's also the case where some lasers are simply better than others.
Some DVD drives that do the reading are simply better than others and able to tolerate a higher level of error in the data.
The data actually is encoded in such a way so that a certain amount of problems can be recovered from. But, of course, there is a point of no return. There is a point where things get bad enough that it doesn't really help and it's not possible to recover.
But yes, bottom line:
Some CD/DVD drives and readers are simply better than others;
Some CDs and DVDs are simply manufactured better than others;
And some CD and DVD material (the blank DVDs or the raw, unburned material) is often better than others.
So a number of things can come into play that end up resulting in exactly what you see.
Now, the real question is what happens if you lose CD #5 out of an eight CD set (or you know, DVD #5 out of an eight DVD set)?
Unfortunately, there's no real answer to that. It's very much like having a three-volume printed book set and losing the second volume. There really are no options for replacing that volume other than what you've described:
Either ordering a completely new set;
Or finding a volume on a secondary market; or what have you.
Now, the interesting thing with CDs and DVDs is that we have the technology to quickly make copies of them. Whether or not that's legal is where things come into play.
With that caveat out of the way, it's my understanding that:
Even copying a DVD for personal backup purposes (in other words, a DVD that you own);
Because it involves decrypting the encrypted data on that DVD... that's actually a violation of some law somewhere.
I personally don't think that's right. I certainly believe that individuals should – as consumers who have already purchased the DVD (in order to avoid the exact scenario that you're describing) – be able to make personal copies.
So, I will leave it to you and your conscience (and in fact, the laws wherever you happen to live because it does vary from country to country) to be your guide as to what steps you might want to take (or not) to proactively prevent this from becoming a problem at some point in the future.
But those are the solutions:
Pretend it's a paper book.
You can't copy it beforehand (it's just not worth the effort of copying a paper book);
So if you lose the second volume of a three volume series, you're kinda-sorta out of luck.
The way the things are structured right now:
The fact that we have the technology to make a backup copy starts walking us
into this grey area of what is legal or not; what is ethical or not; and to
some degree, what is moral or not. So, that's the best I can offer you
End of Answercast #46 Back to – Audio Segment
Comments on this entry are closed.
If you have a question, start by using the search box up at the top of the page - there's a very good chance that your question has already been answered on Ask Leo!.
If you don't find your answer, head out to http://askleo.com/ask to ask your question.