On Wed, 3 May 2000 SonofWashu@aol.com wrote:
> The region coding is not the only locks placed on DVDs, however, there
> are a number of others used in special instances, including one to
> blank out the screen and sound (though, not always both) if the machine
> is running through another recording device (don't ask me how it knows,
> it just bloody does).

Its called macrovision, its been around since the 80s. Youll find it on
most disney VHS tapes. FWIW macrovision isnt encoded on the DVD, its
actually generated by the DVD player itself.

It doesnt blank out the screen. It messes it up.

>         As far as the self-destructing CD thing goes, why do you think they 
> made them un-cased and totally breakable?  The original idea was, they'd be 
> so cheap it would ruin the industry once they replaced audiotape (this being
> way the hell back, nearly the seventies, when people thought of CDs as some
> for the future), so they were designed in a way that it was likely they'd be 
> busted, scratched, or what have you, and have to be replaced.

Wrong.

CDs are a *giant* leap over vinyl and tape. CDs are *far* less prone to
damage, and *far* easier to repair. You get a scratch on vinyl, you are
screwed. You stretch or break tape, you are screwed.

You scratch a CD, with luck you can polish it out.

The reliablity of CD media is exactly why NASA archives their data on it,
and why they are copying old tapes to CD before the tapes degrade further.

> Some companies have, in the last few years, started making their CDs
> stronger actually, but this is rare, and more often we're getting
> weaker materials, and cheaper recordings.

Totally untrue.

CDs are made of polycarbonate plastic, the same thing used in bulletproof
glass. The physical composition of CDs has changed little since they were
first introduced in the 80s. In fact many of the manufacturing tricks
learned in CD manufacture were later rolled back to improve laserdisc
manufacture. What *has* changed significantly about CDs since the 80s is
better premastering and better QC over the manufacturing process.

-Dan