Re: [ARSCLIST] Memorex CDs

[steven c <stevenc@xxxxxxxxxxxxxx>]

----- Original Message ----- 
From: "Scott Phillips" <scottp@xxxxxxxxx>
> ...and how do manufacturers like AMD survive? They initially made 'clean
> room' versions of Intel CPU chips, that were to function exactly like
> the Intel chips, but were made by reverse engineering by function alone.
> This avoided the patent and copyright issues with Intel. IF there is a
> reason with enough money behind it, future playing the disks WILL be
> possible, but the form of the player might be entirely unfamiliar to us
> from the viewpoint of our current technology. The idea that a CD, 78, or
> whatever disk could one day be placed on some type of flat bed scanner,
> scanned, and the data processed into the original audio doesn't seem
> very far fetched at all to me personally.....even in my lifetime.
> 
Well, this would be fairly simple with an analog disc record, since
the path of the groove actually mirrors the waveform of the sound
that was recorded. It will be somewhat more complicated for stereo
recordings, since they reflect two different waveforms simultaneously
(this assumes that a way could be found to "read" a vertically
modulated groove or the vertical component of one?). However,
"reading" a CD providing one had enough magnification to
visually identify the pits (or absences thereof) would require
knowing or deducing the algorithm used to translate this into
a sound signal!
>
> Even if the format details were unknown then, a detectable pattern would
> remain, and there are many very bright people out there. The current
> equipment, or examples of them, could provide useful hints about how to
> go about this, even if entirely non-functional. One can't look at the
> mechanics of a CD/DVD transport and miss the fact that a disk placed in
> it clearly was to rotate, and that a beam of light through a lens was to
> shine on it. Further, you can see that the light beam was set up to
> slide from the inside of the disk to the outside (or the other way
> around) This information alone makes the principles involved in how the
> data WAS read pretty clear. After that, it is just how inventive the
> researcher is. 
> 
We can assume that "digital" will clue the party that the pits and
absences represent ones and zeros. The next problem (see above) is
trying to figure out how the sequence (which wouldn't produce
anything like a sound signal if read directly) relates to the
sequence of digital values that represent a stepwise representation
of a sound waveform.
>
> In the end, I wonder if the important thing isn't if the reading device
> is available....only that the data survives intact for someone to
> decode, much as a stone tablet with a 3000 year old text on it. The
> language may be unknown at first, but where there is a will......
> 
Not entirely true...the last I knew there existed many Etruscan
stone tablets that clearly contain messages...but messages in a
language that no one can translate!

Steven C. Barr