Re: [ARSCLIST] Memorex CDs

[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.

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. 

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......



-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx] On Behalf Of Don Cox
Sent: Saturday, January 14, 2006 7:19 AM
To: ARSCLIST@xxxxxxxxxxxxxxxx
Subject: Re: [ARSCLIST] Memorex CDs

On 14/01/06, steven c wrote:

> Even if a microscope of high enough power was used, all that would be 
> visible are the pits in the surface...and any information they carry 
> can only be accessed by taking the apparent information and applying a

> computer algorithm to it, but only the CORRECT such algorithm.

The coding and error correction used in CDs is well documented.
 
> This is something like trying to figure out how a software program 
> works by looking at the ones and zeroes that make up the program file 
> (and that is only one of several files that operate together to 
> accomplish any tasks!) without knowing the details of the machine 
> language of the computer that ran it...

But we do know.

Regards
--
Don Cox
doncox@xxxxxxxxxxxxxx