Re: [ARSCLIST] Gold CDs

[Don Cox <doncox@xxxxxxxxxxxxxx>]

On 25/09/04, George Brock-Nannestad wrote:

>> Books several centuries old are still in good condition today, with
>> no
>> loss of information. So perhaps an expected life of 400 years or
>> more in
>> dry storage?
>>
>> The real question is how valid accelerated aging tests are.
>>
>> A particular problem with digital media is the constant change in
>> materials and manufacturing methods.
>

> So, I must insist: the real question is "do we have an assurance that
> whatever we store will have a proper machine just waiting to read it".
> I request transparency, i.e. the information out must be identical to
> the information originally put in. So, not only do we need
> mechanical-optical equipment that will get a signal off the media, but
> we also need code conversion equipment that will convert the signal
> off the disc to something we can use, and with the correct clock
> frequency.

The paper documentation of the Red Book CD format should last as long as
any other printed matter.


> Now, if we take the same view of the thousands of transistors that go
> into a modern CD player we quickly come up against a physical barrier:
> the player has to be so large, because of this huge number of
> individual transistors, that the signal transmission time from one end
> to the other becomes considerable, and the player will only be able to
> work with a low clock frequency. So, the output of this reliable
> player will be considerably slowed down and will have to be speeded up
> at the output. This, by the way, may well be the only way that we can
> build a CD player from scratch when we hit upon a cache of surviving
> CDs.

There is no particular reason to suppose that integrated circuits will
get less sophisticated than they are now, barring as I said a social
catastrophe (nuclear war etc).

You do know about FPGAs ?
>
> If you cannot provide the machine, forget about the media.

Well, making a pickup cartridge for LPs from a zero start is also very
difficult. So is adjusting and repairing a mechanism for Welte-Mignon
rolls. Any sound recording needs engineering skills for replay.

Regards
--
Don Cox
doncox@xxxxxxxxxxxxxx