Re: [ARSCLIST] Gold CDs

[George Brock-Nannestad <pattac@xxxxxxxx>]

From: Patent Tactics, George Brock-Nannestad

Don Cox wrote:

> On 24/09/04, Peter@xxxxxxxxxxxxx wrote:
>
> > ....................... Oh well, a consensus on what archival means
> > when referring to media would be really nice and I'm certainly open to
> > any suggestions on how we all could get such a definition into a
> > published standard. Any ideas?
>
> I would suggest the printed book as a model.
>
> 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.

----- I think you are barking up the wrong tree. What good is a mirror that
will last 400 years, because that is all you'll have, if you cannot get the
signal off it. Books are readable, because we can still read unaided,
provided our language skills are sufficient.

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 technical field of electronic communication has been some of the way of
working long-term. In the analog days, signals were amplified at regular
intervals along a cable, by so-called repeaters. If the cable is submarine,
pulling such a repeater up for service is a very expensive undertaking, and
for this reason high-reliability components are used. Now, for repeaters
built in the late 1960s, where silicon transistors were readily available,
having a current amplification factor not less than 100, they still used
germanium transistors having an amplification factor of 3-5! This is because
they were proven to last. Nowadays, we have quite different technologies.

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.

If you cannot provide the machine, forget about the media.

Kind regards,

George