X-Message-Number: 5550
Date: Mon, 8 Jan 1996 09:22:40 -0800 (PST)
From: Joseph Strout <>
Subject: Re: Data storage

In message #5547, John de Rivaz wrote:

> Unfortunately it is highly likely that CDROMS will not hold their data for 
> ever or even for decades. I am not sure what to suggest as a storage medium 
> for data to be retained for hundreds of years, but I think that some films 
> are being converted to video and that is being recorded in monochrome as a 
> waveform onto optical film. The argument is that colours fade in colour 
> prints, but a monochrome waveform that can be electronically reconstituted 
> into a picture would maintain the colours properly.

Monochrome film fades too, probably much faster than CD-ROMs degrade, 
since the information is encoded chemically rather than physically (i.e. 
by the presence or absence of matter).  We tend to think of B&W photos as 
lasting a long time, but we're not using them to store digital 
information; the picture degrades a lot, but we can still recognize it.

Fortunately, most of the data I was thinking of archiving has this same 
property; if we don't use any compression, then loss of a few bits here 
and there will not destroy the text or images, but merely degrade them.  
We could probably come up with some clever checksum schemes which would 
allow automatic error correction in most cases, but even without this, I 
think the message would be clear.  Tekt is quife readaple even wit# 
axhigh pe,centage of miptakes, and pictures or sound even more so.

Of course, copying to new media as it matures (as you suggest) is a great 
idea.  But even if the company collapses and the CD-ROMs gather dust for 
a few centuries, I bet there would be enough left of the pits to decipher 
the info even with current (laboratory) technology.  With modest 
nanotech, it should be even easier.

OTOH, if the cryonics company collapses, it becomes a moot point...

Many thanks  for your comments.

|    Joseph J. Strout           Department of Neuroscience, UCSD   |
|               http://www-acs.ucsd.edu/~jstrout/  |

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