From: CLASSICCMP_at_trailing-edge.com <(CLASSICCMP_at_trailing-edge.com)>
Date: Thu Jul 29 11:15:27 1999

>Thats something that has been puzzling me in this discussion, whats this
>about CDROM being better archival than CDR? Kodak is saying 100 years for
>their CDR I think.

Lifetime estimates are all, in reality, just estimates. Most of them
have some good scientific reasoning behind them, and usually take
"accelerated aging" tests (high temperature/humidity/light situations)
and extrapolate these results to more normal storage conditions.

Indeed, the lifetimes of CD-R's are estimated to be at least in decades
if not longer, but these are all estimates. Real pressed CD-ROM's have
been around for about two decades now, and except for a few manufacturing
snafus early on, they are known to be good for at least that long.

In addition, CD-R's occasionally have interchangability problems -
a brand X disk burned on a brand Y recorder might very well be unreadable
on a brand Z player. Interchangability isn't a big problem for fairly
recent CD-ROM readers, but for, say, someone hooking up an ancient RRD40
player it may very well be an issue. Pressed CD-ROM's tend not to have such
interchangability problems (though certainly I think we've all run across
cases where brand Z player won't read one disk, while brand Y will.)

I tend to agree that CD-R's are probably good enough, but better is always
the enemy of good enough, and real CD-ROM's would be better if there's
enough volume to justify them.

 Tim Shoppa                        Email: shoppa_at_trailing-edge.com
 Trailing Edge Technology          WWW:   http://www.trailing-edge.com/
 7328 Bradley Blvd		   Voice: 301-767-5917
 Bethesda, MD, USA 20817           Fax:   301-767-5927
Received on Thu Jul 29 1999 - 11:15:27 BST

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