rouellet@clitus.cs.uiuc.edu (Roland Ouellette) (04/09/90)
After the words peer review came into my mind, I reposted the previous
article in our internal VAXNotes CD conference. There's been a rather
heated discussion of Armor All going on for a while there, and adding
a little fuel to the fire never really hurts. This response raises a
couple of interesting points. I really wonder why the lens of the
player couldn't be coated instead of the disc. The blue lasar
comments refer to the discovery of a solid state lasar which emits
blue light. Using a shorter wavelength should allow porportionately
higher bit density. Predictions of 3 to 4 hour CDs have been made.
My guess is that to be backwards compatible, they'd need to contain
two lasars (the way that 78s need a different stylis).
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Note 421.92 Armor All Protectant 92 of 93
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re: .90
Well, if that's a simple spoof of some kind, someone sure went to a
whole lot of trouble to sound at least half plausible to a non-chemist
like me.
On the other hand, I suppose it could be a hoax intended to provide
financial gain for the authors.
But for just a moment, let's make the (perhaps dangerous or foolish)
assumption that it's on the level. What then? Well I have two
comments, for whatever they may be worth.
1) Could not the same thing be accomplished much more practically by
building players with optical near-infrared band-pass filters on the
laser and/or photoreceptor? If not, why not? This is just a quick
guess on my part.
2) We've been hearing a lot about the recent supposed development of a
bright blue laser that would make it possible to manufacture 5" CDs
that contain 3-4 hours worth of music. Some have predicted that such
players will completely replace the red laser players in 2 to 5 years.
I, for one, have been assuming that these blue laser players would have
the ability (either automatic or by manual selection) to also play the
current day CDs designed for red lasers. (Sort of like 33 rpm
turntables for a long time were made with a 78 speed setting.) If one
coats one's current day CDs with a substance that only passes light in
the near-infrared, it would seem that one is making it unlikely that
future blue laser players will be able to play these discs. I would
think long and hard before putting this stuff on my collection, which
could be relegating it to the scrap heap in less than 10 years. I
certainly expect my collection to have a useful life of much more than
that. For this reason alone, even if there were no other harmful side
effects, I would hesitate to put this stuff on my discs, or buy discs
from any manufacturer who uses it by default.
Just some off-the-cuff thoughts. Anyone with an interest in posting
this note back to the usenet discussion, please feel free. I don't
care, and I wouldn't know how to do it anyway.
B
--
= Roland G. Ouellette ouellette@tarkin.enet.dec.com =
= rgog1070@uxa.cso.uiuc.edu rouellet@babym.cs.uiuc.edu =
= "You rescued me; I didn't want to be saved." =