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From: lauren@RAND-UNIX.ARPA
Newsgroups: net.micro
Subject: CD technology
Message-ID: <55@brl-tgr.ARPA>
Date: Sun, 21-Jul-85 03:43:59 EDT
Article-I.D.: brl-tgr.55
Posted: Sun Jul 21 03:43:59 1985
Date-Received: Mon, 22-Jul-85 04:22:03 EDT
Sender: news@brl-tgr.ARPA
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The basic idea of the CD technology was for AUDIO -- the idea of CD-ROMs
came somewhat later.  The basic technology makes a variety of specific
demands on the playback systems--lenses, mirrors, distances, focal lengths,
wavelengths, etc.  You can only change these within very narrow limits
and still read the discs.  Of course, someone could go off and design
another system that works a different way... but the only thing that
keeps the costs of the players, and especially of the mastering, to
reasonable levels is the MASS volume represented by audio CD manufacturing
and playback.  Any new system is unlikely to be able to approach those
volumes.  It's pretty easy to master a CD-ROM, since you can (essentially)
use the same production line that you use for audio disks--just substitute
a 9 track tape for the usual U-MATIC cassette (SONY PCM-1610 format) 
used for audio CD input sourcing.  Still, the equipment to do this stuff
is NOT CHEAP and only becomes reasonable when you're dealing with high
volumes.

--Lauren--