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Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!tgr!munck@MITRE-BEDFORD.ARPA
From: munck@MITRE-BEDFORD.ARPA
Newsgroups: net.micro
Subject: Re: CD-ROMS -- access times
Message-ID: <42@brl-tgr.ARPA>
Date: Sat, 20-Jul-85 23:47:38 EDT
Article-I.D.: brl-tgr.42
Posted: Sat Jul 20 23:47:38 1985
Date-Received: Mon, 22-Jul-85 03:58:26 EDT
Sender: news@brl-tgr.ARPA
Lines: 18


  I don't understand exactly what the problem is; maybe a bad choice
of technology?  I saw a demonstration in 1976 of a great graphics display
built by Charles Lang at Cambridge U.  It used voice-coils and mirrors to
point a laser with tremendous accuracy and speed at a 5 cm square target,
writing with a resolution of 4000 line pairs. It was aimed by splitting
off a bit of the laser beam and counting interference fringes, giving 
essentially digital aiming with (I think) 24 bits of resolution.  I saw it
draw a street map of London in about 30 seconds, and then redraw it with no
visible thickening of the lines.  (The little square was being projected
on a 1m square screen.)

  So why not build a CD-ROM player that works that way?  Assuming that 
it's also capable of audio, you could use the high-res D-A converters
to drive the voice coils. (Or single voice coil, assuming a spinning
disk.)  Sounds pretty cheap to build, and more than fast enough.
            -- Bob Munck, MITRE Corp.
               (..linus!munck.UUCP)