Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!amdahl!oliveb!cygnet!mark
From: mark@cygnet.CYGNETSYSTEMS (Mark Quattrocchi)
Newsgroups: comp.ivideodisc
Subject: Re: CD-ROM
Message-ID: <687@cygnet.CYGNETSYSTEMS>
Date: 14 Jan 88 21:31:30 GMT
References: <19898@teknowledge-vaxc.ARPA> <4469@watdragon.waterloo.edu> <2132@bloom-beacon.MIT.EDU> <4481@watdragon.waterloo.edu>
Reply-To: mark@cygnet.UUCP (Mark Quattrocchi)
Organization: Cygnet Systems -- Sunnyvale, CA
Lines: 30

In article <4481@watdragon.waterloo.edu> daford@watdragon.waterloo.edu (Daniel Ford) writes:
>
>In article <2132@bloom-beacon.MIT.EDU> yba@athena.mit.edu (Mark H Levine) writes:
>>In article <4469@watdragon.waterloo.edu> daford@watdragon.waterloo.edu (Daniel Ford) writes:
>>>As I understand it, CD ROM discs in their current form could not be
>>>double sided.
>>This seems unnecessarily pessimistic on several counts:
>>
>>Music CDs which use the same basic technology + a D/A converter come double
>>sided, CD-ROM drives can mechanically accomodate these disks as far as I have
>>seen (they use the same bloody drive in the case of Hitachi product I was
>>shown, and the only restriction on WORM product was the form factors involved).
>>The labelling problem is somewaht silly -- two-sided music cds have labels on
>>both sides, as do 8, 10, and 12 inch optical disks for video (with 2 sides).
>>The lasers do not seem to have any trouble with the plastic coat, nor would
>>I expect any.
>
>
>
>
>I may be displaying my ignorance, but as far as I know music CD's do NOT
>come double sided.  They may look double sided because one can see the
>silver through the transparent top side, but they are not.  Also, I don't see
>how one could expect a laser to penetrate an optically opaque label and read
>the data stored on the disk surface below.  This seems doubly strange since
>the manual for the above mentioned Hitachi drive warns that if the 
>disk surface is fogged by condenstation the drive is likely to have problems 
>reading data.


Absolutely correct! Givem hell Harry.