Path: utzoo!mnetor!uunet!husc6!bloom-beacon!athena.mit.edu!yba
From: yba@athena.mit.edu (Mark H Levine)
Newsgroups: comp.ivideodisc
Subject: Re: CD-ROM
Message-ID: <2132@bloom-beacon.MIT.EDU>
Date: 4 Jan 88 06:32:56 GMT
References: <19898@teknowledge-vaxc.ARPA> <4469@watdragon.waterloo.edu>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: yba@athena.mit.edu (Mark H Levine)
Organization: Massachusetts Institute of Technology
Lines: 36

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.
>
>Another simple problem with two sided discs is labeling.  Where would
>you put the name of the disc?  LP's get around this problem by being large,
>not really a solution here....
>
>I believe that it may be possible to construct a drive that would read
>both CD ROM and WORM discs but there are some problems.  The big one is
>the different recording formats used in the two types of disks.  
>

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 expect you will see read/write media just about the time compatible WORM
drives would be ready, so the entire problem there may be moot.

This is of course only my opinion, which I do not represent as authoratative.

I work on integration of video with our X Window System here at MIT, along
with the Video Courseware Group which is developing interactive teaching
material.  We have video workstations which can put video inside a window,
have attached CATV and 12 inch video disk players, and are producing our
own disks.  So far we have only experimented briefly with the CD format, and
are looking to CDI and DVI as areas to explore in the future.  I would be
interested in hearing experience others may already have had with these.