Path: utzoo!mnetor!uunet!husc6!bbn!rochester!udel!gatech!ufcsv!codas!burl!clyde!watmath!watdragon!daford
From: daford@watdragon.waterloo.edu (Daniel Ford)
Newsgroups: comp.ivideodisc
Subject: Re: CD-ROM
Message-ID: <4515@watdragon.waterloo.edu>
Date: 7 Jan 88 20:16:52 GMT
References: <19898@teknowledge-vaxc.ARPA> <4469@watdragon.waterloo.edu> <2132@bloom-beacon.MIT.EDU> <4481@watdragon.waterloo.edu> <7990@e.ms.uky.edu>
Reply-To: daford@watdragon.waterloo.edu (Daniel Ford)
Organization: U. of Waterloo, Ontario
Lines: 40

In article <7990@e.ms.uky.edu> david@ms.uky.edu (David Herron -- Resident E-mail Hack) writes:
>Music CD's do indeed use the same formats as Data CD's.
>
>Music CD's are single sided whereas Data CD's can be double sided.
>
>what I see properly.  On a Music CD there's a band of "smooth-continuous"
>looking "silver" around the outside, inside that there's a band of not
>so "smooth-continuous" looking "silver", inside that there's another band
>of "smoth" stuff.  I assume that the data is in the not-so-smooth parts
>and the smooth parts don't hold any data and can be used for labelling.

The inner band of "smooth-continuous" silver has no data and is called
the "lead in".  The outer "smooth-continous" area also has no data and is called
the "lead out".  No labeling should go on these areas.

The lead in starts from the centre to allow for playing different sized disks
on the same drive.  I believe that there is now a CD single that is a bit
smaller than the regular disc and holds about 15 to 20 minuties of music.

>I had a thought.  Do WORM drives use the same data formats?  If not, can they?
>I had this silly thought about making backup copies of my Music CD's :-).

The two types of discs use different recording formats.  WORM drives use
a CAV scheme just like magnetic disks and CD ROM uses CLV which is basically
one long spiral track.  You could make a "backup" but the discs are so
tough I wouldn't worry about it.

In Japan they are marketing a hybrid disk that uses CD for sound and
optical disk for video.  These little babies are used to sell music video
singles.  Apparently it is a hot item.


					Dan Ford


-- 
---------------------------------------------------------------------
Daniel A. Ford 					daford@watdragon.uucp
CS Department                         daford%watdragon@waterloo.csnet
U. of Waterloo       daford%watdragon%waterloo.csnet@csnet-relay.arpa