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From: drg@briar.UUCP (Don Gentner)
Newsgroups: net.periphs
Subject: Re: Compact-disk player, cheap CD-ROM reader??
Message-ID: <476@briar.UUCP>
Date: Thu, 30-Oct-86 08:16:22 EST
Article-I.D.: briar.476
Posted: Thu Oct 30 08:16:22 1986
Date-Received: Tue, 4-Nov-86 01:08:44 EST
References: <41@nikhefk.UUCP>
Organization: Philips Laboratories, Briarcliff Manor, NY
Lines: 30
Keywords: CD-ROM, Compact-disk player
Summary: CD-ROM is more that CD-Audio



In article <41@nikhefk.UUCP>, henkp@nikhefk.uucp (Henk Peek) writes:
> -Is the CD-ROM error-correction and data-format identical
>  to the (audio) compact-disk.
> -Are there procedings of the first CD-ROM conference 1986?
> -Are there other usefull references?

The CD-ROM format is built on top of the CD-Audio format.  The basic
data unit in CD-Audio is the frame (24 bytes of audio data).
In CD-ROM, the basic unit is the block, made up of 98 frames for a
total of 2352 bytes of data per block.  There are two CD-ROM formats.
In Mode 1, a block contains 16 bytes of header, 2048 bytes of user data,
and 288 bytes of error detection and correction codes.
These 288 bytes of ED/EC are in addition to the normal error detection
and correction codes in CD-Audio, giving Mode 1 CD-ROM a nominal error
rate of 1 error per 200 million discs!!!
In Mode 2, a block contain 16 bytes of header and 2336 bytes of
user 18  data.  Mode 1 is normally used for text and data; Mode 2
is used for graphics and sound, where a few errors don't hurt so much.

I don't believe there are procedings of the CD-ROM conference.

There's some discussion of CD-ROM format in Byte, May 1986, pp 164-165.

				Don Gentner
				Philips Laboratories
				Briarcliff Manor, NY 10510
				gentner@nprdc.arpa
				{seismo,decvax,ihnp4}!philabs!gentner