ron@brl-vgr.ARPA (Ron Natalie <ron>) (04/26/84)
STOP! CD is not CED. CED is the RCA stupid video format with a stylus the C is "capacitive" I believe. RCA has discontinued manufacturing CED players (GOOD!). CD is COMPACT DISK and is a smaller version of the laser disk for AUDIO purposes. CD's are here to stay (for a while). -Ron
geller@rlgvax.UUCP (David Geller) (04/26/84)
Dave Ihnat seems to think that Compact audio disks (CD's) will
soon be no more. I would be absolutely amazed if this were to
happen. Why IBM alone could keep the techonology and the industry
that supports it alive (their recent order of 1.3 million CD players
supports my notion). Also - new players are being released all of
the time. Why, there is even going to be players made for cars in
the near future. Compact disks should be with us for some time.
"fortune telling in Virginia..."
David P. Geller
Computer Consoles, Inc.
{seismo}!rlgvax!geller Office Systems Group
11490 Commerce Park Drive
Reston, VA 22091
703-648-3483custead@sask.UUCP (Der cuss) (04/26/84)
Dave, you are confusing CD disks with CED disks. The CD disk referred to in the original article IS a laserdisk; the head does not touch the recording surface, and it is not on the way out. Your statements apply to the CED disk, which is different from the CD disk, so let's not mix the two, eh? custead ihnp4!sask!custead official beer-drinker of the 1984 olympics
archiel@hercules.UUCP (Archie Lachner) (04/26/84)
I believe that in this case "CD" stand for "compact disk," i.e., a small
(4", I think) laser disk, not "capacitve disk," the thing RCA recently
gave up on.
--
Archie Lachner
Logic Design Systems Division
Tektronix, Inc.
uucp: {ucbvax,decvax,pur-ee,cbosg,ihnss}!tektronix!teklds!archiel
CSnet: archiel@tek
ARPAnet: archiel.tek@csnet-relayignatz@ihuxx.UUCP (Dave Ihnat, Chicago, IL) (04/27/84)
Ok, folks enough! There've been a number of publications that have abbreviated the abbreviation, and referred to the CED disk as a CD--and I was thinking that way when I posted, ok? Sorry, and it's a non-issue, since it's the CED that's defunct. *Give 'em a match, and they'll burn Chicago to the ground...* -Mrs. Murphy Dave Ihnat ihuxx!ignatz
ptw@vaxine.UUCP (P. T. Withington) (04/27/84)
Ihnat, Geller, you're both right!
Ihnat is talking about the RCA video disk abortion, which was at one time
called "CD" (dunno, capacitive detection or some such), which *does* contact
the disk when it plays, which has been "obsoleted" by its own parent. Geller is
talking about Compact (audio) Disks, which are just small format laser disks
(except I think they have constant rotational velocity) and they do *not*
contact the disk when they play.
CD's are obsolete as the eight-track (i.e RCA plans to keep building them as
long as people buy them); but CD's are not (i.e. Phillips just invented them
and Sony just licensed them). I think I'm going to call my broker and buy some
CD's right now.
o.o --ptw
~tim@nmtvax.UUCP (04/27/84)
<Void>
When I posted this article I just naturally assumed that everyone knew
I was talking about CD laser disks. This is not the same as a certified
digital disk that is still just a plastic record. The term CD is being
associated with those new 5in (said 4in in error before) digital laser
disks that are just starting to appear in audio circles. They work just
like any laser disk and the head doesn't make contact. Unlike laser
movie disks and the like they are half the size though. Also, note that
gegabyte should be gigabyte. I was up too late that night and just didn't
know what I was thinking spelling it that way....
Tim Tucker
...ucbvax!unmvax!nmtvax!timmsc@qubix.UUCP (Mark Callow) (04/28/84)
From Dave Ihnat > Sorry, not to harp, but...a Laserdisk as to a CD disk as a Space Shuttle > at launch is to OS-360. ... > ... The head on a CD disk does make contact with the recording surface, > unlike the Laserdisk. You are confusing CD (Compact Disc, otherwise known as Digital Audio Disc) with CED (Capacitance Electronic Disc or something similar). RCA have indeed just cancelled the CED. CD's are alive and well and definitely do use lasers to read the disc. THe disc is 12cm in diameter as opposed to the laser video disc whcih is 12 inches in diameter. -- From the TARDIS of Mark Callow msc@qubix.UUCP, decwrl!qubix!msc@Berkeley.ARPA ...{decvax,ucbvax,ihnp4}!decwrl!qubix!msc, ...{ittvax,amd70}!qubix!msc "I'm a citizen of the Universe, and a gentleman to boot!"
msc@qubix.UUCP (Mark Callow) (04/29/84)
> The term CD is being associated with those new 5in (said 4in in error > before) digital laser disks... They're not 5 inches they're 12 CENTIMETRES. God! When is this country going to go metric? I am fed up with buying things in tenths of a pound... -- From the TARDIS of Mark Callow msc@qubix.UUCP, decwrl!qubix!msc@Berkeley.ARPA ...{decvax,ucbvax,ihnp4}!decwrl!qubix!msc, ...{ittvax,amd70}!qubix!msc "I'm a citizen of the Universe, and a gentleman to boot!"
judd@umcp-cs.UUCP (05/01/84)
this may not be as usefull as it sounds. since the idea is to mass-produce data
and files on these 1/2 gigabyte CD's the potential for an error to cause lots of
damage is high. eg 300 engineers get stress analysis w/ some vital parameter
wrong eg g=9.6m/s^2.
a CD format w/ a player that can write on the CD (reserve some space for corrections)
giving you a 1/2 giga PROM would be a better technology.
--
Spoken: Judd Rogers
Arpa: judd.umcp-cs@CSNet-relay
Uucp:...{allegra,seismo}!umcp-cs!juddrehmi@umcp-cs.UUCP (05/01/84)
From: judd@umcp-cs.UUCP (Judd Rogers) this may not be as usefull as it sounds. since the idea is to mass-produce data and files on these 1/2 gigabyte CD's the potential for an error to cause lots of damage is high. eg 300 engineers get stress analysis w/ some vital parameter wrong eg g=9.6m/s^2. /* ------------- */ I kind of doubt that they'd stamp out these things and sell them without verifying them first. There would also doubtless be error correction of some form. In fact, even on the audio discs they have some elaborate error detection/recovery cruft. Any other media that programs get distributed on is susceptible to errors. How many times have you received a bogus distribution tape, for example? Not to mention that it would seem harder to corrupt data burned solidly into a piece of plastic (or whatever it is) than it would to corrupt data floating as magnetic domains on a film of mylar. And don't forget that there is another eighth-inch layer of plastic over the coded piece of plastic. Pretty tuff. Then again, there are still those who want to go back to the "reliability" of stepper relays. *Sigh*... -rehmi -- Uucp: ..!seismo!umcp-cs!rehmi By the fork, spoon, and exec CsNet: rehmi.umcp-cs@csnet-relay of Khron, Kernel ContreMain, ArpaNet: rehmi@maryland Earl of Tetravale & Tumbolia.
ignatz@ihuxx.UUCP (Dave Ihnat, Chicago, IL) (05/02/84)
Sorry, not to harp, but...a Laserdisk as to a CD disk as a Space Shuttle at launch is to OS-360. Both are big, and impressive--each in its way--but one is, if not the pinnacle of achievement in its field, a milestone on the way; while the other is just a big, ugly abortion. I submit that CD is the latter. The head on a CD disk does make contact with the recording surface, unlike the Laserdisk. Both the media and the read head suffer from this. I've heard a rumor that the CD is to soon be no more, while the future of the Laserdisk seems assured, so let's not mix the two, eh? In a nitpicking mood, Dave Ihnat ihuxx!ignatz
judd@umcp-cs.UUCP (05/03/84)
Someone missunderstood me. The problem I see with so much data going out is
Organization: Univ. of Maryland, Computer Science Dept.
Lines: 20
that it is very easy to make a small mistake (my example was g=9.6 vs 9.8m/s)
that does NOT show up in testing the software and data bases. I was not talking
about errors in reading from the CD. Those are taken care of by the hardware.
We all know that bugs in software need to be fixed all the time. Even w/
software that has been around for years and years. With so much stuff on these
disks there will be corespondingly more fixes that need to be done. This will
drive up the distribution costs as every release will require junking all the
old disk. If there is know way to make minor changes the CD may be useless for
distributing software.
There is an even worse problem related to the above. Since these things are
going to be mass produced only established software that a reasonably large
number of people want will be put on them. Since the available software is
by no means optimal (some would say worthless) for the tasks they perform
I see no future for the CD.
--
Spoken: Judd Rogers
Arpa: judd.umcp-cs@CSNet-relay
Uucp:...{allegra,seismo}!umcp-cs!judddya@unc-c.UUCP (05/04/84)
References: umcp-cs.6839
I think the bit error rate ( uncorrected ) for a clean Audio Compact Disc
is something like 10 e-04. Corrected, it is much higher. However, when they
get dirty, things rapidly deteriorate ( I heard a filthy one on a local station,
they, too skip just like regular records if fouled up enough ).;
For people interested in the technical aspects of this, there is an
excellent treatise on the Compact Disc and its error correction schemes in
either April or May "Audio".
The Audio Compact Disk has got to be at least 10,000,000 times better
than Shugart SA712 1/2 height floppies (thus far, I am 0 for 8 on these.
Now Vertex, on the other hand, I am 7 for 7.) { NOTE REPLACE FLOPPIES WITH
WINCHESTER ABOVE--ooops!) Anyone have any horror stories about SA712's
dyamsc@qubix.UUCP (Mark Callow) (05/04/84)
this may not be as usefull as it sounds. since the idea is to
mass-produce data and files on these 1/2 gigabyte CD's the
potential for an error to cause lots of damage is high.
The potential for error ought to be very low. CD encoded music contains
ample amounts of error detection and correction information. The chances
of errors going by undetected are at least as small as on magnetic discs.
--
From the TARDIS of Mark Callow
msc@qubix.UUCP, decwrl!qubix!msc@Berkeley.ARPA
...{decvax,ucbvax,ihnp4}!decwrl!qubix!msc, ...{ittvax,amd70}!qubix!msc
"I'm a citizen of the Universe, and a gentleman to boot!"