# Talk:Compact disc

(Redirected from Talk:Compact Disc)

## Size of the data-holes

I am interested in the size of the data-holes (the binary is stored in various small holes) and cannot find any info on the topic. Any of you know the radius of the holes? --Shivaya4 (talk) 09:16, 8 February 2010 (UTC)

The term I searched for was q=compact+disc+pit+radius; from which the seventh and eighth results gave values of:
Source Pit depth Width Length
[1] 100 nm 500 nm 850–3,500 nm

The first of those gives reasonable explanations for two of the values (subdivision of the wavelength of the light used) and lengths being 3–11 times bit rate (at 1.2–1.4 m/s), but perhaps you can investigate further (eg. the Patents) and come back with what you've found. The first also points out the length varies depending on the linear velocity across the CD.

I note that this is your first contribution to Wikipedia (welcome), so I really hope I didn't just do your homework for you. —Sladen (talk) 09:51, 8 February 2010 (UTC)

## Compact Disc release dates

I am confused by the various dates given for the release dates of the CD onto the general market, Some dates show 1980 some 1982, however, I have handled and listened to a CD in 1977/8. Also, Philips claims to have invented the CD in order to replace their Cassette Tape invention, but a Mr Russell claims to have invented the CD around 1965. What's correct? Barry. —Preceding unsigned comment added by 203.129.146.52 (talk) 07:12, 26 February 2010 (UTC)

Barry, you are absolutely right. I brought this error in the wiki page up a number of years ago, but it was decided by...someone who wasn't alive in 1970 and held a CD in their hands...to maintain that the compact disc was invented in the 80's by Philips. James Russell did, in fact, invent the compact disc in 1965. This is a perfect case in point why Wikipedia cannot be used as a reference in legitimate historical discourse.
Phearox (talk) 17:37, 4 July 2011 (UTC)
Guys, this has been discussed multiple times. There are links to the archives closer to the top of this page. Click on them and use your browser to search for "russell".
Wikipedia would be a worse resource if it relied on "I was there" or "I am an expert" kinds of unsubstantiated claims, no matter how true or plausible they may be. If Russell invented the CD as we know it, surely there will be some historical, citable published somewhere about it. If there is a noteworthy debate on the subject, surely the debate itself has been covered in a newspaper, journal, conference paper, or thesis. Otherwise it's just folklore. Familiarize yourself with the Wikipedia policies WP:V and WP:RS and come back with things we can cite. —mjb (talk) 18:39, 4 July 2011 (UTC)
Well, There are patents in his name on the subject (yes, the original purpose was video and audio together, but the technology is unarguably covered by the patents): http://www.google.com/patents?vid=3501586, http://www.google.com/patents?vid=3795902 (Ironically, I found these right on his Wikipedia entry...) There are meeting minutes from live discussions with the man himself: http://www.aes.org/sections/pnw/pnwrecaps/2005/russell/. You could also tell the Massachusetts Institute of Technology they are wrong if you like: http://web.mit.edu/invent/iow/russell.html.
I don't mean to sound combative, but this is something that has frustrated me for years - the presence of such an overabundance of evidence (patents, live presentations and meetings, even research by respected educational institutions), and yet there is not even the slightest mention of Russell in the compact disc entry of Wikipedia. An absolutely essential piece of the compact disc's history has been omitted from a resource some children in school often take as gospel.
I wouldn't defend this point so vehemently except that I /held a CD in my hands/ prior to the supposed invention by Philips. The stance that Sony/Philips invented the CD is preposterous on its face. Phearox (talk) 19:34, 4 July 2011 (UTC)
Naturally, there is always prior art that contributes to aspects of a given technology. When writing the history of pretty much anything, one must make editorial decisions on where to start telling the story. How far back do you reach? How much of the technology that predated and/or was built upon to create what we know today as the Compact Disc needs to be mentioned in the article on the Compact Disc? There's already an optical disc article linked to from the lead, and a videodisc one as well. Those have their own histories which overlap some with the CD history. I mean, I don't doubt that you held in your hands an early optical disc that maybe contained audio and/or video data in some pre-Red Book format. Was it all-digital? Was it referred to as a Compact Disc, the name Philips came up with in 1977–1979, as reported by the BBC? I'm guessing no and no. So if you held something more aptly described as CD-like, is it not an overstatement to say Sony & Philips are wrongfully claiming to have created the CD? Compact Disc is a specific name for a specific combination of technologies and standards. It's not a generic name for all small audio optical discs ever invented or demonstrated. So lines have to be drawn.
I hope I don't sound intractable; there's always room for improvement in any article, and this one is no exception. Others may disagree, but I personally don't think it would hurt the article to make some mention of Russell's work, using whatever good sources we can find. But we do have to avoid characterizing it in the way some seem to be advocating, which is along the lines of "Sony and Philips have perpetrated a great fraud, lo and behold the CD was actually invented by someone else, as shown by these patents." You'll have more success if you try not to focus on debunking; the article has to focus on how the CD as we now know it came into existence, without reaching too far into the history of all optical discs or placing undue importance on dead-end branches of digital audio disc research. —mjb (talk) 23:12, 4 July 2011 (UTC)
I would suggest that the information you present about James Russell could help improve Optical_disc#History. Be careful about using primary sources they're useful in some technical contexts but using them to try and demonstrate who was first would probably constitute original research. --Kvng (talk) 19:53, 6 July 2011 (UTC)
The year 1980 is usually referenced as the published date of the RED book, which later became the first standard for CD Audio format (IEC 908). Could you kindly point out where in the main page 1980 is referred as the first year compact disks were released? —冷雾 (talk) 06:24, 3 May 2016 (UTC)

## Disc Manufacture Clarification Request

After reading this article, I am left unclear on the manufacturing process. In the Manufacturing section, does the initial disc formation from plastic granules introduce a spiral into the resulting surface? Later, does the data die press the data into the metalic layer alone? Is the thin, metal coating thick enough to hold the data or is the plastic substrate involved? Without clarity on these areas, I am left unable to think clearly about the physics of what happens when a disc degrades. Of course, commercially recorded discs, writable discs, re-writable discs, etc. are all different. My hope is that this article will be updated with greater detail in the Manufacturing section. Ideally, a disc diagram clearly showing the location(s) of the spiral and data will be provided. I suspect that the data reside in two places: in the metalic layer and in the plastic substrate upon which the metalic layer has been coated. However, it isn't clear to me how data could be introduced into the plactic substrate without the use of heat. Heat is not mentioned in the data impression step. --JimOfCR (talk) 15:37, 13 April 2010 (UTC)

It would be great to have this information added to the article (eg. with a diagram showing the construction at each stage of manufacture). Could you possible assist in researching it (eg. the best place to start is probably the original Philips patents). —Sladen (talk) 17:05, 13 April 2010 (UTC)
I too found the manufacture section lacking, specifically with "After a metallic reflecting layer […] is applied to the clear blank substrate…" but no mention of how this seemingly magical process is accomplished. I will continue my search as to how a metal so finicky as Aluminum can be deposited over 100-500µm "pits" and "lands" of polycarbonate plastic without destroying it. Hopefully someone more knowledgeable will be able to expound the article to include a more detailed explanation of this extremely interesting part of the process. —98.210.138.200 (talk) 05:02, 21 December 2010 (UTC)

## the longest cd

The longest known single compact-disc is The Rest of New Order by New Order, which lasts exactly 80 minutes (80:02 with pregap), which is the longest a single CD album can go. Maybe this should be mentioned in the article. —Preceding unsigned comment added by 213.83.125.225 (talk) 09:00, 24 June 2010 (UTC)

The same sentence above was inserted[2] verbatium today on the Album article, also without citation. —Sladen (talk) 09:11, 24 June 2010 (UTC)

## Physical parameters

This says that the speed is different from the edge to the middle. OK. But it also says the RPM is different from edge to middle! That's literally impossible! What the heck is going on here? --Jtle515 (talk) 17:22, 14 July 2010 (UTC)

Speed and rpm are the same thing—rpm is spinning speed—and the spinning speed lowers as the CD plays. It starts revolving fast at 495 rpm at where the laser is reading a short inner track near the middle, then gradually and smoothly reduces in rpm (spinning speed) until the laser is near the outside edge and the rpm is about 212, for a maximum length CD that has data all the way out to the outside edge. The laser reading speed is constant, called a constant linear velocity (CLV)—it reads about 1.2 meters (47 inches) worth of pits and lands every second for a 1x speed realtime player. To me, the article is quite clear and I don't see the need to modify it. Binksternet (talk) 18:27, 14 July 2010 (UTC)

Speed and RPM are two different things- Speed is linear, and because of the increased radius near the edge, would be higher than closer to the center on a CD. RPM is the same no matter what- the 'top' point of a disc on the outside and on the inner part will always reach the 'top' at the same time. Think of it this way, if you spin the disc 360 degrees in one minute, you are spinning every point on that disc 360 degrees in one minute. RPM is the same, in this case 1 RPM, while speed is different, as the point on the outside has to cover more distance than the inner point in the same amount of time. 66.143.200.27 (talk) 05:30, 11 December 2010 (UTC)

I noticed that reference 36 (website) is now down. — Preceding unsigned comment added by 69.204.43.162 (talk) 03:24, 31 May 2015 (UTC)

Hi, 69.204.43.162 (Your name please?) Reference number changes all the time. Did you mark it as Dead Link? —冷雾 (talk) 06:32, 3 May 2016 (UTC)

## History Compact Disc, further reading

Hans B.Peek, "The Emergence of the Compact Disc", IEEE Communications Magazine, Jan. 2010, pp.10-17. —Preceding unsigned comment added by Peek (talkcontribs) 11:04, 25 July 2010 (UTC)

Dear Mr Peek, does any of your papers contain the precise physical parameters of the compact disks? See this section. —冷雾 (talk) 06:38, 3 May 2016 (UTC)

## CD Playing time

A careful read on this article http://www.exp-math.uni-essen.de/~immink/pdf/beethoven.htm will reveal that the cd playing time of 74 minutes is more of a competition thing between Sony and Phillips than the usual story about Beethoven'w 9th. I would suggest reading the article and maybe correct the wikipedia article. —Preceding unsigned comment added by 88.218.48.34 (talk) 19:18, 27 November 2010 (UTC)

## 2-hour mono CDs announced in 1986

A Feb. 22, 1986 article in Billboard repeated a claim from Qualiton Imports that the BIS Records label was going to release CDs which, due to their mono content, had 2-hour playing time per disc, breaking the (then-) 75-minute barrier. The actual CDs that got released were nothing special: Gould Plays the Piano in Stockholm, 1958 2-CD set and Nicolai Gedda: Verdi 2-CD set, naturally both just containing mono content mastered in 2 channels. Apparently the Billboard article was a gross misinterpretation of the actual release announcement, whatever it was. Red Book doesn't allow for a 1-channel audio stream, does it? And the subcode can't theoretically address more than 99 minutes, anyway, right? Or was such a thing actually possible? —mjb (talk) 07:45, 28 January 2011 (UTC)

I recall that the disappointment of twin mono CDs was that the hardware vendors did not offer a CD player to address the format. No CD player I ever saw was able to play one channel and direct its sound to both Left and Right output jacks, then start over at the other channel and do the same thing. Binksternet (talk) 13:36, 28 January 2011 (UTC)
One of the major errors of the Red Book spec is that it assumes all recordings will be two-channel. (Hey, who wants to listen to mono?) Oddly, a quadraphonic format was spec'd, but it wasn't playable on two-channel machines. Duh. WilliamSommerwerck (talk) 14:03, 16 February 2011 (UTC)
My very belated informational two cents: While browsing in the big San Francisco Tower Records store sometime around 1988, I was pleasantly surprised to see a CD set of a vintage mono recording of, IIRC, Wagner's Ring cycle (which normally requires around ten CDs) packaged with a simple little passive mixer unit -- pairs of RCA jacks in and out and a L-stereo-R selector on the input side -- that allowed the number of discs to be halved. About time, I thought, as most of my listening in all genres is to pre-stereo-era recordings. The gizmo appeared to add not more than twenty dollars to the cost of the set, more than offset by the halved disc cost. The same thing can be done less neatly and conveniently with a "Y" splitter cable, by plugging the single end into the CD player's left or right output jack as needed. The problem then becomes one of indexing the tracks for normal access. Rashly assuming that, as with floppies and hard disks, a CD's index table can point to start bytes anywhere on the disk, allowing overlapping areas to be specified, the user would still be obliged to remember to switch from one channel to the other to select from the corresponding group of tracks; otherwise, they would hear the alternate-channel material, almost certainly "joined already in progress" at some awkward and jarring point. 66.81.220.42 (talk) 13:01, 23 August 2016 (UTC)

## CDR Capacity and Speed

Firstly, would there be any value in updating the stated maximum write speed of CDRs to 52x as these are now widely available? Secondly, how about mentioning CDRs with a capacity of 90mins/800MB and 100mins/900MB? They're available at various online stores in the UK and I imagine elsewhere, too. (One site picked at random: www.digitalpromo.co.uk) SP1R1TM4N (talk) 18:15, 10 February 2011 (UTC)

## History

The History section is badly over-written. It can be cleaned up without removing useful content. I'll take a crack at it later today, or tomorrow, unless someone objects. WilliamSommerwerck (talk) 14:06, 16 February 2011 (UTC)

## Blu-spec merge

Edokter (talk · contribs) has suggested a merge of Blu-spec CD into this article. We might want to also consider a few other similar techniques as part of this proposal.

I oppose this proposal. I could not find a good place to work in this material. It looks like Compact Disc manufacturing might be a more workable merge destination but I am reluctant to clutter that article with these marketed refinements to the basic process. --Kvng (talk) 13:36, 8 May 2011 (UTC)
I support this proposal As the Two formats are compatible and the Blue-spec CD is playable on any CD player, I think it would make for a noteworthy section in the Compact Disk article. z'Comandif l'Statentaru l'Zeklingtonum! (talk) 22:24, 9 November 2011 (UTC)
I support this proposal Unless someone is planning a large increase in the size of the Blu-spec CD article, it makes an ideal subheading in this page, and unified information about, as pointed out above, a backward compatible formatTim bates (talk) 11:02, 16 December 2012 (UTC)

## 30th birthday coming 17 August 2012

It would be good to have the article improved to meet WP:Featured article standards in the next few months so that it can be featured on the main page on the 30th birthday of the CD: 17 August 2012. Binksternet (talk) 02:51, 11 December 2011 (UTC)

## James Russell the CD inventor

This must in History: "The Compact Disc, or CD, is an optical disc used to store digital data, originally developed for storing digital audio. In 1965, James Russell acted upon his idea that the music industry needed a new medium whereby a gramophone record and the needle on a phonograph would no longer come into contact with one another. With an interest in lasers, Russell soon began his research in an optical system that would replace a phonograph's needle and replace it with a laser that would read codes in order to record and playback sound.[173][174] At 12 inches (30 cm) in diameter, Russell in 1970 had successfully invented and built the world's first compact disc that contained digitized codes etched onto the disc that could be read from a laser.[175][176][177][178] After partnering with Digital Recording which was later acquired by Optical Recording Corporation, Russell and the parent company that he worked for, found it increasingly difficult to enforce and protect his patents from infringement by competitors such as Sony, Philips, and Time Warner who all profited from Russell's invention. The belief that Dutch and Japanese scientists "invented" the compact disc is a misconception in the sense that Philips and Sony used Russell's underlying technology in order to develop a disc more refined, practical, smaller and sophisticated. In 1982, Sony and Philips had commercially introduced the compact disc, twelve years after Russell had already created a working prototype in 1970. By 1986, Optical Recording decided to legally act by suing Sony, Phillips, and Time Warner. Two years later, the company came to a licensing settlement with Sony and soon thereafter, agreements with Phillips and others soon followed, including a June 1992 court ruling that required Time Warner to pay Optical Recording \$30 million due to patent infringement." — Preceding unsigned comment added by 87.160.120.223 (talk) 15:49, 22 January 2012 (UTC)

http://inventors.about.com/od/qrstartinventors/a/CD.htm http://web.mit.edu/invent/iow/russell.html — Preceding unsigned comment added by 87.160.98.84 (talk) 16:22, 22 January 2012 (UTC)
http://www.google.de/imgres?imgurl=http://www.babusinesslife.com/Media/images/EntrepH0509-James-T-Russell-ea00887c-56f2-4649-8471-2063986ff745.jpg&imgrefurl=http://www.babusinesslife.com/Tools/Entrepreneurship/The-Digital-Music-Revolution.html&usg=__J9XXQwXyu19tJTkOCkMgmBw5AUw=&h=412&w=605&sz=49&hl=de&start=0&zoom=1&tbnid=1bYdt99WYhV0QM:&tbnh=127&tbnw=186&ei=TkEcT_eUBImCtQaTzLVH&prev=/search%3Fq%3DJames%2BT%2BRussell%26hl%3Dde%26biw%3D1170%26bih%3D639%26gbv%3D2%26tbm%3Disch&itbs=1&iact=hc&vpx=95&vpy=153&dur=177&hovh=185&hovw=272&tx=131&ty=202&sig=113535680373983037897&page=1&ndsp=21&ved=1t:429,r:0,s:0 — Preceding unsigned comment added by 87.160.96.158 (talk) 17:05, 22 January 2012 (UTC)

I think the history section of the article would be better if some reference were made to James Russell, as the above-user mentions. From everything I've read, Russell played a key role in the invention of the compact disc. Starting with Philips and Sony is, in effect, beginning in the middle, instead of at the start. (I hope this post meets the applicable criteria - it is my first post. John M. Becker173.166.126.249 (talk) 17:26, 8 January 2014 (UTC)

## 700MB equals 737,280,000 bytes?

This article is a key reference work for humanity. It is too vague and ambiguous to say the standard data capacity of a CD-R is "700MB", even with the explicit binary qualifier. We need and deserve an exact number of stated data bytes of capacity, with whatever qualfiers are needed, about being nominal and varying with the phase of the moon... WHAT IS THE ACTUAL NUMBER OF BYTES OF DATA CAPACITY ON A STANDARD 700MB CD? The CD-R article says 737,280,000 bytes -- maybe that number should be in this main article? -96.233.20.116 (talk) 22:45, 3 June 2012 (UTC)

Any precise figure is somewhat irrelevant as there's a tolerance range on many of the parameters for one thing (track spacing, pit and land sizes), and there's a difference between red book CD audio (with two layers of error correction) and CD-R data discs with a third layer reducing capacity to improve error-recovery. A further problem is that the data storage and data communications and telecoms industries tend to refer to bit rate (sometimes symbol rate) or capacity with decimal prefixes (kilo=1000) while the software industry tends to use binary prefixes (kibi=1024) or out of tradition treat use the symbol of the decimal prefix with the value of the binary one. CD users will often have binary capacities reported as if decimal by their computer, but the media will often use the decimal prefix on its packaging and may refer for its red book capacity, not its data capacity.
This article is talking about the CD from both the physical and the software sides, so putting a precise and unambiguous number in the panel isn't simple. A compromise that alerts the user to the difference might be to specify capacity of a CD as typically up to ~700 MiB (CD-ROM), or 80 mins audio (~800 MiB of red book audio data) and leave it at 1 significant figure of precision. The body of the article gives more precise details of the differences.
We need not provide or suggest unwarranted precision and in such figures and should rise above our personal preference for decimal or binary prefixes (Mega or Mebi) and not try to impose them on the article or get into an edit war. I reverted an edit by an unregistered IP address a short while ago, not because I'm taking sides on the Mega/Mebi issue but because the kilobit/s kilobyte/s was confused B is for Byte, b is for bit, by convention. Dynamicimanyd (talk) 10:50, 29 August 2013 (UTC)

## A question

{{help me}}

Dear editor, My name is Hans Peek and am indeed, as you presumed, the author of the article mentioned in the history under [3]. Thank you for accepting my recent text proposals. I do not know if you can access my article. If not, I can send you a copy of this article.. This article, also describes briefly, the reason of the long period, 1974-1978, it took Philips 'audio' to switch from analog registration to digital. In the period 1969-1987, I was a department head at the Philips research laboratory in Eindhoven. From 1974 on, I and two of my department members got involved in the project group installed by L. Ottens. For me and my department member L. Vries, there was an important reason to choose digital registration instead of analogue. In that case most errors on an optical audio disc could be corrected or masked. However, it took four years for 'audio' to accept this. If you think it is useful for the history of the CD to mention this I can write a brief text proposal?

Best regards,

Hans Peek— Preceding unsigned comment added by Peek (talkcontribs) 15:23, 15 July 2012 (UTC)

Welcome to Wikipedia. I have seen your additions to the article and I have helped them fit into the general style and format of Wikipedia. Thank you for bringing the reference here; it is good information.
What is your concern? Are you worried about this note on your talk page? That sort of note is standard boilerplate for an author who adds his own work to Wikipedia. The conflict of interest in this case is very mild, not worrisome. Your paper that was published by the IEEE is a fine source for this topic.
If you have a specific question to ask, please ask it here. Binksternet (talk) 12:28, 16 July 2012 (UTC)

## Requested move 1

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: page moved. Arbitrarily0 (talk) 02:51, 3 March 2013 (UTC)

Compact DiscCompact disc – "Compact Disc" may be a proprietary term (the article isn't clear on this point), but it's long since become a generic trademark. See, for example, this Ngram. Also check "compact disc" -wikipedia, where the only instances of our capitalization are in titles or proper names. And don't forget, from MOS:CAPS, "Wikipedia avoids unnecessary capitalization." If in doubt, go lowercase. --BDD (talk) 16:11, 22 February 2013 (UTC)

• Support. The topic has become a generic term. Binksternet (talk) 17:37, 22 February 2013 (UTC)
• Note: Please see all previous move discussions linked at the top of this page. Also, MOS:CAPS does not apply here, where as MOS:TM states to capitalize tradmarks. Edokter (talk) — 23:59, 22 February 2013 (UTC)
• Support. It's a generic term, much like cassette tape or floppy disk. Just look at the box at the top of this page. Does it use capitals? I don't think so. It has "compact disc" in lowercase. Also my CD player says "compact disc" on it in lowercase. If it were proper to spell it "Compact Disc" why don't CD players have it in capital? RightGot (talk) 01:56, 23 February 2013 (UTC)
• Support: Has become a generic name. Skinsmoke (talk) 01:44, 25 February 2013 (UTC)
The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

## Requested move 2

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: Not moved. Chamal TC 13:35, 14 April 2013 (UTC)

Compact discCD – CD already redirects here and Compact Disc single and Compact Disc player were changed to CD single and CD player. Unreal7 (talk) 18:07, 30 March 2013 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

## Lacquer layer

'A small amount of lacquer is applied as a ring around the center of the disc, and rapid spinning spreads it evenly over the surface.'

Centripetal force will vary widely from centre to outer edge at any given spin speed, and lacquer viscosity is constant, so the lacquer layer will be far from even Tabby (talk) 15:34, 17 April 2013 (UTC)

## Academic citations for Copy Protection

I have included a citation for a website list of known Copy Protected CDs (mainly found in the UK, but some elsewhere which I remember reading at the time) as this was the only thing a very quick scholar.google.com search ignoring patents, brought up to verify the previous early-2002 information (with citation-needed remark). The original link is now dead but it's available on archive.org's Wayback Machine from 5th December 2012 - I found the link in one of the academic paper's references sections.

There were academic discussions of Sony/BMG copy-protection and root-kit techniques by Halderman/Felten then of Princeton, including a 15th USENIX Security Symposium paper but these did not mention earlier copy protection schemes dating back to 2001. I believe there were reasonably erudite forum discussions on hydrogenaudio.org soon after many of the bad CDs were discovered in the wild, though I haven't yet checked the archives.

Dynamicimanyd (talk) 18:31, 22 July 2013 (UTC)

## Requested move 3

The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the proposal was not moved. As noted in the prior and the discussion below, the name has become thoroughly generic; we would capitalize this as much at this point as we would dry ice, escalator, or yo-yo.--Fuhghettaboutit (talk) 03:33, 12 August 2013 (UTC)

Compact discCompact Disc – Something's not right here. While "compact disc" can be regarded as a generic term, what is it being used for? When people say "compact disc" or "CD", they're referring to the proprietary format (or the family of products, see below)... not a whole lot of generic usage there, other than the simple idea of leaving it in lowercase. This is a lot different from "floppy disk", where the term was never really used as a brand name (there's only "Type 1 Diskette" at best). Using "Compact Disc" or even "CD" would also maintain parity between the various other formats (many of which suggest we should use "CD"!), which is different from the NBA situation because this parity is between the related products themselves, not necessarily the articles about them. It would also maintain parity with "Compact Cassette" (even though it's "generic", "cassette tape" never replaced the name) and "LaserDisc" ("laserdisc" can be used as a generic term), which the CD was named for and can also be considered a "related product" in that sense. There is a consistency problem here, at the very least. Despatche (talk) 23:41, 5 August 2013 (UTC)

Just thought of something. We could use "compact disc" to refer to the basic idea of one, which would fit with the "generic" concept (and I would think most people use "CD" or "compact disc" to refer to the entire family of products in that light); then we could use "Compact Disc" to refer to the original type itself. That... would solve everything, I think. Wow. Too bad "CD" never caught on like "DVD" and co. did, this would be a lot simpler then.
Not sure this all can be applied to LaserDisc so easily; my arguments above would apply to it instead. Despatche (talk) 23:45, 5 August 2013 (UTC)
Reading through some of the really old discussions, I noticed a lot of hubbub over it being a trademark or not. It's not so much about being a "trademark" and more about being an official name (the former is simply a sign of the latter), as prescribed by the creator of the product/s. Speaking of which, we are indeed describing what others prescribe, especially if what I pointed out just above is followed instead.
...Honestly, I'm not sure this is a requested move anymore, I don't know what it is! Split, maybe? Despatche (talk) 23:58, 5 August 2013 (UTC)
• Oppose. The lower case "disc" is warranted because the product name has become generic. Binksternet (talk) 00:06, 6 August 2013 (UTC)
• Oppose per February's RM and Binksternet. Are you confusing the basic idea being generic with genericizing? Yes, "compact disc" could refer to any disc which is compact (the former), but this move was made because "Compact Disc" is a generic trademark at this point. --BDD (talk) 23:08, 6 August 2013 (UTC)
• Oppose per naming conventions. --MicroX (talk) 00:04, 8 August 2013 (UTC)
• Oppose. It is now a generic term. -- Necrothesp (talk) 11:57, 9 August 2013 (UTC)
The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

### A note

A relatively recent book (2009, I don't expect to see much more recent ones about this technology) by Philips authors uses "Compact Disc" to refer to the technology but "compact disc" to refer to an individual disc [3] (they also use the abbreviation CD aplenty for that matter). Someone not using his real name (talk) 08:31, 14 December 2013 (UTC)

## Very confusing image

Individual pits are visible on the micrometre scale

In the Manufacture section, there is an AFM image of the compact disc data surface. The upper half uses color to indicate surface height. Unfortunately, whereas the article describes the surface to have just two types of region -- "pits" and "land" -- there are three distinct colors in the image. If the black color represent pits and the orange color represents the virgin (unexposed, unwritten) surface, what are the white regions along the track between pits? They should be the same shade as the space between tracks. Perhaps some data-processing step caused the white regions, I don't know. The bottom half is difficult to interpret. I think the image should be replaced. Spiel496 (talk) 19:15, 7 July 2014 (UTC)

## comment

I like the article, still have to read over it.Peas345 (talk) 15:30, 13 February 2015 (UTC)

## Red Book Standard - 1980

The Red Book CD-DA standard was published in 1980. The article originally stated that this was "available" in 1979. This is not true. The standard was finalized and published in 1980.

(86.170.95.234 (talk) 01:02, 10 July 2015 (UTC))

Finalized by who? The people who were looking at it in 1979. The proposed standard was being passed around to engineers and executives in the industry, those who would certify it. Binksternet (talk) 02:36, 10 July 2015 (UTC)

Yes, and the fact that the collaboration between Sony and Philips began in 1979 is clear in the text. The standard was PUBLISHED in 1980, and not formally accepted until 1987! The text also reveals that details of the standard were still being worked out in May 1980. Please read the full article. My insert was based on detail further on in the text:

As a result, in 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. Led by engineers Kees Schouhamer Immink and Toshitada Doi, the research pushed forward laser and optical disc technology that began independently by the two companies.[14] After a year of experimentation and discussion, the task force produced the Red Book CD-DA standard. First published in 1980, the standard was formally adopted by the IEC as an international standard in 1987, with various amendments becoming part of the standard in 1996.

Please excuse different IP - I have a "floating" IP address.

(86.170.95.61 (talk) 16:13, 10 July 2015 (UTC))

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## The first commercially released CD album

I've always heard that the first compact disc was a Billy Joel CD.

I found an article that mentions it here...

The CD turns 30: The first player and album were released today in 1982

...and that page references this source (at the Internet Archive)...

Sony Global - Sony History

Wkrick (talk) 15:56, 12 September 2015 (UTC)

It's a myth. There were 50 titles released simultaneously on October 1st, 1982. 52nd Street just had the lowest catalog number. —Torc. (Talk.) 23:11, 2 June 2016 (UTC)
Here are some additional sources about the first batch of commercial CDs: a list of the first 50 titles, all realeased on Oct 1, 1982, "Sony" by John Nathan, PC World article, and Independent UK article. The Billy Joel 52nd Street myth frequently reappears, especially in the Billy Joel and 52nd Street (album) articles, so we need to keep an eye on those so we can finally kill this piece of fiction. —Torc. (Talk.) 19:29, 13 June 2016 (UTC)

## Is it really 700 MiB for audio?

I did some calculations to see how many bytes 80 minutes of uncompressed PCM uses:

(16*2*44100*60*80)/(8*1024*1024) = 807.5 MiB

16 bits per sample, there are 2 channels, there are 44100 samples per second, each minute has 60 seconds, CD holds 80 minutes, 1 byte= 8 bits, 1MiB = 1024 KiB and 1KiB = 1 byte

As you can see I arrived at a value different than the 700 MiB that Wikipedia says. Is it because audio CDs have to worry less about redundancy, so they can hold more data? Did I make a mistake in my calculations? Or is the explanation another entirely? Can anyone clarify?

Adonis_DS (talk) 18:25, 4 January 2016 (UTC)

Yes, audio CDs have one less "layer" of error correction, so they hold 2352 bytes of end-use audio data per sector instead of 2048 bytes as in data CD. In addition the "80 minute" and "700 MB" figures are approximations, and both are actually outside the standards, which call for 650 MiB or about 74 minutes. The "80 minutes" and "700 MiB" are achieved by using a slightly tighter track pitch than the standard allows. Jeh (talk) 19:47, 4 January 2016 (UTC)
Thanks! Adonis_DS (talk) 7:47, 5 January 2016 (UTC)

## Numbers in the Physical Details section

"Each pit is approximately 100 nm deep by 500 nm wide, and varies from 850 nm to 3.5 µm in length""

Where do these numbers come from? In EFM scheme, for example, where pit lengths are between 3S-11S and the single-bit length S=0.278µm, the aforementioned values are NOT true.

## Proper noun?

The capitalization in the article name indicates compact disc is not a proper noun. The lead uses title case and so presumably believes otherwise. Capitalization is inconsistent throughout the rest of the article. Which is it? I'd do something WP:BOLD but I don't have a good track record making these calls. ~Kvng (talk) 15:59, 9 August 2016 (UTC)

Imho, it's a proper noun and should be capitalized. A "compact disc" is just about any flat, circular object that can be described as compact. The "Compact Disc" standard is what this page is about. --Zac67 (talk) 17:00, 9 August 2016 (UTC)
I've always seen "compact disc" written in lowercase. It's written in lowercase on this CD player https://en.wikipedia.org/wiki/CD_player#/media/File:CDP101a.jpg 2602:306:3653:8920:8845:B1A5:A7FD:157F (talk) 19:25, 9 August 2016 (UTC)
Actually, it's spelled "COMPACT disc DIGITAL AUDIO" on the CDP-101... --Zac67 (talk) 19:57, 9 August 2016 (UTC)
For our purposes here, it doesn't matter how others style it, it just matters what kind of noun it is. See Wikipedia:Manual_of_Style/Titles#Capital_letters. ~Kvng (talk) 21:09, 9 August 2016 (UTC)