Last-modified: 2000/09/21
Version: 2.22
This section covers recordable CD media.
The basic building blocks of CD-R media are cyanine dye, which is cyan blue in color, and phthalocyanine dye, which is more or less colorless. The reflective layer is either a silvery alloy, the exact composition of which is proprietary, or 24K gold.
There are gold/gold, green/gold, silver/blue, and silver/silver CD-Rs. The apparent color is determined by the color of the reflective layer (gold or silver) and the color of the dye (cyan or colorless). For example, green/gold discs combine a gold reflective layer with a cyan-colored dye, resulting in a gold appearance on the label side and a green appearance on the writing side.
Many people have jumped to the conclusion that "silver" discs are made of silver, and have attempted to speculate on the relative reflectivity and lifespan of the media based on that assumption. Until an industry representative issues a statement concerning the actual composition, it would be unwise to assume that the reflective layer has any specific formulation.
Taiyo Yuden produced the original gold/green CDs, which were used during the development of CD-R standards. Mitsui Toatsu Chemicals invented the process for gold/gold CDs. Silver/blue CD-Rs, manufactured with a process patented by Verbatim, first became widely available in 1996. According to the Ricoh web site, the silver/silver "Platinum" discs, based on "advanced phthalocyanine dye", were introduced by them in 1997. They didn't really appear on the market until mid-1998 though.
See section (7-3) for vague details on who manufactures what.
The reason why there are multiple formulations is that the materials and process for each are patented. If a new vendor wants to get into the CD-R market, they have to come up with a new combination of materials that conforms to the Orange Book specifications.
Some CDs have an extra coating (e.g. Kodak's "Infoguard") that makes the CD more scratch-resistant, but doesn't affect the way information is stored. The top (label) side of the CD is the part to be most concerned about, since that's where the data lives, and it's easy to damage on a CD-R. Applying a full circular CD label will help prevent scratches.
http://www.mitsuigold.com/ has some info on MTC media. You can visit http://www.ricohcorp.com/press/platinum2.htm for a press release concerning Ricoh's "platinum" media.
An EMedia Professional article discussing the composition of the newer discs is online at http://www.emediapro.net/EM1998/starrett10.html.
CD-RW discs have an entirely different composition. The data side (opposite the label side) is a dark silvery gray that is difficult to describe.
Yes. There are four factors to consider:
Some people have found brand X CD-R units work well with media type Y, while other people with the same unit have had different results. Recording a disc at 4x may make it unreadable on some drives, even though a disc recorded at 2x on the same drive works fine.
To top it all off, someone observed that discs burned with one brand of CD-R weren't readable in cheap CD-ROM drives, even though the same kind of media burned in a different device worked fine. The performance of any piece of media is always a combination of the disc, the drive that recorded it, and the drive that reads it.
A number of specific discoveries have been posted to Usenet, but none of them are conclusive. Many people have reported that Kenwood CD players don't deal with CD-Rs very well, while Alpine units play nearly everything.
Some users have found that the *quality* of audio recordings can vary depending on the media. Whatever the case, if you find that CD-Rs don't sound as good as the originals, it's worthwhile to try a different kind of media or a different player. See section (4-18) for other ideas.
One final comment: while there are clearly defined standards for CD-R media, there are no such standards for CD and CD-ROM drives -- other than that they be able to read CDs. It is possible for media to be within allowed tolerances, but be unreadable by a CD-ROM drive that can handle pressed discs without trouble. All you can do in this sort of situation is find a better-quality CD or CD-ROM drive, or switch to a brand of media whose characteristics are on the other side of the tolerance zone.
Taiyo Yuden made the first "green" CDs. They are now manufactured by TDK, Ricoh, Kodak, and probably several others as well.
Mitsui Toatsu Chemicals (MTC) made the first "gold" CDs. They are now manufactured by Kodak and possibly others as well.
Verbatim made the first "silver/blue" CDs.
Most CD-R brands (e.g. Yamaha and Sony) are actually made by a handful of major disc manufacturers. Attempting to keep track of who makes what is a difficult proposition at best, since new manufacturing plants are being built, and resellers can switch vendors. See section (2-33) for notes about identifying the source of a CD-R.
There is no "best" media for all recorders. You can't tell how well a disc will work just by looking at it; the only way to know is to put it in *your* recorder, write a disc, then put it in *your* reader and try it. Statements to the effect that "dark green" is better than "light green" are absurd. Some discs are more translucent than others, but that doesn't matter: they only have to reflect light in the 780nm wavelength, not the entire visible spectrum.
It may be a good idea to start by selecting media that is certified for your recorder's desired write speed. This is particularly important for CD-RW discs, which won't be written faster than the disc is rated for, regardless of the top speed of the drive. Using 8x-certified CD-R media when recording at 8x isn't a bad idea, but doesn't seem to be essential. See section (3-31) for some other remarks about recording speed.
The Orange Book standard was written based on the original "green" discs from Taiyo Yuden. "Green" media is more forgiving of marginal read/write power variations than "gold", making them easier to read on some drives. TDK's media has been a popular choice for some time.
"Gold" media manufacturers claim it has a longer lifespan and will work better in higher speed recording than "green" discs. Mitsui's gold/gold discs are recommended by some vendors, and in some informal and unscientific tests were more compatible with car CD players than Kodak gold or TDK green discs. The response to Mitsui's "platinum" media has also been favorable. Different test labs will tell you different things.
See http://www.cd-info.com/CDIC/History/Commentary/Parker/stcroix.html for some notes on low-level differences between media types.
There is no advantage to using expensive "audio CD-Rs". There is no difference in quality between consumer audio blanks and standard blanks from a given manufacturer. If you have a consumer audio CD recorder, you simply have no other choice. There is no way to "convert" a standard blank into a consumer audio blank. See section (5-12) for notes on how you can trick certain recorders into accepting standard blanks.
Trying samples of blanks is strongly recommended before you make a major purchase. Remember to try them in your reader as well as your writer; they may not be so useful if you can't read them in your normal CD-ROM drive.
Maxell's CD-R media earned a miserable reputation on Usenet. In April '97 Maxell announced reformulated media that seemed to work better than the previous ones. It appears they may no longer make their own media.
Some good technical information is available from http://www.mscience.com/.
BLER measurements for a variety of recorders and media is in a big table on http://www.digido.com/meadows.html.
See also "Is There a CD-R Media Problem?" by Katherine Cochrane, originally published in the Feb '96 issue of CD-ROM Professional.
There doesn't seem to be a clear answer for CD-RW. The rest of this section applies to CD-R.
The manufacturers claim 75 years (cyanine dye, used in "green" discs), 100 years (phthalocyanine dye, used in "gold" discs), or even 200 years ("advanced" phthalocyanine dye, used in "platinum" discs) once the disc has been written. The shelf life of an unrecorded disc has been estimated at between 5 and 10 years. There is no standard agreed-upon way to test discs for lifetime viability. Accelerated aging tests have been done, but they may not provide a meaningful analogue to real-world aging.
Exposing the disc to excessive heat, humidity, or to direct sunlight will greatly reduce the lifetime. In general, CD-Rs are far less tolerant of environmental conditions than pressed CDs, and should be treated with greater care. The easiest way to make a CD-R unusable is to scratch the top surface. Find a CD-R you don't want anymore, and try to scratch the top (label side) with your fingernail, a ballpoint pen, a paper clip, and anything else you have handy. The results may surprise you.
Keep them in a cool, dark, dry place, and they will probably live longer than you do (emphasis on "probably"). Some newsgroup reports have complained of discs becoming unreadable in as little as three years, but without knowing how the discs were handled and stored such anecdotes are useless. Try to keep a little perspective on the situation: a disc that degrades very little over 100 years is useless if it can't be read in your CD-ROM drive today.
By some estimates, pressed CD-ROMs may only last for 10 to 25 years, because the aluminum reflective layer starts to corrode after a while.
One user was told by Blaupunkt that CD-R discs shouldn't be left in car CD players, because if it gets too hot in the car the CD-R will emit a gas that can blind the laser optics. However, CD-Rs are constructed much the same way and with mostly the same materials as pressed CDs, and the temperatures required to cause such an emission from the materials that are exposed would melt much of the car's interior. The dye layer is sealed into the disc, and should not present any danger to drive optics even if overheated. Even so, leaving a CD-R in a hot car isn't good for the disc, and will probably shorten its effective life.
See also http://www.cd-info.com/CDIC/Technology/CD-R/Media/Longevity.html, especially http://www.cd-info.com/CDIC/Industry/news/media-chronology.html about some inaccurate reporting in the news media.
http://www.cdpage.com/dstuff/BobDana296.html has a very readable description of CD-R media error testing that leaves you with a numb sense of amazement that CD-Rs work at all. It also explains the errors that come out of MSCDEX and what the dreaded E32 error means to a CD stamper. Highly recommended.
There are 21-minute (80mm/3-inch), 63-minute, 74-minute, and 80-minute CD-Rs. These translate into data storage capacities of 184MB, 553MB, 650MB, and 700MB respectively (note these numbers are approximate). See section (7-14) for more about 80mm CD-Rs, and section (3-8-1) for some notes on 80-minute blanks.
Typical 74-minute CD-Rs are advertised as holding 650MB, 680MB, or even 700MB of data. The reality is that they're all about the same size, and while you may get as much as an extra minute or two depending on the exact construction, you're not usually going to get an extra 30MB out of a disc labeled as 74-minute media. See section (3-8-3) for information on writing beyond a disc's stated capacity.
Folks interested in "doing the math" should note that only 2048 bytes of each 2352-byte sector is used for data on typical (Mode 1) discs. The rest is used for error correction and miscellaneous fields. This is why you can fit 747MB of audio WAV files onto a disc that holds 650MB of data.
It should also be noted that hard drive manufacturers don't measure megabytes in the same way that CD-R and RAM manufacturers do. The "MB" for CD-Rs and RAM means 1024x1024, but for hard drives it means 1000x1000. Keep this in mind when purchasing a hard drive that needs to hold an entire CD. A data CD that can hold 650 "RAM" MB of data holds about 682 "disk" MB of data, which is why many CD-Rs are mislabeled as having a 680MB capacity. (The notion of "unformatted capacity" is a nonsensical myth.)
Spelled out simply:
74 minutes == 333,000 sectors == 650.3MB CD-ROM == 746.9MB CD-DAThe NIST is considering the use of different names for powers of 2, which would avoid this ambiguity and disappoint lots of marketing folks. See http://physics.nist.gov/cuu/Units/binary.html.
80 minutes == 360,000 sectors == 703.1MB CD-ROM == 807.4MB CD-DA
Some programs, such as Easy-CD Pro 95, will tell you the exact number of 2K blocks available on the CD. (With Easy-CD, put a blank disc in the CD-R and go to the "Disc Info / Tools" menu item.) It's difficult to draw conclusions from the results though. An article in the June issue of _EMedia Professional_ found that not only does disc capacity vary from brand to brand and batch to batch, it may even vary depending on which model of recorder is used to examine the disc.
An informal survey conducted by one user found that the deviation between the largest and smallest CD-R was about 3500 blocks (47 seconds, or 7MB), which while not inconsequential is nowhere near the difference between 650MB and the 680MB or 700MB figures quoted by some manufacturers. All discs had at least 333,000 blocks, as required by the Red Book specification. (Before you ask which discs held the most data so you can run out and buy them, I should mention that the person doing the survey had trouble mounting some of the higher-capacity discs. Getting those few extra seconds may cost you in other ways.)
http://www.cdmediaworld.com/ has a fairly detailed listing of how much data different brands of media will actually hold. Again, bear in mind that different batches of the same media may have different capacities.
The PCA (Program Calibration Area), PMA (Program Memory Area), TOC (Table of Contents), lead-in, and lead-out areas don't count against the 74-minute rating on single-session CDs. You really do get all the storage that the disc is rated for. On standard MODE 1 discs that aren't using packet writing, there is no "formatting overhead". Bear in mind, however, that the "cluster" size is 2K, and that the ISO-9660 filesystem may use more or less space than an MS-DOS FAT or HFS filesystem, so 650MB of files on a hard disk may occupy a different amount of space on a CD.
On a multisession disc, you lose about 23MB of space when the first session is closed, and about 14MB for each subsequent session. A common mistake when writing multisession CDs is to overestimate the amount of space that will be available for future sessions, so be sure to take this into account.
Pressed aluminum CDs are also supposed to hold no more than 74 minutes of audio, but are often tweaked to hold more (see section (3-8)). This can make life interesting when attempting to copy CDs. BTW, to convert blocks to seconds, divide the number of blocks by 75. If your blanks have 333,000 blocks, they have 4440 seconds, which is exactly 74 minutes.
Some packet-writing solutions will take a large bite out of your available disc space. For example, if you use Adaptec DirectCD 2.x with CD-RW media, it uses fixed-length packets. This allows random file erase, which means that when you delete a file you actually get the space back, but you're reduced to about 493MB after formatting the disc. More recent versions can get closer to 531MB. (You can create a CD-RW with variable-length packets by formatting a CD-R with DirectCD and then doing an image copy from CD-R to CD-RW. You regain the space but lose the ability to do random file erase.)
Only if you're careful. The adhesives on some labels can dissolve the protective lacquer coating if the adhesive is based on a solvent that the lacquer is susceptible to. Asymmetric labels can throw the disc out of balance, causing read problems, and labels not designed for CDs might bubble or peel off when subjected to long periods of heat inside a CD drive. Similarly, the ink in some kinds of pens may damage the top coating of the disc.
Specific information can sometimes be found on the back of the jewel case that the discs come in. Old TDK CDR-74 discs had the following warning:
"[...]Other brands say "use a permanent felt-tipped pen" or words to the effect that the ink shouldn't smudge. The most important part is to use a felt tip pen and not a ball-point, because the top layer can be delicate.2. Do not attach labels or protective sheets, or apply any coating fluids to the disc.
3. When writing titles and other information on the label (gold) side of the disc, these should be written in the printed area using an oil-based felt-tipped pen.
[...]"
There are pens recommended specifically for writing on CD-Rs. Examples include the Dixon Ticonderoga "Redi Sharp Plus", the Sanford "Powermark", TDK "CD Writer", and Smart and Friendly "CD Speed Marker". Some of these are relabeled Staedtler Lumocolor transparency markers, which are water-based. Never use a solvent-based pen on a CD-R.
Many people have had no problems with the popular Sanford "Sharpie" pens, which are alcohol-based. Other people say they've damaged discs by writing on them with a Sharpie. In any event, the Ultra Fine pen looks almost sharp enough to scratch, so sticking with the Fine Point pen is recommended.
So long as you use the right kind of pen, it's okay to write directly on the top surface of the CD, label or no. If the prospect makes you nervous, just write in the clear plastic area near the hub, or only use discs with a printable top surface.
Whatever you do, don't try to peel a label off once it's on. You will almost certainly pull part of the recording layer off with the label. If you're going to label a disc, do it immediately, so you can make another copy if the label doesn't adhere smoothly. Any air bubbles in the label that can't be smoothed out immediately are going to cause trouble.
Only use labels made specifically for recordable CDs. ProSource Sales & Marketing, Inc. (http://www.prosourcesales.com/accessories.html) sells labels and an applicator that are reputed to work well. See also http://www.neato.com/ for information on the NEATO CD-Label kit, and http://www.labelcd.com/ for the CD Stomper Pro. If you speak Italian, try http://www.ufocd.com/. Information on The Gizmo is available from http://www.greatgizmos.com/. http://www.surething.com/ has software that works with most paper types.
Buy some labels, put them on some discs, leave them someplace warm, and see if they peel off. If they do, you'll need a different kind of media or a different kind of label. Some labels don't adhere very well unless they're attached to a disc with a plain lacquer surface on top.
You can also buy printers that will write directly onto discs with a printable surface. One example is http://www.primeratechnology.com/, which now handles the FARGO CD-R label printers.
A wealth of information on CD-R labeling options can be found here: http://www.cd-info.com/CDIC/Technology/CD-R/Labeling/
Sony's http://www.sonydadc.com/ web site has a "Downloads & Templates" section with artwork that my prove useful. You can find most CD-related logos on the site (try http://www.sonydadc.com/pr_template.asp, click on "Logos" for common formats). Some are also available from http://www.licensing.philips.com/cdsystems/cdlogos.html.
Mike Richter's CD-R primer has a very nice page on labeling discs. See http://resource.simplenet.com/primer/labels.htm.
It is important to keep the CD balanced, or high-speed drives may have trouble reading the disc. According to one report, a disc that had a silk-screened image on the left side of a CD-R (leaving the right half of the disc blank) was unreadable on high-speed drives due to excessive wobbling. Most label kits come with a label-centering device, usually something trivial like a stick that's the same width as the hole in the middle of the CD.
Avery's CD-R labels became quietly unavailable in October 1997. The rumor is that the adhesive caused data corruption problems, so Avery recalled them. There are indications that the adhesive would fail on some discs and start to lift off within a short period of time. If you have Avery labels (#5824) purchased before this date, you should avoid using them. The labels being produced now don't have this problem.
Disclaimer: I'm not recommending you put a CD into a microwave. CDs may contain metals that will cause your microwave to arc, destroying the microwave emitter (see cautions about metal objects in the manual for your microwave). Don't try this at home. Better yet, don't try this at all.
The basic process is, take a disc that you don't want anymore, and put it shiny-side-up on something like a mug of water so it's nowhere near the top, bottom, or sides of the microwave. (Actually, you may want to leave it right-side-up if the disc doesn't have a label, because the foil is closest to the top of the CD.) I'm told it is important to put something in the cup to be on the safe side. Try to center it in the microwave. Turn off the lights. Program the microwave for a 3-second burst on "high", and watch the fireworks.
Performing this operation on replicated CDs results in blue sparks that dance along the CD, leaving fractal-ish patterns etched into the reflective aluminum. For those of you not with the program, this also renders the CD unreadable.
Trying this with a green/gold CD-R gives you a similar light show, but the destruction patterns are different. While pressed CDs and CD-RWs don't develop consistent patterns of destruction, CD-Rs tend to form circular patterns, possibly because of the pre-formed spiral groove.
On a different note, CD-Rs seem to smell worse, or at least they start to smell earlier, then replicated CDs. The materials used are non-toxic ("cyanine" comes from the color cyan, not from cyanide), but breathing the fumes is something best avoided.
For the curious, here's a note about why they behave like they do:
"The aluminum layer in a CD-ROM is very thin. The microwave oven induces large currents in the aluminum. This makes enough heat to vaporize the aluminum. You then see a very small lightning storm as electric arcs go through the vaporized aluminum. Within a few seconds there will be many paths etched through the aluminum, leaving behind little metalic islands. Some of the islands will be shaped so that they make very good microwave antennas. These spots will focus the microwave energy, and get very hot. Now you will see just a few bright spots spewing a lot of smoke. The good part of the light show is over, turn off the oven.I suspect that if you leave the oven going much longer, the CD-ROM will burst into flame. This will smell very bad and may do bad things to your oven and house. Don't do it."
-- Paul Haas (paulh@hamjudo.com), on http://hamjudo.com/notes/cdrom.html
Dreamcast GD-R discs come out just like CD-R, but DVD-R is a whole different experience.
If the disc wasn't closed, you can write more data in a new session. If the disc was closed, or was nearly full when the write failed but is still missing important data, then its use as digital media is over.
However, that doesn't mean it's useless. Here are a few ideas:
In one carefully controlled experiment it was determined that CD-Rs behave differently from pressed CDs when you slam them edge-on against the ground. The aluminum ones will chip (once you throw them hard enough, otherwise they just bounce) and create silver confetti. The gold one I tried chipped and the gold layer started peeling, leaving little gold flakes everywhere. One user reported that a Verbatim blue CD developed bubbles even though the plastic was intact. More experimentation is needed (but not around pets, small children, or hard-to-vacuum carpets).
On a different tack, some CD-Rs don't hold up well when immersed in water. Try pouring a little water on a disc, then let it sit until it dries. If the top surface scratches off more easily afterward, you need to be careful around moisture. Silver/blue Verbatim discs seem particularly sensitive.
One comment about snapping discs in half with your fingers: use caution. Depending on the disc and how you break it, you may end up with lots of sharp polycarbonate slivers flying through the air. Wear eye protection, be aware of people around you, and be sure to clean up all the plastic shards afterward.
If you have far more coasters than you want to play with, consider recycling them. GreenDisk, at http://www.greendisk.com/, recycles several different kinds of media.
There are many vendors. A few are listed below.
Incidentally, you have a lot of choices when it comes to CD packaging. There are single-disc jewel cases, double-sized doubles, single-sized doubles, triples, quads, sextuples, plain colors, neon colors, paper envelopes, Tyvek envelopes, cardboard sleeves, clear jewel cases with black trays, clear jewel cases with built-in trays, CD pockets for use in three-ring binders, and on, and on.
If you can imagine it, it's probably up for sale.
Some URLs to start with:
http://www.bagsunlimited.com/
http://www.tape.com/cdr.html
http://www.xdr2.com/cd-jewel.htm
http://www.cdroutlet.com/
http://www.desktopsupplies.com/dps/cdromproducts.html
http://www.discmarket.com/
Simply put, it's a CD-R disc with nothing printed on the top surface. Some people need "plain" discs that they can print on, or simply like them for the aesthetic value. There is no difference in quality or capacity.
If you scratched the top (label) side of a CD-R, and it no longer works, your disc is toast. (If you scratched it, and it still works, copy the data off while you still can.)
If you scratched the bottom side, then all you've done is etch the polycarbonate (plastic), and it can be repaired like any other CD. A common misconception is that the data is on the bottom, but if you examine it carefully you will see that the data is beneath the label. The laser reads the data through the polycarbonate layer, and if the layer is scratched the laser will refract onto the wrong part of the disc.
For small or radial scratches, the error correction in the CD format will allow the disc to continue working, but if there's too much disruption you will get audible glitches or CD-ROM driver errors.
If the disc works some of the time, you can "repair" it by copying it onto a new CD-R disc. If the disc is always unreadable, or is copy protected, you will need to repair the disc itself.
One product that may be useful is Wipe Out! (http://www.cdrepair.com/), a chemical abrasive that allows you to reduce scratches. Others include Scratch Suppressor from http://www.cdrestore.com/ and Discwasher from http://www.recoton.com/docs/disc/1-4.html.
The Repair FAQ at http://www.repairfaq.org/ has a section on repairing scratched CDs. Find the "Compact Disc Players and CDROM Drives" section, and skip down to 4.10 and 4.11.
Some people have suggested using plastic polishes or "fine cut" paint polishes sold for removing fine scratches on automobiles. These fill in the scratches and create a more optically consistent surface. Fine metal polishes may also work, and some people claim that plain old white toothpaste does the trick. There is some chance that the filler material will fall out over time, rendering the disc unreadable once again, and possibly gunking up your CD-ROM drive along the way. If you want to fill in the scratches, you should make a copy of the contents to a new disc as soon as possible, and stop using the original.
In the United States, a distinction is made between "consumer digital audio" media and data media. You have to pay extra for consumer audio CD-R blanks and DAT tapes, and the music recording industry gets a piece on the assumption that the media will be used to hold commercially recorded material.
Canada has gone a step farther, by placing a levy upon *all* media capable of storing audio. Even the "data" CD-R blanks, which don't work in consumer audio CD-recordable decks, are subject to the levy.
Some web sites with more information:
http://neil.eton.ca/copylevy.shtmlSee also http://www.cb-cda.gc.ca/news-e.html for a 1999/12/17 announcement that the Levy has gone into effect.
http://pcbuyersguide.com/hardware/storage/cdr-levy.html
The 80mm CD didn't catch on everywhere. In some markets, notably the USA, the smaller discs are rarely seen. The 80mm CD-R made a brief appearance, and then vanished.
It appears that, because of the growing popularity of home CD recorders, a manufacturer has decided to produce the 80mm media once again. Using them may not be as straightforward as could be hoped. Most software will work just fine, because all CD-Rs have slightly different capacities, especially when you consider 63-minute, 74-minute, and 80-minute blanks. The problems stem from their physical dimensions.
If you have a caddy-based recorder, you will have a problem: while trays have two different rings for 80mm and 120mm discs, caddies don't. According to the Yamaha CDR-102 manual, there is a "Disk Adaptor", referenced as part #ADP08, that sits in the caddy and keeps the disc properly positioned. A device that performed a similar function used to be sold by music stores so that standard players could handle 80mm CD-singles; it looks like a plastic donut that clips onto the disc.
If you have one of these, great. If you don't, you may have difficulty finding them. You will likely have even worse luck figuring out how to play an 80mm disc on a "slot in" CD-ROM drive -- the kind where you push the disc into a slot, and it slurps it up.
A less common issue with 80mm discs has to do with playback. A loose sheet included with the CDR-100/102 "CD Expert" manual states:
"An 8-cm disc recorded at normal speed on the CD Expert may not playback correctly on some manufacturer's CD-ROM drives. This is likely on drives that have a playback PLL (phase lock loop) bandwidth of 1.5 kHz. Most drives, however, have a playback PLL bandwidth of 2.5 kHz, in which case this is not a problem."The final discouragement for 80mm discs is that they only hold 21 minutes of audio (about 95250 sectors on Ritek silver-blue discs, or about 186MB), but at present cost more than their full-sized counterparts. They are an interesting curiosity, and a cute gift when placed in a miniature jewel case, but little more.
[ On a personal note: my Plextor 8/20 refuses to accept 80mm discs when I put them in the tray. I was able to use them with a (caddy-load) Yamaha CDR-102 when I put the discs in a CD-single caddy adapter. It turns out that the Plextor 8/20 will write to the discs when the caddy adapter is used for it as well. There seems to be some problem with the Plextor's mechanics when the disc is resting in the 80mm tray. I found the discs at http://www.cdroutlet.com/; others have used http://www.octave.com/. ]
You can find CD-ROMs in many interesting shapes, including ovals and rectangles. These are functional CD-ROMs that are, for example, the same size and shape as a traditional business card (well, a really thick business card). They can have your name and contact information printed on the front, and can hold a modest amount of data, typically about 40MB.
Recordable CD-R business cards are available as well.
As with 80mm CDs (see section (7-14)), you may have trouble playing these "discs" on CD-ROM drives that use caddies or have a "slot-in" design.
Some net.vendors (there are many others):
http://www.cdshapes.com/For information about a 57.5mm disc with 80mm "wings", see http://microdiscs.de/.
http://www.pocketcd.com/
http://www.cddigitalcard.com/
http://www.sculptedcd.com/
http://www.avomedia.com/record/index.html
http://www.superduperdisc.com/
http://www.cdroutlet.com/
http://www.xdr2.com/
http://www.shimad.com/
http://www.home-run.com/
http://www.cdcardusa.com/
Cutting a CD-R disc into a different shape isn't recommended, because the recording layer tends to delaminate easily once the seal has been broken. Some CD-Rs have appeared in Japan that use a 120mm polycarbonate disc with an 80mm recordable area. This allows the outer polycarbonate to be cut into interesting shapes without affecting the recordable area. Some pictures are available on http://www.fadden.com/cdrpics/.
What follows are some personal notes on CD-recordable business cards.
I bought five from www.cdroutlet.com for about $3 each. According to CD-R
Media Code Identifier, the essential facts are:
Nominal Capacity: 51.219MB (05m 51s 49f / LBA: 26224)The discs are gold in color, and look like an 80mm disc that was squared off across the top and bottom. They come in clear plastic envelopes that are slightly larger than the discs themselves. Total size is 80mm long and 60mm wide, which is a little off from the standard business card (88mm x 51mm) but not by much.
ATIP: 97m 1As 55f
Disc Manufacturer: Lead Data Inc.
Dye: Pthalocyanine (Type 5)
As with 80mm CD-Rs, my Plextor 8/20 rejected them unless I put them in an 80mm caddy adapter. The adapter doesn't work very well, since it's only holding the disc on two points, but it worked well enough.
I grabbed a local copy of my web page, threw on an autorun.inf and a copy of shellout.exe, and wrote it to the disc with disc-at-once recording. The recorder got upset while writing the leadout, and ECDC (3.5c) reported some fatal errors, but the disc had already been closed enough to be readable in the two CD-ROM drives tried. It's possible that the slight looseness in the caddy adapter caused problems... on future attempts I will try to fasten the disc a little more securely.
The use of these discs as business cards presents some difficulties. If you look at the picture on http://www.fadden.com/cdrpics/, you can see that the disc has the same clear hub as a standard disc, which doesn't give you much of a solid background for writing. All is not lost, however: there are other cards with ink-jet printable surfaces, and adhesive business card labels are now available.
The easiest way is to drag something sharp across the top and watch what happens. If you'd like to be able to use the disc afterward, there are some non-destructive ways too.
In some cases it's easy to tell, e.g. the color is slightly off or there are two different shades of silver. The written areas on a CD-R look slightly different from unwritten areas. A silver CD-R that has been written to capacity is nearly indistinguishable from a pressed disc though.
You can get a definitive answer with CD-R Media Code Identifier (6-2-9). Put the disc into a CD recorder and query it. Pressed discs will say "no information". Some CD recorders might have trouble finding the ATIP after the disc has been closed, so do some tests with known discs before jumping to any conclusions.
"Consumer" stand-alone audio CD recorders require special blanks. See section (5-12) for details. There is no difference in quality or composition, though it's likely that "music" blanks are optimized for recording at 1x.
Some manufacturers have on occasion marked low-quality data discs as being "for music". Make sure that, if you need the special blanks, you're getting the right thing.
The CD-Rs required by "consumer" stand-alone audio recorders ( section (5-12)) are more expensive than the standard "data" CD-Rs. Converting a standard blank into a consumer-audio blank is like converting lead to gold, in two ways: it would save a lot of money, and it's impossible.
CD-Rs have some information pressed into them that cannot be altered. One such tidbit is the Disc Application Flag, which tells the recorder what sort of blank you've inserted.
There are ways to trick a recorder into accepting other kinds of blanks (some of which are mentioned in section (5-12)), but there is no way to disguise the blank itself.
FAQ Copyright © 2000 by Andy McFadden. All Rights Reserved.