source file: mills2.txt Date: Thu, 5 Sep 1996 16:54:41 -0700 Subject: mclaren's opinion on CDR (fwd) From: John Starrett This is the text of email to me from Dana Parker in response to mclaren's post on CD Recordable which I forwarded to her. mclaren- I hardly know where to begin to correct the misinformation, myth, and utter nonsense in your message about CD-R technology. Dvorak on CD-R: Anyone who placed his or her trust in what John Dvorak says about CD related technology would be CD-ROM-less today. In 1989, Dvorak wrote a column about CD-ROM technology that was just as negative - and just as wrong -as his March 1996 column about CD-R. There is a reason behind this animosity on Dvoraks part - it took him six months to successfully install his first CD-ROM drive, by his own admission. As a result, he dismissed the entire technology as worthless, which says more about Dvorak than it does about CD-ROM or any of its related technologies. Lets take your claims one-by-one. 1. The problem with the writeable CD technology is that you have to make an `image' to be written to the disk. If you want to back up 650 MB, you want to have another 650 MB on your hard disk empty to store the image, which is then transferred to the CD-R. ---False. You have the option, supported by most if not all CD-R software packages,to record "on-the-fly" from a virtual image. A virtual image takes from 1% to 5% of the space of the data to be recorded, depending on the software. Creating a virtual image is virtually transparent to the user - you drag and drop the files to be included, then click on record. 2. You get *one shot at writing to the disk* from beginning to end. You can do multiple sessions, but that's a *real hassle too.* ---False. When Dvorak says something is a "real hassle", what hes really saying is "this is something I dont understand and wont spend five minutes figuring out, let alone attempt to explain to you". Again, depending on the software, creating multiple sessions is a simple drag-and-drop, point-and-click operation. Its not rocket science. 3. If there's a glitch, brownout, operating system hiccup, horribly fragmented file, or any number of things, then the CD doesn't get burned, and you end up with a *blown session.* These are common, and *the result is a totally useless disk* that must be discarded. ---False. Dvorak is right that any of these factors, or more likely, a combination of them, can ruin a recording session by causing a buffer underrun. It is not, however, a common occurence, it does not necessarily render a disc useless, and it is certainly not unavoidable. In over six years of using CD-R, I have never cut a coaster or had a buffer underrun. It is certainly not unavoidable. In over six years of using CD-R, I have never cut a coaster or had a buffer underrun. 4. It takes a couple of hours to prepare your files to be burned into the disk. If something changes, you have to start over. And if your hard disk isn't fast enough, you can't even burn the disk at all. ---False. You can prepare files for recording on CD-R in a matter of seconds. A large dataset might take longer. A dataset intended for distribution might take longer yet, but only because of normal precautions that would be part of preparing any dataset for distribution: virus checking, defragmentation, directory structure, file placement. Most CD-R manufacturers recommend a minimum hard drive speed of 19 ms. 5. "One vendor told me that the quad-speed CD-ROM writers *were kept off the market* because the system requirements were outrageous, and tolerances for error was nil. ---False. This must have been a vendor of 2x CD-Recorders. 4x CD-Recorders have been on the market since 1993, and they function perfectly well on a 386 with 8MB RAM. ---In short, everything Dvorak says is wrong. 6. The test reported on this forum in which a 15-minute audio file was written to CD-R is, alas, meaningless. The acid test: how often does the drive and disc combo produce a bad burn when a full 680 megs of audio data are written non-stop to CD-R disk? ---Apparently not often enough to prevent numerous state, federal, and city governments as well as legal firms from using CD-R as an archival medium for irreplaceable data, or to prevent hospitals from using it to store permanent medical records, or to prevent Jet Propulsion Laboratories from converting irreplaceable data, or to prevent hospitals from using it to store permanent medical records, or to prevent Jet Propulsion Laboratories from converting their 9-track tape libraries of raw satellite data to CD-R. Apparently not often enough to prevent sales of CD-Recordable drives from increasing by a factor often in the past 12 months, or to prevent dozens of CD-R service bureaus from basing successful businesses on creating quality music and data CD-R discs by the thousands every month for their customers. 7. Reports suggest that the error rate right now is around 60%, depending on the brand of CD-R disc. That is, 6 out of 10 discs produce a bad burn and a blowndisc which must be discarded. ---Id be very interested in seeing those "reports". It would be an amazing contrast to the independent testing being sponsored by organizations such as SIGCAT (Special Interest Group for CD Application Technology), OSTA (Optical Storage Technology Association) and JPL. The OSTA prelimianry test results impressed even those of us who knew CD-R was a reliable storage medium - it showed disc reliability to be greater than 96%, regardless of the disc brand. 8. Worse still, my gearhead friends inform me that the writeable CD technology is so flaky that to get good results, people who burn their own CDROMs must check the grapevine to see which brand name of writeable CD-R disc has a bad error rate this month, and which manufacturer came out with a good batch. One month TDK writeable CD-R discs produced near-100% bad burns, the next month it was Mitsui, the next month Sony... And it changes from one month to the next. You get the idea. ---I get the idea you or your gearhead friends are making this up. As someone who has been burning her own CD-Rs, providing technical support for other CD-R users, and writing about the technology for publication since 1990, I can assure you this does not happen among "people who burn their own CD-Rs". The media is relabeled and distributed by hundreds of companies. There is no way of knowing whether a given disc was made in a certain month, and often there is no way to tell who the original manufacturer was. CD-R users couldn't exchange this information even if they wanted or needed to. The problem these days isn't getting a certain brand of media, it's getting any media at all. There is currently a worldwide shortage of several months' duration, and every CD-R media manufacturer is building new plants and adding production lines to keep up with the increased demand, which far exceeded their wildest expectations. This doesn't sound like evidence of a "flaky" technology to me. 9. Worse still, many CD-R writeable drives will burn discs that other brands of CD-ROM read-only drives cannot read. ---This would be more accurately expressed as "some CD-ROM drives are incapable of reading some CD-R discs." This is not because there is necessarily something wrong with the discs. It?s because some CD-ROM drive manufacturers cut corners and narrow the required parameters within which the drive will read to the point that some CD-R discs - as well as many pressed CD-ROM discs - cannot be read, even though they are within specifications. It is also not attributable to the drives that recorded the discs. Recorders use a built-in Optimum Power Calibration before every writing instance to ensure that what is recorded can be reliably read by any CD-ROM drive or CD audio player that is capable of reading within the full range of disc parameters. 10. Despite all the nonsense about the photoreactive dye lasting 10 years, 20 years, 500 years, or what-have-you, the brutal reality is that CD-R discs don't last very long. A year, maximum. Probably less. ---I have a backup of my hard drive on a CD-R disc recorded in 1990. It?s still good, as are all the other discs I have recorded since then. I have not lost one disc to age. The fact is that CD-R discs will probably last longer than pressed CDs, because they use gold, rather than aluminum, as a reflective layer. Aluminum tends to corrode due to reactions with impurities in the polycarbonate and in the aluminum itself. Gold does not. However long the data on CD-R lasts, whether it is 10 years or 300, the fact remains that CD-R is the most durable medium ever developed for the storage of data, with the possible exception of papyrus sealed in clay jars. 11. Fingerprints are permanent. They cannot be burnished off. Try to do so, and you'll destroy the CD-R because you'll smudge the photoreactive dye. ---Have you ever actually seen a CD-R disc? Fingerprints can be wiped or washed off. I polish off fingerprints on my pants leg. The dye - which is an organic dye polymer sensitive to a certain wavelength of laser - is protected on one side by a 1.2mm thick layer of clear polycarbonate (the same stuff used to make motorcycle helmets); on the other by a thin layer of gold and a UV-cured lacquer, often with an additional layer of protective coating and/or printable surface. Your fingers will never come in contact with the dye layer. 12. The photoreactive dye is laid down in a single continuous spiral track 1/10 the width of a human hair. As the disc endures thermal stress in winter and summer, the single continuous spiral track distorts and finally becomes unreadable. ---The dye polymer is applied via spin coating over the entire surface of the disc. Track pitch is 1.6 micrometers, the same as for pressed CDs, and the track itself is .6 micrometers wide. On an unrecorded disc, the spiral track is in the form of a "wobbled pregroove" molded, as a sinusoidal wave with a .3 micrometer excursion, into the polycarbonate itself. The pregroove guides the recording laser. The spiral track on a recorded disc is composed of optical marks produced by a chemical change and/or degradation in the dye layer. "Thermal stress" is not a factor in data loss as much as prolonged exposure to extremely bright light, which can theoretically, over a period of years, affect the comparative reflectivity of marked and unmarked areas of the disc. 13. If the spiral dye channel is even microscopically off-center, the CD-ROM drive will accumulate so many errors as the drive head runs from the inside toward the outside fo the CD-R disc that the disc will be unreadable. ---The pregroove is molded into the disc and does not change or become distorted. If the molded pregroove is microscopically off-center beyond the allowed parameters, the affected disc will never make it out of the plant, nor will the thousands of other discs pressed from the same mold. 14. Thus, unfortunately, the writeable CD technology is not ready for prime time. I researched the technology 6 months ago:it was dismal. Packet-writing drives are now beginning to become available, but it doesn't seem to have helped the abysmal error rate of the CD-R media, nor has it helped lengthen the ridiculously short lifespan of dye-based CD-R discs once burned. Those of you who are contemplating buying a CD-R writeable drive to burn your own microtonal audio CDs would do well to wait another 3-5 years. Perhaps the technology will have been debugged by then. ---I have been working with and researching CD-R technology for most of the past seven years, and I am forced to conclude that your research is what could more properly be described as "dismal" and plagued by an "abysmal error rate". If you depend on the baseless opinions of has-been PC industry pundits, or the properly be described as "dismal" and plagued by an "abysmal error rate". If you depend on the baseless opinions of has-been PC industry pundits, or the advertisement-driven mainstream PC industry magazines for your information, in fact, Id have to say the appropriate term for your CD-R research is "non-existent" - and your "findings" are glaring proof of that. You and John Dvorak could both benefit from doing some real research on CD-R. I'd hate to think that someone might actually decide not to try CD-R technology because he or she mistakenly thought you actually knew what you were talking about. Regards, Dana J. Parker Contributing Editor/Standards Columnist CD-ROM Professional magazine Co-author, CD-ROM Professional's CD-Recordable Handbook Received: from ns.ezh.nl [137.174.112.59] by vbv40.ezh.nl with SMTP-OpenVMS via TCP/IP; Fri, 6 Sep 1996 02:53 +0200 Received: by ns.ezh.nl; (5.65v3.2/1.3/10May95) id AA23327; Fri, 6 Sep 1996 02:54:35 +0200 Received: from eartha.mills.edu by ns (smtpxd); id XA22930 Received: from by eartha.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI) for id RAA01854; Thu, 5 Sep 1996 17:54:34 -0700 Date: Thu, 5 Sep 1996 17:54:34 -0700 Message-Id: Errors-To: madole@ella.mills.edu Reply-To: tuning@eartha.mills.edu Originator: tuning@eartha.mills.edu Sender: tuning@eartha.mills.edu