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28 Jul 01 - 03:56 PM (#516755) Subject: How Well Do CDs last? From: Ebbie I do a great deal of research from microfilm of old newspapers. Yesterday at the Historical Library in a conversation regarding the potentiality of putting newspaper on CDs rather than microfilm, I was told that CDs don't last well. Is this true? I was under the impression that CDs undergo very little wear, other than misuse or bad storage. Ebbie |
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28 Jul 01 - 04:20 PM (#516764) Subject: RE: BS: How Well Do CDs last? From: Bill D It's not 'wear', it's that the layers of stuff that are put on a CD must be bonded perfectly, in a super clean environment. Early CDs tended to have problems as they learned to improve the manufacturing process. They are better now, but 10 years? 25 years? I don't KNOW how long they will last |
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28 Jul 01 - 05:05 PM (#516772) Subject: RE: How Well Do CDs last? From: George Seto - af221@chebucto.ns.ca Plus with general wear-n-tear, the average CD gets scratched and then becomes useless. Microfilm would still be viewable if it was scratched a bit, and they get a lot of abuse from users. If they could use MO disks similar to that used on Mini-Discs, then it would be no problem. Mini-Discs can't be harmed accidentally. I know there are some computer M-O discs and drives, but the field is in its infancy. Speed and capacity have to be improved upon. |
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28 Jul 01 - 07:23 PM (#516829) Subject: RE: How Well Do CDs last? From: Liz the Squeak Hardly at all with a toddler around, and about 1/4 as long as the original advertising in which they drove a car over one and it still played perfectly. The cat sneezes in the same room as a CD and it is scratched beyond redemption here!! Stick with Mini disks or microfiche/film. LTS |
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28 Jul 01 - 07:52 PM (#516846) Subject: RE: How Well Do CDs last? From: Tweedie I would caution against the small MO discs (Mini-Discs). So many manufacturers are making them now (and sub-contracting their manufacture to the lowest tender) that there are real quality control issues. I have Mini-Discs which just fail completely, or sometimes fail on one Mini-Disc reader but not on another. That's okay for music compilations, but I wouldn't trust them for data/archive.
The biggest problem with CDs is that you are likely to scratch the surface, sooner or later. (somebody-or-other's law states that will happen, no matter how carful you are.) Scientific papers have discussed molecular migration (filling in of the CD's pits over decades of time basically) and also the 'wrong ink' on the top surface chemically affecting the data-carrying layers beneath.
The other consideration is error correction. Our music CDs (many being now 12 years old) may be deteriorating, but error-correction is being applied and our ears can't notice the degredation of quality because it's easy to correct the audio. A 12 year old data CD may not survive as well !
Maybe the answer is to burn replacement CDs every 5 years – a time-consuming option. |
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28 Jul 01 - 09:27 PM (#516896) Subject: RE: How Well Do CDs last? From: Ebbie Interesting. I don't remember ever hearing this discussion before. A friend was telling me the other day that I could burn many, many audio tapes onto a single CD. From what you say, that too is not too smart, huh- audio tapes can be spliced. Thanks, everybody. Ebbie |
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28 Jul 01 - 11:35 PM (#516945) Subject: RE: How Well Do CDs last? From: JohnInKansas A fairly recent discussion of the stability of data storage media appeared (within the last year?) in "PC Magazine." The consensus of media manufacturers was that data stored on CDs - archived and not in constant use - can be expected to be well over 20 years, and perhaps the CD data could last longer than we will. An important factor is that an ARCHIVE set should be maintained in proper storage, and would be used only for the occasional production of the MASTER set(s), which would be used in turn for the production of the media used for the day-to-day distribution of data (the DISTRIBUTION sets). Since CDs for mass data storage haven't been around that long, there is a degree of uncertainty, but some testing has been done (accelerated aging via temperature cycling, etc.) that lends a certain credibility to the prediction. When film is used in the same way, we know that it CAN last more than 20 years, but a lot of the old film hasn't stood up well. Pulling film more than twenty or thirty years old out of archives involves more of a restoration - now usually done digitally - than just a copying. The more important question is, when any stored information is pulled out of archive after 20 years or more, will we have a machine that can read it. There are (or were) tons of punch cards archived from the 40s and later that are essentially unreadable, because nobody makes pcard readers anymore. I'm sure there are large warehouses full of reel-to-reel digital tape, backups from the ancient dinosaur mainframes, that may (or may not - remember Schrödinger and his cat) have perfectly preserved data on them, but noone will ever try to read it because there are no machines left to do it on. As new storage media are developed, old ones drop into disuse, and the machinery to read them disappears. Does anyone remember the old 8 inch floppys that "modern" word processors used in the 80s. You could still buy them in 1990 - but can you find a drive now? Anybody tried to read the 5.25 inch floppies that were common in 1994 or so? Anyone tried to buy a NEW turntable that will play 78 rpms? A few years ago a well-known hard drive mfr advertised (on April Fool's Day) the startling new, incredibly fast "Write Only Drive" - with virtually unlimited capacity, and at very low cost. The few thousand people who contacted them for more information were probably disappointed, but frankly any idea that there is a way to put history away forever probably requires the use of the WOD. If history isn't alive enough to be occasionally dusted off and cleaned up, it might as well be filed on the Write Only ...(?) Long rant, but I feel better. I haven't checked whether the review is still up at the PCMagazine.com site, and I don't recall exactly when it was published, but some of their stuff is available at PCMag for anyone who might wish to look. John |
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29 Jul 01 - 02:30 AM (#516981) Subject: RE: How Well Do CDs last? From: wysiwyg John, that was fabulously written and well thought out. ~S~ |
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29 Jul 01 - 03:29 AM (#516986) Subject: RE: How Well Do CDs last? From: Peter Kasin Thank you, John. Ditto on WY's remarks. |
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29 Jul 01 - 04:02 AM (#516990) Subject: RE: How Well Do CDs last? From: SeanM I've got an AOL CD that's lasted as a good coaster for the last couple years... But seriously - I'll second or third the above. I'd say the advantage that CDs might have is the rate at which they insinuated into society in a couple of nitches - music, software, the similar technology of DVD, etc. Given that, and the fact that they're one of the only recording mediums currently that don't suffer degredation from use (beyond handling damage/scratches), I'd think they'll be something that will last a bit more in society. Could be wrong though. M |
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29 Jul 01 - 12:09 PM (#517164) Subject: RE: How Well Do CDs last? From: Peter T. It is vitally important that these modern archives deteriorate and die as soon as possible, so that future generations will not be burdened with the crap generated by our society. The prospect of having to reproduce and salvage the important things acts as a filter against littering time with trash. The Greeks and the Romans are still vital because 99% of what they wrote was lost, and only Plato and about 100 others survived. A shelf of Loeb classics covers most of it. Egyptian papyrus turns up from time to time, of mind bending dulness. yours, Peter T. |
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30 Jul 01 - 07:38 PM (#517990) Subject: RE: How Well Do CDs last? From: Burke A friend was telling me the other day that I could burn many, many audio tapes onto a single CD. From what you say, that too is not too smart, huh- audio tapes can be spliced. Magnetic media like tapes are probably less permanent than CD's and much easier to damage. Whatever you do refresh to the new technology before your capability to play to old one dies. |
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31 Jul 01 - 12:58 AM (#518174) Subject: RE: How Well Do CDs last? From: Dicho (Frank Staplin) Get with it! How are we to support our consumer society if products are made to last? Seriously though, unlike Peter T., some of us are interested in the old songs of over 100 years ago, and I have a nice collection of late Renaissance choral music. I keep my 78 turntable in good condition and always check piles of old records for jazz, blues and "folk." I am sure that many mudcatters do the same. I hope that I can preserve what I have, by transfer or whatever the archivists say should be done. |
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31 Jul 01 - 09:28 AM (#518317) Subject: RE: How Well Do CDs last? From: JohnInKansas There seem to be at least two questions being answered here, and the answers need to be different. The original question related to how an archive library should preserve historically significant information. The "creep-in" question is how we can preserve our personal music accumulations. The question of how to keep our personal stuff is probably the easiest. One approach is to get two copies of everything, and put one in good storage. An easy, and usually cheaper, alternative, for the fragile stuff like tape and records, is to immediately copy them to tape and "archive" the original. The critical thing is that with both tape and phono records, every time you "read" it, you probably make an ittybittyteenyweenyatomisticundetectable (yellow polka dot?) change to what's on the original, and the changes accumulate. Even in storage, though, phono records and tapes lose some of the data. I have a number of older 33s that have been in safe storage for about 20 years, and even on the best of turntables they don't sound as good as they did when they were new. (Some of the tapes I made then and used fairly often actually sound better now than the original disks.) Those who have the equipment to do so might want to put things onto a CD. Those who are really "gunh-ho" about it all might make one CD for storage and one to play from. For all practical purposes, relative to the life or interest span of the majority of us, this can be considered "permanent archiving." (Another advantage of that "master" CD that you put in storage is that you might be able to find it when the "emergency" comes up.) If you are going to do more than that for a personal collection, it is VERY important that you have named your executor and know that he/she is informed about the specific historical collection that will get your stuff (and your excellent index) when you're gone. For the historical archivist, the whole deal is a lot more complex. CD manufacture has been around for long enough to be a little better than black art for audio CDs. It may be expected that these will be playable for a fairly long time. For the "permanent historical" archiving of text and artwork, the situation is a little different. The first consideration is that the information has to be "made digital," and there are a number of different ways of doing that. At least one company, Information Handling Services (IHS) or something like that, has been leasing CD jukeboxes for about 15 years on which you can read almost any specification or standard known to man, if your company is willing to pay the lease fees. This makes it appear that there is an "established" standard for how to do it. The appearance of "utility burners" on PCs has clouded the situation somewhat. The CD writers used on PCs come in several forms, and there are at least a couple of standards in use. The situation gets a little more muddled when you talk ReWritable CDs, where 3 or 4 (if it's still Tuesday) competing standards seem to have about equal chance of surviving. If you go on to digital TV (DVD is only one of several) recordables and/or rewritables, you get into a maze of different standards and methods. The current crop of PC devices all attempt to address compatibility issues, but the best that can be said is that "some burners" using "some brands of blank disks" can make CDs that can be read or played by "some players." The only useful advice I've seen is "when you find something that works, stick with it." For the historical archivist, the thing to be feared is that one of these "systems" (the one with the richest backers, probably) should eventually emerge, and could obsolete what works now for them. SAVE OFTEN, AND PROTECT YOUR BACKUPS! The index for the Microsoft Windows 2000 Professional Resource Kit shows 59 entries under the general heading of "backup." This shows how very important this is! RESTORE YOUR FILES TO CURRENT MEDIA AT REGULAR INTERVALS! The index for the Microsoft Windows 2000 Professional Resource kit show ZERO entries related "restore." Maybe they'd like to forget some history? John |
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31 Jul 01 - 10:40 AM (#518354) Subject: RE: How Well Do CDs last? From: Gervase All storage media is vulnerable to data loss over time. Magnetic tape needs to be unwound and rewound "the other way round" (as it were) every so often to avoid "bleed" from one section of tape to another. The other problem with magnetic tape is that it's full of microscopic holes, so some data will not get written to the tape. As for CDs - just try hanging one up as a bird-scarer and see what happens in just a few weeks. They don't like UV light and changes in temperature or humidity. When in doubt, I'd say archive in a digital format, ideally on CD, and frequently update your archive to take account of the latest technology. Belt and braces is best. And never keep all your eggs in one basket - have at least one archive off-site because, as we all know, sh*t happens, and a fire or flood could wipe out the lot. |
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01 Aug 01 - 06:13 AM (#518906) Subject: RE: How Well Do CDs last? From: Grab I remember seeing something on New Scientist not too long back about a CD-eating bug (no this wasn't April 1st either!). Seems there's some little microbe that has a particular attraction for the metal layer in a CD, or for the glues that hold it there, or something. Graham. |
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18 May 03 - 08:18 PM (#955113) Subject: RE: How Well Do CDs last? From: JohnInKansas During a search for unrelated information, I came across a link to a back issue of RLG Diginews, apparently a periodical about a document/data preservation program ongoing at Cornell University – or at least one in which someone at Cornell participates. This issue is a "fifth anniversary recap" and is rather lengthy. It also dates to mid 2002, but it seems to have quite a lot of information that might be of interest to anyone concerved with archiving on a large scale. More appropriate for our librarians, perhaps, than those of us just saving songs. There have been a couple of other threads in the past year or two about archiving stuff, but this was the first one I pulled up. John |
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18 May 03 - 10:00 PM (#955157) Subject: RE: How Well Do CDs last? From: Blackcatter hi all I recently heard that the Library of Congress (or the Smithsonian - can't remember) Takes all the new CDs that are issued and records them onto laquer records. This is done because they know with care that the format will last for a long long time, and no matter what happens with technology, someone with a sewing needle 500 years from now will be able to listen to the music. |
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19 May 03 - 03:45 AM (#955245) Subject: RE: How Well Do CDs last? From: Mark Cohen What we need is Willis the Martian bouncer... (anybody remember him?) Aloha, Mark |
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19 May 03 - 04:16 AM (#955254) Subject: RE: How Well Do CDs last? From: Steve Parkes I started a thread on Sound archives decaying a while back, after seeing a piece in New Scientist. Mag tapes may become unusable. I'm archiving all my stuff on CDs. It will take me years (at the rate I'm going), but before the new medium becomes too badly degraded, I hope there'll be a newer and more reliable technology to transfer the archie on to. BTW, you can get turntables to play 78s, ranging from the basic to the fantastical: see that link above. Steve |
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19 May 03 - 04:21 AM (#955256) Subject: RE: How Well Do CDs last? From: GUEST,noddy typical we get persuaded to dump all our vinyl and buy CDs the greatest way of keeping music . Then we discover that 5 years down the line the CD is US. Lets go back to good old vinyl. |