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CD Roms Longevity
Hi,
From time to time, I come across an article about CD roms, etc. What I have learned so far, CD-R (I use) is better than CD-RW for long term storage of important data. Also, how they are stored can have a bearing on their "life". I keep CD roms in a dark cool location. To test the integrity of my "burned" CD roms, I use "Finder" (search engine) I downloaded from www.simtel.net. I "search" for a non-existant text pattern such as "i don't exist" in order to get "Finder" to read through every file on the CD rom as a way to check for corrupt data. Note: "Finder" has reported read errors on some of my floppy disks. So far, no read errors were reported. However, I started burning CD roms about 4 years ago. Is the integrity of commercial CD roms better than those I "burn" at home? How long can we expect to keep our CD roms, assuming they are stored in a good environment, before we begin to encounter corrupt data? Thanks in advance, Brad Before you type your password, credit card number, etc., be sure there is no active key logger (spyware) in your PC. |
CD Roms Longevity
"Brad" wrote in message ... Hi, From time to time, I come across an article about CD roms, etc. What I have learned so far, CD-R (I use) is better than CD-RW for long term storage of important data. Also, how they are stored can have a bearing on their "life". I keep CD roms in a dark cool location. To test the integrity of my "burned" CD roms, I use "Finder" (search engine) I downloaded from www.simtel.net. I "search" for a non-existant text pattern such as "i don't exist" in order to get "Finder" to read through every file on the CD rom as a way to check for corrupt data. Note: "Finder" has reported read errors on some of my floppy disks. So far, no read errors were reported. However, I started burning CD roms about 4 years ago. Is the integrity of commercial CD roms better than those I "burn" at home? How long can we expect to keep our CD roms, assuming they are stored in a good environment, before we begin to encounter corrupt data? The simple answer to that seems to be 'no-one knows for certain'. I've read 10 and 25 years, but I take such claims with a pinch of salt. Just look at laser discs, some of them were inherently faulty and developed 'sparkles' as they deteriorated over the years. Unfortunately, it seems no data storage medium is even close to perfect. Dave |
CD Roms Longevity
"Brad" wrote in message ... Hi, From time to time, I come across an article about CD roms, etc. What I have learned so far, CD-R (I use) is better than CD-RW for long term storage of important data. Also, how they are stored can have a bearing on their "life". I keep CD roms in a dark cool location. To test the integrity of my "burned" CD roms, I use "Finder" (search engine) I downloaded from www.simtel.net. I "search" for a non-existant text pattern such as "i don't exist" in order to get "Finder" to read through every file on the CD rom as a way to check for corrupt data. Note: "Finder" has reported read errors on some of my floppy disks. So far, no read errors were reported. However, I started burning CD roms about 4 years ago. Is the integrity of commercial CD roms better than those I "burn" at home? Apples to oranges. Factory discs are not burned, they are pressed (i.e., molded) in the desired pattern. Writeable discs use dyes which are fixed by the laser light to store the pattern. Hence, pressed CD's don't generally degrade from subsequent exposure to the wrong kinds of light as do burned discs. Extending the topic a little to DVD's, there is an unfortunate phenomenon known as "rotting" which occurs even on factory discs. This happens when defective bonding leads to layer separation. How long can we expect to keep our CD roms, assuming they are stored in a good environment, before we begin to encounter corrupt data? It varies. Assuming identical storage solutions, the main difference is in brands used. But even that's hotly debated. You'll find users of the cheapest crap on the planet proudly proclaiming their discs have lasted 5+ years, while others wouldn't touch them with a ten foot pole. Brand loyalty comes into play as well. If you loved your old verbatim floppies, you might want to stick with verbatim CD's, etc. I personally buy name brand cakeboxes that offer the best value at that time. Usually, they end up being TDK and Maxell, both of which have produced very good magnetic media over the years and I have no prob trusting either company's CD's. As a general rule of thumb with optical media, you should back up the most precious data at least once a year. That includes DVD's. Data you can afford to lose might get backed up once every few years. There's enough evidence to clearly indicate the hype when writeable optical discs first came out was utterly bogus. Your recording will last a hundred years!!?? Pretty funny. |
CD Roms Longevity
"Dave D" writes:
"Brad" wrote in message ... Hi, From time to time, I come across an article about CD roms, etc. What I have learned so far, CD-R (I use) is better than CD-RW for long term storage of important data. Also, how they are stored can have a bearing on their "life". I keep CD roms in a dark cool location. To test the integrity of my "burned" CD roms, I use "Finder" (search engine) I downloaded from www.simtel.net. I "search" for a non-existant text pattern such as "i don't exist" in order to get "Finder" to read through every file on the CD rom as a way to check for corrupt data. Note: "Finder" has reported read errors on some of my floppy disks. So far, no read errors were reported. However, I started burning CD roms about 4 years ago. Is the integrity of commercial CD roms better than those I "burn" at home? How long can we expect to keep our CD roms, assuming they are stored in a good environment, before we begin to encounter corrupt data? The simple answer to that seems to be 'no-one knows for certain'. I've read 10 and 25 years, but I take such claims with a pinch of salt. Just look at laser discs, some of them were inherently faulty and developed 'sparkles' as they deteriorated over the years. Unfortunately, it seems no data storage medium is even close to perfect. This is certainly true. I think the cool storage is fine but it should also be dry. Dark probably doesn't matter that much as long as there isn't much UV. --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. |
CD Roms Longevity
Sam Goldwasser wrote:
"Dave D" writes: "Brad" wrote in message ... Hi, From time to time, I come across an article about CD roms, etc. What I have learned so far, CD-R (I use) is better than CD-RW for long term storage of important data. Also, how they are stored can have a bearing on their "life". I keep CD roms in a dark cool location. To test the integrity of my "burned" CD roms, I use "Finder" (search engine) I downloaded from www.simtel.net. I "search" for a non-existant text pattern such as "i don't exist" in order to get "Finder" to read through every file on the CD rom as a way to check for corrupt data. Note: "Finder" has reported read errors on some of my floppy disks. So far, no read errors were reported. However, I started burning CD roms about 4 years ago. Is the integrity of commercial CD roms better than those I "burn" at home? How long can we expect to keep our CD roms, assuming they are stored in a good environment, before we begin to encounter corrupt data? The simple answer to that seems to be 'no-one knows for certain'. I've read 10 and 25 years, but I take such claims with a pinch of salt. Just look at laser discs, some of them were inherently faulty and developed 'sparkles' as they deteriorated over the years. Unfortunately, it seems no data storage medium is even close to perfect. This is certainly true. I think the cool storage is fine but it should also be dry. Dark probably doesn't matter that much as long as there isn't much UV. --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. One thing i learned recently about optical disks disturbed me. I had always taken the most care to protect the data side of the disk. I found out that the most fragile side is actually the one with the label. It's the one closest to the actual media. A scratch there--one which might not even glitch a reader if it were on the other side--can expose the metallic layer to corrosion. jak |
CD Roms Longevity
jakdedert writes:
One thing i learned recently about optical disks disturbed me. I had always taken the most care to protect the data side of the disk. I found out that the most fragile side is actually the one with the label. It's the one closest to the actual media. A scratch there--one which might not even glitch a reader if it were on the other side--can expose the metallic layer to corrosion. Yeah, and a piece of sticky tape may pull it off entirely on CD-R/RWs! :( --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. |
CD Roms Longevity
On 2006-03-18, Sam Goldwasser wrote:
jakdedert writes: One thing i learned recently about optical disks disturbed me. I had always taken the most care to protect the data side of the disk. I found out that the most fragile side is actually the one with the label. It's the one closest to the actual media. A scratch there--one which might not even glitch a reader if it were on the other side--can expose the metallic layer to corrosion. Yeah, and a piece of sticky tape may pull it off entirely on CD-R/RWs! :( That's why I've never used CD-labels. I used to label my CDs directly with permanent OHP pens, but now I use specialized CD pens. (I think the price is about the same these days.) |
CD Roms Longevity
On 17 Mar 2006 22:31:21 -0500, Sam Goldwasser wrote:
jakdedert writes: One thing i learned recently about optical disks disturbed me. I had always taken the most care to protect the data side of the disk. I found out that the most fragile side is actually the one with the label. It's the one closest to the actual media. A scratch there--one which might not even glitch a reader if it were on the other side--can expose the metallic layer to corrosion. Yeah, and a piece of sticky tape may pull it off entirely on CD-R/RWs! :( Hmmm, that sounds like the voice of experience! -- Australia isn't "down under", it's "off to one side"! www.cobracat.com (home of the Australian Cobra Catamaran) http://groups.yahoo.com/group/cobra-cat/ |
CD Roms Longevity
Adam -
I would think that a CD label would be a GOOD thing, as long as you don't pull it off (and why would you?). It would be a barrier against the inadvertent scratches that happen during handling. Yes? No? It would also tend to keep ambient light out of the disk - or at least the side that is normally stored upward, facing the light. Bill ============================= Adam Funk wrote: That's why I've never used CD-labels. I used to label my CDs directly with permanent OHP pens, but now I use specialized CD pens. (I think the price is about the same these days.) |
CD Roms Longevity
Sam Goldwasser wrote:
This is certainly true. I think the cool storage is fine but it should also be dry. Sam - Some of us don't have the advantage of a dry climate. Here in Arizona things are usually quite dry, for example. But I have half of my DVDs stored on the coast in Maine, where it is quite humid at least 9 months of the year. I assume it would be helpful to put my DVDs in some sort of waterproof box - even a big Tupperware box - and toss in a couple of the "Do Not Eat" silica gel packets that come in bags of rice crackers and other crispy foods? Bill |
CD Roms Longevity
"Bill Jeffrey" wrote in message news:2CWSf.9131$z82.8920@fed1read07... Adam - I would think that a CD label would be a GOOD thing, as long as you don't pull it off (and why would you?). It would be a barrier against the inadvertent scratches that happen during handling. Yes? No? It would also tend to keep ambient light out of the disk - or at least the side that is normally stored upward, facing the light. The adhesive on labels contains solvents which may compromise the CD's coating over time, or even break it down altogether. I personally would never attach anything sticky to my CDs or DVDs, least of all my most precious and irreplaceable ones. Dave |
CD Roms Longevity
On 2006-03-18, Bill Jeffrey wrote:
Adam - I would think that a CD label would be a GOOD thing, as long as you don't pull it off (and why would you?). It would be a barrier against the inadvertent scratches that happen during handling. Yes? No? It would also tend to keep ambient light out of the disk - or at least the side that is normally stored upward, facing the light. I've been under the impression that the adhesives damage the coating. (I could be wrong.) |
CD Roms Longevity
Adam Funk writes:
On 2006-03-18, Bill Jeffrey wrote: Adam - I would think that a CD label would be a GOOD thing, as long as you don't pull it off (and why would you?). It would be a barrier against the inadvertent scratches that happen during handling. Yes? No? It would also tend to keep ambient light out of the disk - or at least the side that is normally stored upward, facing the light. I've been under the impression that the adhesives damage the coating. (I could be wrong.) It's possible. Some solvents will make the coating literally peel off on its own. --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. |
CD Roms Longevity
"Adam Funk" wrote in message ... On 2006-03-18, Bill Jeffrey wrote: Adam - I would think that a CD label would be a GOOD thing, as long as you don't pull it off (and why would you?). It would be a barrier against the inadvertent scratches that happen during handling. Yes? No? It would also tend to keep ambient light out of the disk - or at least the side that is normally stored upward, facing the light. I've been under the impression that the adhesives damage the coating. (I could be wrong.) Labels aren't permanent and can cause a variety of problems; among the ones I've seen are causing jamming in slot-loading machines, and clamping problems in regular tray or carousel models. On a regular machine, if any adhesive migrates a bit, the disc can stick to the clamper and also cause jamming problems. Mark Z. |
CD Roms Longevity
Dave D wrote:
"Bill Jeffrey" wrote in message news:2CWSf.9131$z82.8920@fed1read07... Adam - I would think that a CD label would be a GOOD thing, as long as you don't pull it off (and why would you?). It would be a barrier against the inadvertent scratches that happen during handling. Yes? No? It would also tend to keep ambient light out of the disk - or at least the side that is normally stored upward, facing the light. The adhesive on labels contains solvents which may compromise the CD's coating over time, or even break it down altogether. I personally would never attach anything sticky to my CDs or DVDs, least of all my most precious and irreplaceable ones. Dave Thanks, Dave. Didn't know that. Bill |
CD Roms Longevity
On 2006-03-18, Dave D wrote:
The adhesive on labels contains solvents which may compromise the CD's coating over time, or even break it down altogether. I personally would never attach anything sticky to my CDs or DVDs, least of all my most precious and irreplaceable ones. Thanks. I'll keep using the CD pens. |
CD Roms Longevity
In article 2CWSf.9131$z82.8920@fed1read07,
Bill Jeffrey wrote: I would think that a CD label would be a GOOD thing, as long as you don't pull it off (and why would you?). *You* may not pull it off, however, your 68x SoopaDVDCombo drive may well do that, in passing. The resulting mess will not be pretty. I've had labels start to peel at the edges. The discs were clean, the labels not "handled" at the edge. The discs were well stored. Fortunately, the disks had a rhino hide coating on them that allowed the label to be soaked off. I've stopped using labels since. I just don't trust them to stick properly! To the poster talking of "Finder", running a program to read all the data is one way of knowing that it's TOO LATE for some of your data. However, you can get an early warning of impending failure by using a PROPER utility like Nero CD-Speed. This will run over the disk and show you a count of C1 and C2 errors. On most disks you get a handful of C1 errors (low level) over the disk. And maybe a C2 error or two. These aren't a problem. If you scan a disk and get hundreds of C1 errors, or handfuls of C2 errors, then your disk is on the way out. Copy it ASAP. You get a feel for what is "normal" after running CDROMS, CD-Rs etc. through the drive. A really bad "C-GRADE NONAME CDR" will look like the side of a mountain, as the C1 error count starts off and ramps into the THOUSANDS. This scan is done BEFORE you get to the state of data corruption where the OS is sitting there saying "File error". Error correction is a wonderful thing, but could be hiding the fact that your data is g=tting v ry fl ky ind%!d. Mike. -- --------------------------------------+------------------------------------ Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/ |
CD Roms Longevity
In article ,
Stan Blazejewski wrote: Yeah, and a piece of sticky tape may pull it off entirely on CD-R/RWs! :( Hmmm, that sounds like the voice of experience! I've seen a set of CDs "helpfully" labelled with 3-M PostIts[tm] to aid identification: "This CD Works" "This didn't boot" etc. After removal of the PostIt, most of them could be labelled with "This Is Now Scrap" "Another Coaster" "Look At The Cool Blue Window In This CD" as it pulled the metallisation right off. This is not normal for CD-Rs, however, somebody forgot to lacquer coat the shiny side of the disks, and that would be why they were so cheap. Penny pinching purchasing department strikes again. -- --------------------------------------+------------------------------------ Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/ |
CD Roms Longevity
Apples to oranges. Factory discs are not burned, they are pressed (i.e., molded) in the desired pattern. Writeable discs use dyes which are fixed by the laser light to store the pattern. Hence, pressed CD's don't generally degrade from subsequent exposure to the wrong kinds of light as do burned discs. Extending the topic a little to DVD's, there is an unfortunate phenomenon known as "rotting" which occurs even on factory discs. This happens when defective bonding leads to layer separation. Some of the separation can be attributed to exposure to temperature variations. As each material (metal, plastic a, plastic b-coating, etc.) expands and contracts at differing rates, separation at mostly the edges where stresses are greatest begins to show up as a "feathering discolorization" Don't store cds or dvds near heat or near cold sources as this will reduce life of the data. Constant, cool temperatures are the rule. Cheers, Hank |
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