4 ms·

I have CDs from the early 90s that still play fine. I have vinyl from the 70s that plays fine as well. I can resurface the CDs, not so much the vinyl.

TheSpiceIsLife 7y ago
If we’ve got data, let’s go with the data. If all we’ve got is opinions, let’s go with mine: None of the CDs I’ve ever bought still works. I’m probably not as careful with my things as you are, so there’s that.
- jonhohle 7y ago
  Your original comment was of your experience, so I shared mine. Unfortunately, due to manufacturing defects there are discs that will or have oxidized, so the durability of CDs (or other optical media) is not always as reliable as advertised. But as the sibling post to yours points out, CDs provide error correction and along with oversampling provides means of creating effectively bit perfect copies that can be as durable as the current state of the art (redundant, solid state, geographically diverse, etc.)
Godel_unicode 7y ago
You can also make an infinite number of perfect replicas of your CDs. You can carry backups of every CD ever made on a flashdrive that fits in your jeans pocket, then recreate any of them at any time with no degradation in quality. There are some quasi-plausible arguments for vinyl, but arguing that durability is one of them is hilariously myopic.
- deleted 7y ago
  [deleted]
- optimiz3 7y ago
  Sort of - sometimes there's sub-channel data that is very hard to properly replicate; only certain drives even expose that data to correctly extract. Making perfect audio CD image archives is surprisingly hard. E: Specifically I'm talking about the P & Q channels, but this can also include R through W which while technically unused, still contain data in some form.
  - paublyrne 7y ago
    What do you mean by "sub-channel"?
    - LegitShady 7y ago
      https://superuser.com/questions/1189222/cd-rom-subchannel-is-different-when-dumping-the-same-disc https://superuser.com/questions/1189222/cd-rom-subchannel-is... more information here
    - optimiz3 7y ago
      https://en.wikipedia.org/wiki/Compact_Disc_subcode https://en.wikipedia.org/wiki/Compact_Disc_subcode Most audio CD extractors do not provide all of this channel data, as only the digital audio is extracted. When a CD is re-burned, the subchannel data is regenerated, but not a bit-for-bit copy of the original. Sounds the same (usually), but sometimes there is metadata, easter-eggs, and what-not that is omitted. Additionally, some copy protection relied on adding corrupted subchannel data which low end CD players would skip, but high end extractors would not. Having the original subchannel data can be key and necessary to determine whether a sector was infact incorrectly extracted or not.
- tzs 7y ago
  > You can carry backups of every CD ever made on a flashdrive that fits in your jeans pocket Gracenote had 3 598 785 CDs in their database in 2005 [1], so I'll take that as a lower bound on the number of CDs ever made. I don't know what the largest flash drive that will fit in a jeans pocket is, but the largest I was able to find is 2 TB, but SanDisk showed a 4 TB prototype at CES 2019, so I'll go with that. Assuming lossless compression that averages reducing the size of a song by 75%, a 4 TB flash drive could hold 1 662 149.1 minutes of music. Unless the average CD is under 27.7 seconds long, that's not even enough to hold all the CDs known to Gracenote in 2005. Anyone want to do the math if we allow lossy compression to squeeze more in (although I wouldn't consider it a backup of the CDs if lossy)? [1] http://alchemi.co.uk/archives/mus/how_many_cds_ar.html http://alchemi.co.uk/archives/mus/how_many_cds_ar.html
  - jacquesm 7y ago
    Storage capacity has been increasing much faster than new CD volume is being created (relatively speaking), so if it isn't true today it soon will be.
  - andybak 7y ago
    Perceptually lossless and mathematically lossless are two different things. I'd be happy with the former.
    - Semaphor 7y ago
      But for a backup, you’d want actual lossless compression, wouldn’t you? Not for listening, but for re-encoding.
      - andybak 7y ago
        I think it's something I could tolerate sacrificing if the storage gains were substantial.
  - filleokus 7y ago
    If we move the goal post slightly, we could perhaps conceivably fit all 3.5 million CDs (compressed losslessly) on micro SD cards that would fit inside of the volume of a jewel CD case: https://www.wolframalpha.com/input/?i=177.5+cm%5E3%2F%28%28%283598785*700+MB*0.25%29%2F512+GB%29*165+mm%5E3%29 https://www.wolframalpha.com/input/?i=177.5+cm%5E3%2F%28%28%...
lightedman 7y ago
I have CDs from the 80s and 90s that are eaten by metal-eating bacteria. Good luck resurfacing that layer.
- r_c_a_d 7y ago
  Try contacting the original publisher. I did this with the small number of my discs that "rotted" and they were replaced with brand new ones without question. Probably because the industry made such a big deal about them "lasting forever" at the time of release. One disc was not replaceable (it was a weird compilation album that was no longer available) but the publisher let me pick another disc from their catalogue instead.

TheSpiceIsLife 7y ago

If we’ve got data, let’s go with the data. If all we’ve got is opinions, let’s go with mine: None of the CDs I’ve ever bought still works. I’m probably not as careful with my things as you are, so there’s that.

jonhohle 7y ago
Your original comment was of your experience, so I shared mine. Unfortunately, due to manufacturing defects there are discs that will or have oxidized, so the durability of CDs (or other optical media) is not always as reliable as advertised. But as the sibling post to yours points out, CDs provide error correction and along with oversampling provides means of creating effectively bit perfect copies that can be as durable as the current state of the art (redundant, solid state, geographically diverse, etc.)

Godel_unicode 7y ago

You can also make an infinite number of perfect replicas of your CDs. You can carry backups of every CD ever made on a flashdrive that fits in your jeans pocket, then recreate any of them at any time with no degradation in quality. There are some quasi-plausible arguments for vinyl, but arguing that durability is one of them is hilariously myopic.

deleted 7y ago
[deleted]
optimiz3 7y ago
Sort of - sometimes there's sub-channel data that is very hard to properly replicate; only certain drives even expose that data to correctly extract. Making perfect audio CD image archives is surprisingly hard. E: Specifically I'm talking about the P & Q channels, but this can also include R through W which while technically unused, still contain data in some form.
- paublyrne 7y ago
  What do you mean by "sub-channel"?
  - LegitShady 7y ago
    https://superuser.com/questions/1189222/cd-rom-subchannel-is-different-when-dumping-the-same-disc https://superuser.com/questions/1189222/cd-rom-subchannel-is... more information here
  - optimiz3 7y ago
    https://en.wikipedia.org/wiki/Compact_Disc_subcode https://en.wikipedia.org/wiki/Compact_Disc_subcode Most audio CD extractors do not provide all of this channel data, as only the digital audio is extracted. When a CD is re-burned, the subchannel data is regenerated, but not a bit-for-bit copy of the original. Sounds the same (usually), but sometimes there is metadata, easter-eggs, and what-not that is omitted. Additionally, some copy protection relied on adding corrupted subchannel data which low end CD players would skip, but high end extractors would not. Having the original subchannel data can be key and necessary to determine whether a sector was infact incorrectly extracted or not.
tzs 7y ago
> You can carry backups of every CD ever made on a flashdrive that fits in your jeans pocket Gracenote had 3 598 785 CDs in their database in 2005 [1], so I'll take that as a lower bound on the number of CDs ever made. I don't know what the largest flash drive that will fit in a jeans pocket is, but the largest I was able to find is 2 TB, but SanDisk showed a 4 TB prototype at CES 2019, so I'll go with that. Assuming lossless compression that averages reducing the size of a song by 75%, a 4 TB flash drive could hold 1 662 149.1 minutes of music. Unless the average CD is under 27.7 seconds long, that's not even enough to hold all the CDs known to Gracenote in 2005. Anyone want to do the math if we allow lossy compression to squeeze more in (although I wouldn't consider it a backup of the CDs if lossy)? [1] http://alchemi.co.uk/archives/mus/how_many_cds_ar.html http://alchemi.co.uk/archives/mus/how_many_cds_ar.html
- jacquesm 7y ago
  Storage capacity has been increasing much faster than new CD volume is being created (relatively speaking), so if it isn't true today it soon will be.
- andybak 7y ago
  Perceptually lossless and mathematically lossless are two different things. I'd be happy with the former.
  - Semaphor 7y ago
    But for a backup, you’d want actual lossless compression, wouldn’t you? Not for listening, but for re-encoding.
    - andybak 7y ago
      I think it's something I could tolerate sacrificing if the storage gains were substantial.
- filleokus 7y ago
  If we move the goal post slightly, we could perhaps conceivably fit all 3.5 million CDs (compressed losslessly) on micro SD cards that would fit inside of the volume of a jewel CD case: https://www.wolframalpha.com/input/?i=177.5+cm%5E3%2F%28%28%283598785*700+MB*0.25%29%2F512+GB%29*165+mm%5E3%29 https://www.wolframalpha.com/input/?i=177.5+cm%5E3%2F%28%28%...

lightedman 7y ago

I have CDs from the 80s and 90s that are eaten by metal-eating bacteria. Good luck resurfacing that layer.

r_c_a_d 7y ago
Try contacting the original publisher. I did this with the small number of my discs that "rotted" and they were replaced with brand new ones without question. Probably because the industry made such a big deal about them "lasting forever" at the time of release. One disc was not replaceable (it was a weird compilation album that was no longer available) but the publisher let me pick another disc from their catalogue instead.