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Flood göndermek, insanların floodlarını okumak ve diğer insanlarla bağlantı kurmak için sosyal Floodlar ve Flood Yanıtları Motorumuza giriş yapın.

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Multiple questions regarding CD reading and unreadable CDs

If this subreddit is not the best discussion for this please point me to the right place even if its outside of reddit.

I have many CDs (~20) that are in good physical condition but some are unreadable while others are readable with problems. They have been cleaned with cloth and been tried in 2 different CD/DVD roms. There are minimal scratches with no affect on actual readability.

Problem: Some disks read fine but aren’t able to copy properly. They have a few “bad sectors” but the content is 90%+ fine. In File Explorer while browsing the disk, I am able to see pictures clearly with no artifacts. Copying from the disk directly or using a program to force copy will result in extremely slow copy speeds when it hits a “bad sector” taking several minutes to copy a 3-5MB file. Opening the file after the copy completes will show many artifacts on the image or most of the time the image is too corrupt it doesn’t even preview, while it shows fine in preview on the CD (not opening the file, just shows the picture on icons). Suggestions? Anybody knows why the image preview is fine on the icons but doesn’t show properly after?

Problem 2: Half of my CDs don’t read at all. They have been left close to a window with sunlight for a while. Could that be the cause of the unreadability? Some CD/DVD roms use different colored lasers, could that change the outcome? While hard to tell, it’s still possible to see the burned portion with data on the disk. Suggestions?

**Conclusion** 15 hours of time or so wasted on this crap. I used ISOBuster but didn’t bother with complicated recovery techniques. I just made the program copy everything possible and skip when it comes to damaged sector. Got about 60% of all data completely recovered, 2 disks are still completely unreadable, and was able to get about 70-80% data from 3 other disks, and one disk is only 25% fine. Tried ddrescue but it did the same thing but it’s much more complicated to use and takes much longer.

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  1. Dye degrades over time. I would recommend ISOBUSTER to attempt to recover any media from them.

  2. >Half of my CDs don’t read at all. They have been left close to a window with sunlight for a while. Could that be the cause of the unreadability?

    The UV radiation from sunlight will break down the DNA in your skin tissue. …How do you think your optical media will fare? 😛

  3. Try to read them with RoadKil’s Unstoppable Copier. I was able to dump some really bad disc using this.

  4. Sounds like they have copy protection… or you need a totally different brand/type drive.
    Sometimes the lasers have issues with certain cd reflective surfaces/dye sets.

    Try isobuster.

  5. A few notes from my own experiences:

    There is no best drive. Sometimes drive A can read a damaged disc better than drive B, and sometimes it’s the other way around. Different drives seem to be able to better manage different types of disc issues, with no one always being best.

    It’s very possible that you’ll need to use a mix of drives to extract all data possible. The isobuster software can help with this. It has an option to try to reread all damaged sectors, and you can move the disc among different drives and have the software try to reread the damaged sectors in each drive.

    As for the previews working for images, there are a few possible explanations. It’s possible there’s a database of thumbnails stored in a different (readable) location on the disc. Another possible explanation is that some image files store a thumbnail inside the image file (so there’s actually like a second, tiny image inside the main image), and the thumbnail may be on a readable part of the disc while the main image isn’t.

    If the data is important enough to spend some money on, I’d probably try to score a small lot of used optical drives (of various models) on eBay, along with a USB to SATA adapter to hook them up externally. Then I’d try every disc in every drive to try to extract as much data as possible. Basically, hook up a drive, try all the disks, hook up another drive, try the discs again, …

    Some people may recommend an old, expensive Plextor drive (along with a PATA to USB adapter — SATA versions of “real” Plextor drives are stupid expensive). I dunno how they do at reading CDs that were left in the window, but they’re absolute dog shit at reading damaged data CDs in general in my experience (though are probably better at audio, so it might be worth considering if any of those discs are audio CDs).

  6. Maybe try an error-resilient copier:

    [https://alternativeto.net/software/roadkils-unstoppable-copier/about/](https://alternativeto.net/software/roadkils-unstoppable-copier/about/)

    And/or try to limit the reading speed:

    [https://alternativeto.net/software/cdslow/](https://alternativeto.net/software/cdslow/)

    Try more drives for reading. Some are better.

    If plain reading works, copying would work just as well (unless the drive you write to is the problem). The thumbnails looking fine could be JPEG files with an embedded thumbnail. If so, it’s not generated from the full-size image.

  7. Take a look at ddrescue. It’s made specifically to clone failing media: it’ll first clone the healthy parts, and then you can do as many clone passes as you want to fill the rest, until you have a good clone (or at least as good as you can).

    Here is a guide for CDs/DVDs: https://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html#Optical-media

  8. Writable CDs are notorious for their short shelf life, and that gets even shorter with light exposure. You might have better results in a different model of drive though – I’ve found that approach worked for me in the past. Some drives seem better able to read the degraded discs than others.

  9. Examine the disks. Are they scratched? Is the reflective coating peeling off? What DVD Drive(s) have you tried. Plextor and Pioneer are best for reading damaged disks. If the disk is scratched, it is well worth having them cleaned professionally. Unfortunately with the demise of optical media, finding a DVD Rental with a proper Disc cleaning machine is rare.

  10. The typical CD-R(W) / CD+R(W) has a shelf life of 5-10 years unfortunately. The lifespan depends heavily on how they were manufactured and some brands do last longer but outside of very high quality discs and archival discs 10 years is generous.