D-I-Y CD data recovery via overspraying the lacquer layer?

[jkn]

Hi all I have an old data CD I want to recover the data from. Unfortunately it is a cheap CD and I'm getting loads of errors when trying to copy it. My experiments have included various SW CD recovery utilities etc.

The CD is one of those that, when you hold it up to the light, you can see through it slightly - always a bad sign in my book! My working assumption is that the raw S/Noise level from reading the pits is just too low.

As a desperate measure, I'm wondering about trying to improve matters by 'backing up' the lacquer layer, by overspraying it with something opaque. I realise that this is a risky approach; if I screw up the CD, well I'll just have to live with it.

Anyone heard of an approach like this working? Of course I'll have to be careful not to get spray on the other side of the CD. Suggestions as to what to use? Any better ideas? The data is of sentimental rather than monetary value.

Thanks for your thoughts

jon N

[Dave Plowman (News)]

I can't see how it will make any difference. The disc should be shielded from extraneous light while in the player. I'd try getting a friend to read it and copy it for you - players, even of the same make, tend to vary somewhat in what they will tolerate.

[jkn]

Hi Dave

Fair point about the extraneous light, and you may well be correct. I'm thinking more of trying to improve the reflection from the pits (cf the lacquer?? - must check up on this bit).

Forgot to mention that I've tried to read it in a number of readers already.

Jon

[Curious]

Data recovery software?

[Alex]

Have you tried using something like Linux instead of Windows to read it? It is often more forgiving of errors and will let you copy more data off.

Alex

[jkn]

Hi Alex

Yep, tried that (using dd etc.). I can't remember what error I got ... must have another look.

The data is old emails in MS .pst format, so unfortunately it probably needs complete files recovered to wor.

J

[Colin Wilson]

Has the bottom surface got any visible damage that might be causing problems ? - you can get them "skimmed and polished" for a couple of quid...

If the dye layer has deteriorated though, you might be knackered :-(

Have you tried any other drives ? - a newer drive might be more sensitive and able to retrieve the data.

[dennis]

Have you tried any writers? They tend to be better at reading than readers.

[Guy King]

The message from "dennis@home" contains these words:

As do DVD drives. They seem to be built to higher standards.

[kevallsop]

You might want to try this bit of freeware:

[Alan]

In message , jkn wrote

What about trying to manually reduce the read speed of the CD ROM drive? Slower reads may give better read results.

Your burning software may come with such a support utility or you may find something on the web.

[Aidan Karley]

Exactly the point I was indenting to make. "indenting" ?? "INTENDING" !! WTF is wrong with my typing this year?

[Weatherlawyer]

There was something in the tech news* several months ago about tape copy being a much safer format than home cut CD and DVDs**. The problem is that the dyes used decay or something like that.

You can get some scratched CDs to work by repolishing the bottom face with Brasso or something. That's if the scratches don't go through to the dye. But if the light is traveling through the CD, what would be the point of having it reflected back by a coat of paint that holds no info?

*Slash Dot or Inquirer or some-such. Try asking on Hermit's Cave, the Inquirer's forum. Don't mention overspraying or they will tear you apart. **As opposed to original factory cut disks which have information physically cut or molded into the disk. I trod on one such data disk and it split right through. It is still readable a few years later.

[Ian Stirling]

Well, not IME. Last time I checked my collection, I found no errors that were not there when the disks were authored. (I store checksums of all files on the disk, so checking is simply a matter of dropping them into the drive) These vary up to 10 years old.

Absolutely none of my floppies of that vintage will read without multiple errors.