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sxz



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Topic # 32145 14-Apr-2009 15:51
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in 2003 I had a holiday in England and transfered 256mb of photos to a CD.

I stood on the CD before I got home to back up the photos.

I just found the CD, crack and all, and was wondering if there was a program or advice in general that would ignore the read errors created by the crack in the cd and pull whatever data it could? Just thought it would be pretty sweet if I even could get 10 - 20 of the 200 some photos back again....

Its a clean break through the entire cd from one edge to the centre.

cheeers

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  Reply # 207200 16-Apr-2009 05:35
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One issue will be the forces at work on a CD when it is spinning. At the speed it spins at that crack will be opening up considerably, probably blowing the disk apart.

That is before the drive even gets a chance to try and read a broken data stream.

But I don't know for sure, so I will never say never.

I assume it is a DIY type solution you are looking for, rather than a "pay a data recovery company a couple of grand" type solution?

sxz



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  Reply # 207417 16-Apr-2009 23:51
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True that, and yeah - tape solution.

I just figured - and I know my example is crude - that the crack represents prehaps 2 degrees of the entire cd which equates to roughly .6% of the data...

So I thought - theoretically, taping up the back of the cd (as smoothly as possible) and retrieving whatever data I can...

I'm sure it is theoretically possible, or forensically possible, and I'm sure I wont get a solution. but I thought maybe there was a small shot at a macgiver recovery...

 
 
 
 


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  Reply # 207426 17-Apr-2009 00:08
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sxz: True that, and yeah - tape solution.

I just figured - and I know my example is crude - that the crack represents prehaps 2 degrees of the entire cd which equates to roughly .6% of the data


If you cut a slice out of the middle of your garden hose .6% of the length of your garden hose wide, does water still make it out the other end?

Another crude example but just remember, the data on a CD is scattered around everywhere, it is not like cutting a slice out of a cake and still being able to eat the rest of what is left :-)

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  Reply # 207454 17-Apr-2009 07:28
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I'd say that it'd be pretty hopeless. A really smooth tape job may get the CD back together, but i'd try and balance the tape (an out of balance CD will blow a CD drive apart as quick as a broken one). See if you can get hold of a really old CD rom (a good old Creative QuadSpeed) so it doesn't try and spin it up too fast - and if it does blow to pieces won't wreck your nice new fast one.

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  Reply # 207474 17-Apr-2009 09:08
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Why would the data be scattered around? A CD isn't like a hard drive where data gets written to previously used spaces, the data would be burnt sequentially from the center out.

trig42 has a good point to look for a slow drive, you can limit drive speed but some drives will still spin up to full speed 1st.

mjb

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  Reply # 207478 17-Apr-2009 09:21
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The problem will be that part of the session data will be lost from the crack, and will likely make the entire disk unreadable.




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  Reply # 207501 17-Apr-2009 09:56
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Isobuster might help or even one of the photo recovery programs.

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  Reply # 207503 17-Apr-2009 09:58
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If you have a tray loading drive how about gluing the damaged CD  to a CD-R or a thin piece of Plastic to hold them in play together.

But as mentioned the crack goes all the way through to the middle, so it will ruin the Table of Contents,

But you might want to look at some of the recovery software that it out there to see if you can lift the raw data from the disk



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  Reply # 207550 17-Apr-2009 12:22
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Data is written lineraly in a spiral pattern from the very inside towards the outside, if you had only damaged only a one region of the disk you might have been alright, but given that the disc is damaged all the way through, it is very unlikely you will recover any data

As others have said, the discs do spin very fast and are likely to shatter... so be warned.




pɐǝɥ sıɥ uo ƃuıpuɐʇs

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  Reply # 207552 17-Apr-2009 12:31
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In the interest of science etc I tried to recreate this but couldn't get my cd to crack before it just distorted badly like a taco.

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  Reply # 207554 17-Apr-2009 12:33
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Bung: In the interest of science etc I tried to recreate this but couldn't get my cd to crack before it just distorted badly like a taco.


Ha ha yeah I've noticed that before, some discs shatter/crack, others just bend.

And I apologise for the scatter comment above, I clearly wasn't thinking :-) Filterer just beat me to the bit about the "track" being sliced in many places from start to finish.

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  Reply # 207765 18-Apr-2009 13:21
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1) Download Nero Drive Speed and reduce the speed of your drive to 1X or whatever is the lowest possible.

2) You can tape the back of the CD if you can; at 1X speed it shouldn't make a big difference.

3) There's a good chance of getting back your data, but expect quite a few files to be corrupted. Use IsoBuster for recovery and when it comes across an unreadble sector, ask it to use dummy data (fill with 0s) and apply it to all future errors.

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  Reply # 207767 18-Apr-2009 13:36
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CD's are designed so that little scatches don't cause the whole disk to be faulty, there is some degree of redundancy.  First, don't throw the disk away.  I suspect that the data is easy to get off using a digital microscope, accurate x-y table and a lot of computer processing.  I'm sure that the NSA has got a working system.  Of course for OP, it's unlikely they'll want to go to the bother of finding this solution.  For those who have lost data (I think we all have, at one time or another) the best rule of backing up is 3 copies in two physical locations.

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  Reply # 207774 18-Apr-2009 13:58
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-request services of an unsuspecting friend
-wear disguise
-meet in a dimly lit car-park somewhere
-make sure there are some CCTV cameras
-exchange CD in a brown paper bag for a bigger brown paper bag
-once you have been held for questioning, the CSI team will extract your data

Cool




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sxz



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  Reply # 207950 19-Apr-2009 16:40
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coffeebaron: -request services of an unsuspecting friend
-wear disguise
-meet in a dimly lit car-park somewhere
-make sure there are some CCTV cameras
-exchange CD in a brown paper bag for a bigger brown paper bag
-once you have been held for questioning, the CSI team will extract your data

Cool



Fantastic - I totally love this idea!!

Yeah I have worried about putting it in my new laptop, incase it comes apart or screws the drive - might have to try that ISO buster idea, thats the sort of thing I was after with the filling of gaps with blank data and corrupting some of the files while hopefully pulling out one or two readable photos. I'm gonna try dig up an old crusty laptop and give it a go

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