Cyclic redundancy check???

[Raiden1803]

alright what the hell, disc bad? i burned this a day ago and tried to extract a file...

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[RZetlin]

Yes, the burning on the disc is bad. Even if the burning of the disc is successful there's still the chance of bad burns.

Did you use Nero?

You didn't verify the disc did you?

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[Gamer1]

yea that's what happens when disks gets too old or bad disks, or the data is corrupt.

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[KillerShots]

This means the built-in error checking noted a bad block of data. Discs follow this for data: 32 bits of data, 32 bits of CRC that the data MUST fit to be valid. Without this, you'd never know that the data was bad. Due to the nature of CRC, if you have low-level access, you can attempt to reproduce what the CRC thinks the value should be... but the CRC is probably also incorrect, so you've got 2^32 possible values of that 32-bit chunk of data. Unless this data is truly critical (if so, you've got other backups, right?), I'd consider it a loss and move on.

Something I'd always considered doing was writing a program that could give me "double capacity" on CDs by eliminating CRC... but (1) I don't know if I can eliminate this with software (hardware could be hard-wired to do it) and (2) It would NOT be a good idea because you'd never know if your data's good or not.

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[Snake785]

You could seriously get close to about double capacity if you take out the CRC? Now that'd be nice.

Anyways Raiden, what speed did you burn this disc at? Try burning it at a lower speed and make sure nothing else is running in the background (those programs can cause the burning program to choke for a split second, causing errors in the data it's burning. Not likely if you have burn-proof or whatever but still very possible).

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[Badaro]

Originally Posted by Snake785

You could seriously get close to about double capacity if you take out the CRC? Now that'd be nice.

IIRC a data CD-ROM has around 250-300 bytes of error-correction for each 2048 bytes of data... so stripping the error-correction would increase the capacity by about 15%.

[]s Badaro

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[Raiden1803]

Originally Posted by RZetlin

Yes, the burning on the disc is bad. Even if the burning of the disc is successful there's still the chance of bad burns.

Did you use Nero?

You didn't verify the disc did you?

Yes I used Nero, And it made me Verify The disc (Finalaizng?) Because my disc is 700MB and that file was around the same.


EDIT

Originally Posted by Snake 785

Anyways Raiden, what speed did you burn this disc at?

8x speed

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[RZetlin]

Originally Posted by Raiden1803

Yes I used Nero, And it made me Verify The disc (Finalaizng?) Because my disc is 700MB and that file was around the same.
EDIT
8x speed

Ack, finalizing the disc is not the same as disc verification.

Finalizing the disc is closing the disc for no more writing.

When you start burning the disc, there's an option right at the bottom that says, "Verify written data". That has to be checked off.

You can also verify the disc using Nero CD-DVD program (Extra->ScanDisc).

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[Kane]

Finalising <> Verifying disc. The verify option appears while you are actualy burning, as a check box next to 'shut down PC when done'.
Finalising the disc is nothing to do with checking disc integrity, it's for preventing anymore data being written to a multi-session disc. Finalising is forced on when you are doing a disc with 'no multisession', or if you burn 'Disc at Once '96'

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[Raiden1803]

the problem is that files no longer on the hd, i did a full format. which is why i put the file on the disc in the first place, but i burned 4 orther discs the same way and that one is the only one that gives me Cyclic Redundancy Check. if i clone the cd would i get the same thing?

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[Razor Blade]

You could always try. It would b e better if you tested on a CD-RW so you don't waste any CD-R's (not that they're expensive)

Yea, that happened to me once - Had a bad burn and lost some files. Jst take this as a lesson to test your burnt CD's before formatting or deleting the data.

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[RZetlin]

Originally Posted by Raiden1803

the problem is that files no longer on the hd, i did a full format. which is why i put the file on the disc in the first place, but i burned 4 orther discs the same way and that one is the only one that gives me Cyclic Redundancy Check. if i clone the cd would i get the same thing?

Then you're out of luck. You have to download the files again from the internet.

If you clone the CD you're going to be reading a bad sector on the flawed disc -- making the disc unreadable for that particular area.

That's why I always run Nero ScanDisc on every CDs I burn and copy the data on the burned CD back to the hard drive to make sure everything is okay.

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[james.miller]

that doesnt always mean the burn is bad. Ive got an NEC2500a and they are well known for their reading problems. Slightest bit of dirt on a cd and it will chuck a CRC error at me. In my case, and many other people with 2500a's, it's nothing to do with a bad burn.

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[Kirby]

mostly this error happens on floppy disks, but sometimes it can happen on a CD. All this is telling you is that the sector is damaged, and you'll either need to "quarentine" the bad sectors using a proggy called DiskChecker (only for floppies), or throw away the disk

and IRC people....don't play dumb with me. I have these errors with my disks frequently

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Last edited by Kirby; July 22nd, 2004 at 19:59..

[Demigod]

If the disc is damaged then you can probably try repairing it. Of course if you burned the CD while it was damaged then there's virtually no hope of recovery, even if you restored the CD. I would also heed james.miller's advice and try the CD in another drive. I had a 8x DVD-ROM drive that would constantly choke on CDs and make a number of read errors, even when there was nothing wrong with the disc. From your description though I think it's most likely that the disc is bad.

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[Raiden1803]

how do you repair it?

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[D.D.]

if using something like "Gamedoctor" or "DVD doctor" (something like that which u can pick up at walmart or business depot) doesnt work, use a program called CDcheck. it'll read the file several times and salvage wut it can. u'll end up with errors, but at least some of it is retrieved. I use it a lot for anime.

http://elpros.si/CDCheck/

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[KillerShots]

Yeah, disc doctor products work well for scratched media... they actually sand off layer after layer until the scratch goes away (you end up with a slightly thinner disc). I've saved a couple of hopeless discs with that.

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[RZetlin]

Originally Posted by D.D.

if using something like "Gamedoctor" or "DVD doctor" (something like that which u can pick up at walmart or business depot) doesnt work, use a program called CDcheck. it'll read the file several times and salvage wut it can. u'll end up with errors, but at least some of it is retrieved. I use it a lot for anime.

http://elpros.si/CDCheck/

Gamedoctor only works with physically damaged CDs that are scratched on the bottom of the CD.

If the burn was bad or the top was damaged, then there's no way to recover the data.

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