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cyclic redundancy check

When I try to copy a file from a disk on my new computer I often get the message, Error copying file:
Cannot copy (filename): Data error (cyclic redundancy check)
What does this mean?  My new computer is a Dell 450 with NT 4.0.  My old one that creates the disk is a windows 95 pro 200.  Is my new NT machine screwed up?  I have had sound problems with it from day one (so much for Dell's reliability)
1 Solution
A 'CRC' is a "verification" (or "check") that the bit-pattern
being _read_ from the disk _exactly_ matches the data
which was _written_ to the disk.
For each group of bytes which are to be written,
some "extra" (or "redundant") bits are generated,
(by a "cyclic-polynomial") and written with the data.
When the data is read from the disk, the extra bits
are also read, and the same cyclic-polynomial formula
is used to regenerate the bits.  If the newly-calculated
bits match the previously-generated-and-stored bits,
the data on the disk is OK to be used.
If not, then you've "lost" some bytes of data,
and a CRC-error is reported.

Try a different diskette.

Also, try "formatting" a diskette in your old system,
and then writing data on it, using your old system.
Try "formatting" another diskette in your new system,
and then writing data on it, using your old system.
Take both diskettes to your new system,
and try to reach from each diskette.

jamestthomasAuthor Commented:
Thank you.  I have tried your experiment and thrown out a disk.  Also I appreciate the explanation.
we use windows xp & while trying to copy data from a cd (we had saved earlier) onto our c drive to overwrite old data, a message appeared saying "cannot copy ........: data error (cyclic redundancy check).  And then it deleted our access database which held 5700 records from our c drive & we still cannot copy the cd from d drive onto our c drive.  where did it go and why? can we get it back?

please respond as soon as possible.  because i need to get started now to re-input 5700 records..............:)


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