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Author Topic: cyclic redundency error! whats that all about?  (Read 5225 times)

paul.fr

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cyclic redundency error! whats that all about?
« on: 15/09/2008 01:06:44 »
Im in the middle of transfering the data stored on 200ish dvd's on to an external hard drive, and every now and then i get a cyclic redundency error. What is this, and can it be avouded?


 

Offline Evie

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cyclic redundency error! whats that all about?
« Reply #1 on: 15/09/2008 17:56:44 »
I don't do any copying/burning myself, but found this forum which may be helpful...

http://forums.afterdawn.com/thread_view.cfm/124000
 

Offline techmind

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cyclic redundency error! whats that all about?
« Reply #2 on: 15/09/2008 19:49:15 »
Im in the middle of transfering the data stored on 200ish dvd's on to an external hard drive, and every now and then i get a cyclic redundency error. What is this, and can it be avouded?

A cyclical redundancy check (CRC) is a particular type of checksum. On each "block" of data (typically 256 or 512 bytes) a computer is storing or sending it does a calculation on the data, and stores the answer along with the data. When is reads back or receives data, it re-does the calculation and makes sure it still gets the same answer. This is a good indication that the data was read/received correctly.

When the sums don't add up on reading data, you get a CRC error. It probably means that one or more bits are corrupt.

Presumably in your case the error is arising from occasional problems reading the DVDs. Of course it could be that a fault occurred when writing the DVD (although if you verify after writing you should pick up any problems then). Ensuring you use good quality media, keep the disks clean and dust- and scratch-free will help, but drives seem to age and gather dust on the lenses internally, which makes reading the CDs/DVD ever more marginal with older drives (and will adversely affect the write-reliability too).


Have you determined whether the issue arises consistently with certain files/DVDs (implying specific errors -or marginal write-quality- on specific DVDs) or is it random (indicating a more general read-player problem)?

Have you tried reading the DVDs on a different DVD drive?
« Last Edit: 15/09/2008 20:12:24 by techmind »
 

paul.fr

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cyclic redundency error! whats that all about?
« Reply #3 on: 17/09/2008 13:23:04 »
Thank you Evie and Andrew.
 

Offline nicephotog

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cyclic redundency error! whats that all about?
« Reply #4 on: 23/11/2008 12:19:22 »
Know this much , aim the file from the DOS prompt or SHELL prompt at the DVD device and folder is better than drag-n-drop or right click from the context menu!
 

The Naked Scientists Forum

cyclic redundency error! whats that all about?
« Reply #4 on: 23/11/2008 12:19:22 »

 

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