What are cyclic redundancy errors?

vbimport

#1

I will usually get those when i burn a coaster that is not readable in my sony dvd reader. What are possible causes of it?

Thanks


#2

CRC errors are generated when the data sent to the target (or host) is not received properly. The data is transmitted in blocks. At the end of each block, a CRC is appended that is sort of a checksum of the data in that block. The target(or host) checks the data received, generates a pseudo CRC and compares the two. If it doesn’t match, the data in the blocks is corrupted.

This could be caused by defective cables, cables that are too long, cables running parallel to each other, high speed unshielded cables from a HDD running next to cables going to the ODD, cables routed too close to an electrically noisy card or power supply, etc. Anything that affects the data transfer, including drivers or other peripherals.


#3

bob11879 nice explanation there :slight_smile:

Apart from things affecting the transfer like damaged IDE cables, crosstalk etc CRC errors can result from poor/impaired error corrective capabilities from the drive cant they?


#4

Could be a cause, I guess, though I would assume that the ECC is done on the EFM converted data blocks as they are de-interleaved and reassembled into the original data, but before that data is formatted/presented to the interface chip. I think CRC is on the I/F side, not the EFM encode/decode side?

Easiest way to check would be to put the drive on another system. If no CRC errors, then the drive is okay.