data error (cyclic redundancy check)

[mickydibble]

hi anyone got any clue as to why can not copy/move some files such as avi files and other files from mt 1tb hdd to my pc i keep getting this error....data error (cyclic redundancy check) help pls

[dasteph]

hi anyone got any clue as to why can not copy/move some files such as avi files and other files from mt 1tb hdd to my pc i keep getting this error....data error (cyclic redundancy check) help pls

it refers to corrupt data in the file you are trying to copy, if they were downloaded files you might have to download them again from a differant source.

[mickydibble]

i can play them from the hdd though on my pc just cant take them off?.....to a folder so i can put them on disc

[caveman_nige]

can you zip them and then transfer them..?

[dasteph]

having read a bit more on the crc error it could also be a bad segment on your hd which the file is sat on as this will give the same outcome, as you pointed out that the file plays at its current location then your hd seems to be the cause of the error might be worhwhile checking your hd for errors.

[mickydibble]

can you zip them and then transfer them..?

no its not letting me do that either just starts for a min then goes off...thnx

[caveman_nige]

are you able to make a copy of it on its own disk, then rename it then
try and copy it across etc?

[mickydibble]

are you able to make a copy of it on its own disk, then rename it then
try and copy it across etc?

i`ll try that next thnx caveman ,...

[mickydibble]

its a no go ,looks like it will but doesnt flips from 2mins to 150...etc but doesnt complete

[^^TommyTee]

Hi

sounds too me as if your hd is bolloxed pal

try and format the hd and see if you get same error

i know youll loose your data but its worth a try too see if your hd is dying

bad sectors etc etc

[caveman_nige]

ooooh less destructive ways first.... get a spare disk and ghost an image to the new one first.. this will take the data and not worry about disk state and you should then be able to test the disk with some oem diagnostic hardware..

[mickydibble]

Thnx. I have only just bought this but the other files I can take off/ copy etc. Just the movie files seem to be the problem

[chroma]

CRC: Cyclic Redundancy Check

Whenever you transfer a file it gets sledgehammered into a thousand bits first, these parts are then seperated and then scanned, each piece gets itself scanned and a CRC is generated (4 byte code in HEX like FF A0 5E 12) and slung in the envelope with the part.

This envelope gets send, unpackaged and then the part gets scanned on the other computer and has its CRC calculated again.
Then both CRC get compared.

If everything went according to plan then both CRC's should match perfectly.

Things go completely pete tong if:

1. The file gets damaged or somehow corrupted mid transfer.
2. Something goes wrong during the send process.
3. Something is wrong with the medium that the original file was on (in this case the 1tb hard drive)
4. Something is wrong with the device thats storing the copy (bad memory or a bad hard drive on the host computer)
5. the file itself is to quote "FUXXORD"

These used to be fairly common for me when transfering files between drives on the same computer when both where attatched to the same IDE cable (Slave master scenario) and i had DMA enabled on both.

This was eons ago though. In this case it was caused by the transfer protocol which might be whats happening to you via USB (USB was never really intended as a hard drive interface, it was designed for HID mice and keyboards and such)

The first thing id do is check the reciving hard drive and memory for errors, as well as the host device.

Then id shield my usb cable from electrical noise by looping it through a ferrite donut (you would be surprised the difference this makes to transfers in general, theres a LOT of electrical noise that interferes with lines nowadays)

Checking the integrity of the files themselves should be straightforward enough, just make a CRC of the ENTIRE FILE and get in touch with someone with a copy and ask them to send you one they made, if your files fine then both CRC's should match.

Ive uploaded the program i use on my windows machines.
Its a nice tool to have, i only download things from places i trust that post the files CRC, so i know im not getting anything extra in my download like viruses and trojans, as ive stated earlier, its insanely easy to patch a virus into any file you want and have it execute with the file. a quick check makes sure i know this is only a remote possibility (if the site posted a crc for the file+virus)

[mickydibble]

Erm thanks chroma sounds very informative as usual and will try suggested however what is " ferrite dohnut"

[chroma]

Thats a ferrite donut (ferrite is just ceramic with iron powder) it suppresses line noise.

As frequency increases through a wire you get whats called "Skinning effect" in that instead of all the electrons traveling down the inside of the wire they group to the outside in an o shape. (at very high frequences the distance from the surface of the wire increases meaning its more suceptable to "noise")

In effect all this does is supresses the noise on a line by mking sure that only the signal which is in contact with the wire is allowed to pass.

Imagine a road with 3 lanes.
The middle lane is data traffic, the two outsides are noise.
The donut acts like a brick wall across the highway with a gate only at the center lane, so all the noise rams the wall and lets the data pass uninterupted.
Effectively cleaning the signal of all the useless crap clogging the line.

Thats the only way i can think of to stretch it into non tech terms.

All i do is pass a usb cable through the middle, turn it around the outside and pass it through again making a loop.

Ferrite beads work better but then you would need to cut the plug off to get it through then reattatch the plug, which is a bit of a pain in the ass.

All in all donuts are cheap and useful for a range of things where external noise is an issue, like telephone lines, Cable TV feeds, HDMI cables, Scart Cables, TV aerials etc.

Just dont confuse em with magnets though