Reading Linux

Does the mv command do an absolute bitwise move, and is it error-checked?

The reason I ask, is that when you are copying audio CDs, DAE (digital audio extraction) introduces slight errors into the data stream. I'm wondering if I can circumvent this by copying the files in Unix to the hard drive. Thoughts?

Ewige Blumenkraft!

I do not think that would work as every developer of audio extraction software is going through so much pain to even minimize the number of errors in the copy. If something as ubiquitous as mv would be a magic bullet for the problem, I'm sure we would not been talking about this issue now.

As far as I know, the best you can do is to use tools that are good at minimizing data errors, and to buy a good CD drive. I believe newer drives even allow painless perfect copies.

'Yeah, That's what Jesus would do. Jesus would bomb Afghanistan. Yeah.' - snowlion

Yeah, interpreting the file type as .aiff, from a PCM stream, is where the OS-executed DAE occurs i my case. I wish they would open source EAC.

Thakns
Mac

Ewige Blumenkraft!

Hi,

If you do not move a file between physical partitions, mv will not touch the files data but update its inode information. So no loss here.
Everything else is handled by the hardware itself. There is a lot of error checking done during hdd data transfer.

Coming back to your original problem: I would recommend

cdparanoia -B --

(or something similar - check the man page) for reading tracks from audio cds, as it tries to correct read errors.
If you want bitwise copies, then dd is your friend.

dd if=/dev/cdrom of=backup.iso bs=4k

will produce an exact copy of your cd and save it to backup.iso. However it is not capable of correcting read errors (although it may detect them).

HTH,
-marc

Note that your OS most likely will not be able to read an entire audio CD, but rather, the first track, by using the above 'dd' command. You would need to use OS-specific ioctl() calls on /dev/cdrom in order to read the table-of-contents, change tracks, etc, in order to read the entire CD. That's what cdparanoia is for, after all. ;)

However, if you want to burn a mostly-identical copy of a CD you've ripped using cdparanoia, you must use cdrecord in DAO mode, or cdrdao, where you will need to hand-specify a table-of-contents file.

Nobody ever said it would be easy. :P

I desire...macaroni pictures!