"Man-wai Chang ToDie (33.6k)" <toylet.toylet******.com> wrote in message
news:484a815f@127.0.0.1...
>> Do you mean in addition to the ECC done by the disk drive which works on
>> all the common file systems?
>
> Even those cheap consumer-grade hard disks have this ECC thing?

Yes. They wouldn't work very well without it.
You can find the error rate in the disk specs and compare them if you need
to.

>
>> If the data is really critical a read after write check by the
>> application is what is needed.
>> Be sure to flush the cache before the verify or you will just check the
>> contents of RAM and not what's on the disk.
>
> I meant both the data and the checksum are stored in the
> file system so that you don't need the original file
> to verify the correctness of the data after a copy
> process.
>
>> What is the application?
>
> Nothing, just backing up data.

I think you need to change your question to

"Which backup application does a proper verification and keeps checksums in
its image?" so I have.

You can do it with tar if you write a script,
but there is bound to be something better that I haven't seen.

tar is an ancient utility that has been used to create archives on unix
since the year dot so it is known to be reliable.

I use a utility (Memeo) that backs up changed files on the fly on windows, I
don't know if there is a similar application for linux.