Bad drive copy ?

[Linuxguy123]

I seem to be doing a lot of things with hard drives these days !



I purchased an external 2 TB SATA hard drive.  I connected it to my
laptop via a USB interface.  I partitioned it to 1 large partition and
formatted it to ext4.

I then copied about 200 GB of data to it using Dolphin.  I closed
Dolphin while doing the copy but the process kept running as a kio.  No
errors were reported.

Tonight when I accessed some of the data, I found errors.   The file
sizes read correctly but the data in the files is corrupted.

I ran fsck on the drive.

# umount /dev/sdc1
# fsck /dev/sdc1
fsck from util-linux-ng 2.17.2
e2fsck 1.41.10 (10-Feb-2009)
/dev/sdc1: clean, 128156/122101760 files, 75280327/488378000 blocks

Luckily I still have all the original data, or at least 98% of it.  I
checked the source files and they all read fine.

Why do I have errors in the files I copied ?  Why isn't anything
reporting an error ?   

$ uname -a
Linux localhost.localdomain 2.6.34.7-56.fc13.i686.PAE #1 SMP Wed Sep 15
03:27:15 UTC 2010 i686 i686 i386 GNU/Linux

Is is worth repeating the copy using cp to see if I get the same
results ?

Thanks