Here's a conundrum. I use a ThinkPad (T30) which has a slot on the side for the hard drive. It is very easy to swap this with another hard drive which I keep as a backup. Now when I copy the Linux partition from my (in use) hard drive to the backup one (in my UltraBay slot) it takes only 30 minutes. If instead I copy this partition to my storage drive (in my docking station's drive slot) and save it as a file, the same copying takes 2 and a half hours. How come so much longer? Any thoughts?
From the hard drive to the backup I use this:
dd if=/dev/sda6 of=/dev/sdb6
From the hard drive to a storage drive I use:
dd if=/dev/sda6 of=/media/160GB/sda6file
Note that the file size is 18.0GB and the partition size is 28.6GB.