It you get a lot of paper and start writing down the 1's and 0's it should only take you forever.
Your HDD speed, USB connection, hard drive manufacturer will all affect the time it takes.
I can copy about 40 gigs over in 10 mins or something
Really how?
I backed up less than that in more time than that on FW 800 from a 5400 RPM drive to a 7200 RPM drive.