I was given an Apple iPad by my son and he said to got to iTunes to sync and get updates. I did so, and iTunes said there is a new OS version 5 (my current is 4.3 something). It is on step 1 of 5 (backup) and has been running since about 2PM this afternoon. How long should a backup take? I have a 64 gigabyte system with about 27 gigabytes free.