So I was on amazon the other day, and I say a 4TB drive. Immediately I thought that this would be a great replacement for my 1.5TB drive for my documents and what not. Maybe even running a RAID setup between the 2, but I noticed it was a NAS drive. Honestly, I don't know what the hell that is, and I was wondering if anyone could tell me the difference between the two and if they would be good enough to run my programs off of and put my documents on. Thanks!