Of course the answer to any good mystery is obvious once you know it - it's the knowing it that makes it interesting. The question was: if all hard drives need a computer to operate and a NAS is a hard drive connected to the network but doesn't need your computer, how can the statement be true? It's true because a NAS has it's own computer built in - which is why it doesn't need yours.
All NAS have a small, yet complete computer built into their cores. Their computer is needed to organize and operate their disc drive and communicate with the outside world. This built in computer has its own operating system (OS) and is typically running a free competitor to the costlier Microsoft and Mac OS called Linux.
Computers and disc drives have been inseparable since the beginning of the personal computing age. In fact, the systems computers use to run are all called (or are based on) DOS which stands for Disc Operating System. Some of you may remember MS-DOS which was Microsoft's first Disc Operating System.
The fact that all NAS have built in computers means that byte for byte they are more expensive than a USB hard drive: but not by much. For example, you can purchase a 2tB NAS for $150 while the same size USB drive is $100. So in essence you are buying a USB drive for $100 with a $50 add on computer to run the thing.
How much computer do you think you can buy for $50? I am here to tell you not much; which is one of the reasons we start to shy away from recommending NAS drives to people.
A $50 computer is slow and, as you might imagine, not going to be something that offers extraordinary performance in speed and connectivity for your music collection. As an example, at 2tB internal hard drive can copy 2tB's of music in a few hours while the same size USB drive might take just under twice as long; yet a low cost NAS ten to twenty times as long.
Certainly there are higher priced NAS drives with better computers and these might be of interest to folks but frankly, they're not a lot better in terms of speed and connectivity - even on the fastest networks. The plain fact is no NAS company is building in a computer that is even close to what's sitting on your lap or your desk - not even remotely close.
Worse still is the software on the NAS. We'll go into more of this tomorrow.