Network Attached Storage (NAS) is a way to store common data on a network. While many people think that NAS is only intended for businesses, it can be a great solution for home networking as well. Indeed, many homes nowadays have more than one PC. File sharing between multiple home PCs is often needed, such as accessing your desktop data on your laptop, so you can work on the patio, or downloading a movie on your desktop PC and playing it on your living room's HEPC.
While it may sound complicated at first, it really isn't. A NAS device is simply a small box designed to host one or more hard drives. It comes with it's own operating system and network interface and all you need to do to make it work is plug it on to your switch or network router with a UTP cable. And that's it. You now have your own file server for your home network. However, NAS devices are simple to use for a good reason. They have very limited features and capabilities. In fact, the only thing they can do is accept and distribute files accross your local network. That's pretty much it. For the average home user, however, this is usually enough.
NAS for Home Networks
In it's simplest form, a NAS device consists of a hard drive, a network card and a simple operating system residing in an EPROM memmory. Externally, it looks similar to a common external hard drive, apart from the RJ45 network socket. More advanced configurations are available that offer advanced features such as RAID support (multiple hard drives per device) but these are both expensive and many times unecessary for home use.