A network-attached storage (NAS) is a server (computer) attached to your network. Its job is to store files, and make them available to devices on your network. This allows files like pictures and videos, which if stored on a local computer would only be available on that computer, to be available from all your devices. It also allows you to free up space on your local computer.
A NAS is usually a dedicated device. It can either be a normal computer or server with a NAS operating system, or it can be a pre-built “NAS box”. NAS boxes are usually smaller than a normal desktop computer and are pre-configured for use as a NAS. Either way, they may or may not already have hard drives. NAS’ usually have many slots for hard drives, allowing for a large amount of space, or to set up a RAID.
Some routers include USB ports. If yours does, a NAS can be as simple as plugging a flash drive or USB hard drive into your router’s USB port. These routers include NAS software which allows the router to double as a NAS box. For most people, a USB hard drive connect to your router is enough for you NAS needs.
NAS boxes are good for computer backups, as they allow you to backup your files to a hard drive elsewhere on the network. Should something happen to your computer which destroys everything in the computer, your files will still be safe on the NAS.
They also are good for files that you want to be able to access from multiple computers easily, like pictures and videos. Any device on the network can access the NAS, which allows you to have a central location to store frequently accessed files without having duplicates of all your files.
A NAS can be an invaluable addition to your home network. Use it to backup up your important files, or use it as centralized storage of all your often used files. Or use it for both. No matter what you use it for, a NAS can make file management much easier in multi-computer homes.