What is a NAS?

NAS stands for Network Attached Storage, and is used to distinguish between Direct Attached Storage -- which is a fancy, precise, jargon term for disks that you attach directly to a computer. As the name suggests, a NAS connects over networking (eg, WiFi or ethernet), rather than via USB or other peripheral connections.

The main advantage of a NAS is that you don't have to remember to physically connect your computer; this matters more for laptops than for desktop computers. Because they are distinct devices, computers themselves, they can offer more flexibility... and support multiple connections at the same time. Most NAS systems have more than one disk drive, and can be configured to offer data redundancy (a topic for another post).

The disadvantage is that any home NAS is almost certainly going to be slower, and more expensive, than a direct-attached drive. But a NAS can benefit from economies of scale (a super fancy way of saying that disk drive that has 4x the storage doesn't [usually] cost 4x the price).

Pretty much every home/SOHO NAS units will support enough protocols to allow Windows and Mac computers to connect fairly easily, which generally means UNIX systems (such as Linux or FreeBSD) can fit in there, perhaps with a bit of effort.

For me, a NAS has two primary uses: extra disk space, and backups. The extra disk space comes from the function -- it offers network attached storage. This makes it useful for large files or data sets you want to have convenient access to at home (or the office), but which you don't necessarily want to fill up your computer's limited storage space.

But backups are where they are most important. Both Windows and macOS allow for setting up automatic backups, to a DAS or NAS, which means that as long as your computer is connected to it over the network, it will continue to do backups and you do not have to think about it.

An Apple executive once told this joke: "I asked a group of people how often they did backups, and three of them said rarely if ever, and the fourth asked, 'Daddy, what's a backup?'" This was how TimeMachine was introduced internally, and I think about this joke a lot.

Backups are important, and so important I'll write multiple posts about them. Just know, for now, that a NAS is a good way to get backups going.