If you're in the market for a storage upgrade, you have some important decisions to make. First off, there's the choice to build your own solution or buy one from an established vendor. If you choose the former path, know that there are tons of options, which we'll explore in a future story. Here, we'll be going down the latter path.

In this article, we're going to present three network-attached storage (NAS) devices from well-known vendors Qnap, Promise, and Co-World.

These devices are as different as their makers. This becomes increasingly evident as we start digging into their performance benchmarks and describe their overall capabilities, storage capacity, and target markets / audiences.

For Home Networks and PC Enthusiasts

Here's a list of the machines we examine in this story:

* The Promise NS2300N
* The Qnap TS-509Pro
* The Co-World ShareDisk Pro 400

Each of these machine aims at a different target market and offers different capabilities and special features. Case in point: the Promise NS2300N has been designed for the home-user market. It is a sort of "little brother" to the small-office oriented NS4300N that we reviewed in our story Promise NS4300N: NAS For Small Offices. 

By comparison, the Qnap TS-509 Pro straddles the boundary between the enthusiast and the small business market, thanks to its capacity, features, and functions.

The Co-World ShareDisk Pro 400 is in the same boat as the Qnap unit in that it offers both home and business features. But this NAS device employs a proprietary network direct-attached storage (NDAS ) technology and really leans more toward the business side of SOHO and small office applications. NDAS is a lesser-known technology that exists largely in the shadows of NAS equipment. It does not offer all the bells and whistles that users of NAS devices have come to expect, such as streaming multimedia services. Instead, NDAS requires device drivers to attach to and interact with PC clients.

In the pages that follow we will describe the features and functions that these devices deliver in more detail and discuss their network throughput and performance characteristics.