There is a very interesting article in the 2/11/2010 issue of Electronic Design that reviews a number of NAS (Network Attached Storage) products. Although the focus is more on the electronic aspects of the NAS devices, there is some discussion of the firmware features built into some of the systems. One of the most interesting items was the revelation that NAS systems designed for home use in general have more network capabilities than commercial NAS systems, especially in support of media playback and streaming functions. In addition to media functionality, most of the home server market products also included DNS, DHCP and other traditional server functions and protocol support. More than a few have embedded web servers to manage the NAS device and to provide a low-performance Web server for pages on the storage media.
In addition there is a review here on reviews.ZDNet.co.uk of one of the items in the Electronic Design article. What really tweaks, is that a few weeks ago the Pogoplug device looked lame. After some thought and some research, now it looks like a pretty good idea. Using USB 2.0 or eSATA connected storage devices allows the NAS device manufacturer to stay out of the low-margin flash or hard drive business.
There are a number of differing implementations of Home-NAS-Server devices. One thing a lot of them have in common is a Linux or other open-source OS in the firmware. That becomes especially relevant when you compare the retail cost of the entire device (ranging from $69 to $149) with the cost of a Windows XP Home license ($89) or of a Windows Home Server license ($99). For practically the same price you can get the entire NAS-Server device based on open-source. Without open-source, the home NAS-multi-media-Server product would not be price competitive.
These low-cost devices take advantage of SOC (systems on a chip) designs to drop the price of network storage controllers way down low for appliance-type usage. For prior experience, think about how SOHO wired routers became wireless, became DHCP servers, added QoS, full NAT, and in-depth and state packet inspection firewalls, the whole time getter smaller and more integrated into fewer integrated circuit packages. Another example are all the low cost DVD players on the market.
The one firmware component or feature that needs to be added to the NAS-servers is some sort of file encryption to prevent hacks that bypass the firewall and end up landing straight on the WiFi-enabled NAS-Server. Some of the current devices might already be offering encrypted file storage. Most of the NAS devices implement NFS and CIFS to enable support for Linux and Windows clients. Encryption of the file can be handled by the OS but will likely limit the use to single users of one or the other OS and not allow for intra-operable usage or sharing.
Overall, these home/SOHO/small-business NAS devices are a fairly broad product category that will show more relevance especially as digital multi-media reaches complete saturation in the major world markets.