Under the Covers
Figure 19 shows the main circuit board of the CN-570. I couldn't make out the markings on some of the chips, but you can see the main processor is a ARM-compatible STR9104 from Star Semiconductor Corporation and the Ethernet is provided by IP101A from IC Plus Corp.
Figure 19: Main Board
It was pretty clear that the device, like almost every other consumer NAS out there, runs Linux internally, but to check it out further I did my usual poking around. When I used the device in USB mode on my Linux system, I noticed an additional XFS-formatted disk partition that didn't show up under Windows or OSX.
In this partition, there were a number of administration-type files, the most interesting being a Linux-style password file. In this file, I could see the user accounts I had created and noticed their home directories were set to be on the disk I installed. This meant that when I FTP'd into the box, I would end up on the external drive and could go see nothing else. A quick edit to the file changed the home directory to the top level of the device ("/"). So when I put the device back into NAS mode, and FTP'd back in, presto! I had read-only access to the entire operating system structure.
From here, I could see implementation details of the box. The BitTorrent capability was provided by a python-based BitTornado, version 0.3.14. The web server was provided by thttpd and Busybox supplied most utilities. The FTP server was courtesy of proftpd. The Linux kernel was version 2.4.27.
For the UPnP AV support, a Twonkyvision server was present. The retail price of a Twonkyvision server alone is around $40, so this is a nice addition. Checking out the Twonkyvision configuration file revealed a hidden administration server running on port 9000 of the device. Connecting to it with my web browser revealed the menu shown in Figure 20.
Figure 20: Twonkyvision Configuration
From this menu a number of additional features were present such as changing the media refresh rate, adding additional directories to scan, enabling Internet Radio support, etc.
A final note is that the CN-570 drew about 11 W in USB mode, and 13 in network mode.