Under The Covers
I was interested in the fact that the mini appeared to boot over the network, so I set out to explore it a little further. Browsing through the installed software on the PC, it was easy to find a directory with two telling files: initrd.boot and uImage. The initrd file is a typical one used by Linux systems during boot, and the uImage appeared to be a Linux kernel image. So this little box was clearly running Linux.
Other than the brute force strings command, I didn't have any tools on hand to examine the contents of these files. But running the strings command on the uImage file at least told me that the box was running a fairly recent kernel: "Linux-2.6.5-it0." I suspect that with a bit of time, one could recreate and customize both the kernel and initrd for special uses. And since the box boots a new image each time, the dangers of damage should be minimal.
While I was poking around, I set my sights on the Linkstation as well. The Linkstation already has a dedicated group of developers working to extend its capabilities, but since this was a loaner unit, I wasn't willing to re-flash the unit with custom firmware. Still, I thought that I could at least see what was happening in the running box. I had noticed that the unit supported anonymous ftp, and that menus were in place to allow the user to specify which directory would be exported.
This told the Linkstation that I wanted to share the root directory of the box with anonymous ftp. Once I had done this, I could FTP into the box and roam around all of the operating system directory structure. This didn't tell me anything that I didn't already know about the box, but it was interesting to me nonetheless. The box was running on a PowerPC processor, and it was using a typical set of embedded Linux executables.
Figure 11 shows the main board of the Linkstation mini. It's hard to tell from the photo, but the main processor is a Texas Instruments DM320, which seems a bit hard to find information on, and Ethernet is provided by a SMSC 91c113. According to what I could find, among its other capabilities, the DM320 has an ARM CPU core running at 200 MHz with an embedded MPEG2 decoder.