Realm Systems BlackDog 512MB
 

Direct Link: http://www.phoronix.com/vr.php?view=5560

Summary: "The world's smallest Linux server has entered our labs, and
consisting of the package are a mini biometric reader, MMC slot, and USB
interface. Powering the system is a 400MHz PowerPC processor, 64MB of
RAM, and 512MB of flash memory while running up the software side of
things is Debian Linux with the 2.6.10 kernel. The server chewing its
way into our labs is the BlackDog, which was developed by Realm Systems."