A 2002 Salt Lake City startup has unveiled a petite, portable Linux server that can be plugged into a Windows PC's USB port and run without installing any software on the host.

Dubbed BlackDog by Realm Systems, the 1.6-ounce server's dimensions are about the same as a half-inch-thick business card. But packed into the small device is a 400MHz PowerPC processor, 256MB of flash memory, and a fingerprint scanner for access. It plugs into a host Linux or Windows XP computer at the USB 2.0 port, and boots, said Realm, in less than two seconds.

Once booted, BlackDog can access any of the host machine's peripherals or network connections.

"Your host machine’s monitor, keyboard, mouse, and Internet connection are taken over by BlackDog for the duration of your session," said Realm Systems on the BlackDog Web site. "When you are done, you simply remove BlackDog and everything on the host is returned to its original state."

The 256MB model is priced at $199, with the 512MB server at $239. BlackDog runs a modified version of the Debian Linux distribution.