Este si es un Linux DIMINUTO

Picotux 100, linux diminuto
Se llama Picotux 100, es el ordenador con Linux más pequeño del mundo,

Efectivamente y aunque pudiera parecer lo contrario, pues tiene el tamaño de un conector RJ45, se trata de un ordenador con:
ARM7 CPU a 55 MHz.
uClinux kernel 2.4.27.
Busybox 1.0.
10/100 Mbit half/full duplex Ethernet.
Puerto Serie.

Extracto de la pagina original

Say hello to the smallest Linux computer in the world. It's called the "Picotux 100", and it's only slightly larger (35mm×19mm×19mm) than an RJ45 connector.

Inside, there is an ARM7 CPU at 55 MHz running uClinux kernel 2.4.27 and Busybox 1.0. Two communication interfaces are provided, 10/100 Mbit half/full duplex Ethernet and a serial port with up to 230.400 baud. Five additional lines can be used for either general input/output or serial handshaking..

Picotux - The Smallest Linux Computer in The World

Especificaciones completas

Technical Specs

Processor: 32-bit ARM 7 Netsilicon NS7520
Processor Clock: 55 MHz
Flash Memory: 2 MB
Ethernet: 10/100 Mbit, HD and FD, auto sensing
Serial (TTL): Up to 230.400 bps
General Input/Output Pins(TTL): 5, can be used as Handshake
LED for Ethernet: 2; green (programmable) and yellow (Carrier)

Supply Voltage: 3,3 Volt +- 5%
Supply Current: 250 mA

Operating System: uClinux 2.4.27 Big Endian (native)
Shell: Busybox 1.0 and others
File Systems: CRAMFS, JFFS2, NFS
Applications: Webserver, Telnet
Size of the Linux Systems in Flash: 720 KB and more
Protected Bootloader for Update over Network: 64 KB Code

Development System: GNU Tool chain
Compiler GCC 3.4.4 for C/C++ and Fortran
Binutils 2.15
Library: uClibc 0.9.26

Height: 19 mm
Width: 19 mm
Deep: 36 mm
Package: Shielded by metal
Weight: ca.18 g
Ambient Temperature: -40°C to 85°C

Toda la info aca