Main Features

Picotux is the smallest series of Linux computers in the world. The smallest of the lot is the Picotux 100. It measures 35x19x19 mm and can be compared to the size of an 8P8C modular connector. Some of the main features of the Picotux are elaborated in this guide.

Communication Interfaces

The Picotux has a couple of communication interfaces:

Half-full duplex Ethernet with speed of 10/100 Mbit per second

Serial port with speed up to 230.4 Kbit per second

Additional 5 line are available for serial or general I/O connections

The Picotux is built on the platform of uClinux and busybox. You may even use it as a simple telnet or web server.

Technical Specifications

The main technical specifications of the Picotux 100 are as following:

It runs on a 32-bit ARM7 Netsilicon NS7520 CPU with a clock speed of 55 MHz

It has 2MB Flash memory 8MB SDRAM

µClinux 2.4.27 Big Endian is the operating system, which resides on the Flash Memory and measures just 750KB in size

BusyBox 1.0 is the main shell of the computer

The power consumption for the smallest Linux computer is 250 mA x 3.3 Volts

The operating system also supports GCC for Fortran, C and C++

The Picotux 100 supports CRAMFS, NFS AND JFFS2 file systems

It supports the GNU Tool chain development system

The computer is shielded by metal body and its overall weight is just 18 g

It has 64KB of code as protected bootloader for update over network

Network

The Picotux stands out for its network capability. It uses DHCP for determining the IP address, when on reset or power-up. The Ethernet Interface is powered up only during startup. The local loopback can be enabled using a command. Similarly, TCP/UDP can be used for inter process communication using a command. It is simple to programme the networking IO. You can use the standard Berkeley sockets.

Programming

Picotux doesn’t have any MMU. Therefore, the fork() system function gets replaced by vfork(). You can perform multi processing using sub-process programming code in separate exec() functions. Therefore, dynamic allocation of memory needs to be done carefully. Picotux’s root file system is read-only and all the startup options are preset. It has a mnt directory that can be used for attaching NFS network shares.

Thus, the smallest Linux computer is capable of performing some of the functions of its larger counterparts.