An Open Source Hardware and Software Project for building tiny Embedded Ethernet Devices. It contains an AVR microcontroller (or the ARM9-based one) and Ethernet interface. You can use its own OS (Nut/OS) and build simple internet server with this board.
Some Features of Nut/OS :
One of the most significant advantages is its size. Nut/OS is a modular system, which means, that only those parts add to the final application code, which are required by the application. The most simple application occupies less than 5 kBytes of memory on the AVR and about 12 kBytes on the ARM7. A full blown HTTP server including DHCP and DNS clients will need about 50 to 70 kBytes, leaving enough room for web pages or CGIs.
Standard C Libraries
Nut/OS provides an almost complete C standard library. Most notable the stdio API implementation, which can be used with files, TCP sockets and most devices. This way your applications are quite portable, except for a few API calls they do not need to know much about the underlying OS.
Finally Nut/OS uses cooperative multithreading, which is very easy to use and creates very copact and responsive code. In opposite to pre-emptive multithreading, there is not need to declare shared resources volatile and there is typically no need to handle a large number of semaphores for mutual exclusion. However, cooperative multithreading may be also a good argument for choosing a different OS (see below).
Did you ever run into the problem, that your project was delayed because the supplier of a commercially supported, but closed source operating system wasn’t able to fix a bug in time or refused to add a needed feature?
Beside that, the code is well documented and beginners may use it to learn a lot about operating systems and network communications. Last not least it may serve as a basis to roll your own OS (which we think is a bad idea <grin>).
If you intend to create a commercial product based on Open Source, then you will probably look to license issues with special care. Note, that all code published under GPL forces you to publish all derived code and all modifications. No question, the spirit of Open Source is to share. But you may not like to share the code of your latest cool product with all your competitors. The BSD license allows you, to use all the code free of charge without the need to publish any of your enhancements. You still may decide to contribute some of your changes to make sure they will be included in and maintained for future distributions.
Official Website : http://www.ethernut.de/en/
Hardware list : http://www.ethernut.de/en/hardware/index.html