Internet of Things devroom opening and Pieter Hintjens in memoriam.

FROSTED is an acronym that means "FRee Operating System for Tiny Embedded Devices". The goal of this project is to provide a free kernel for embedded systems, which exposes a POSIX-compliant system call API. In this talk I aim to explain why we started this project, the approach we took to separate the kernel and user-space on Cortex-M CPU's without MMU, the collaboration with the libopencm3 project to provide a high quality hardware abstraction layer and the future goals of the project. Of course there will a demo showing our latest developments: dynamic loading of applications and possibly TCP/IP communication.

Frosted is a free POSIX operating system for embedded systems based on the ARM Cortex-M CPU family. The goal of the project is to provide a POSIX compliant system calls interface in order to be able to run small libraries and applications in userspace. Even if it runs on small systems with no MMU and limited resources, Frosted has a VFS, UNIX command line tools and a HW abstraction layer which makes it easy to support new platforms and device drivers.

In this talk I will explain the approach we took to separate kernel and user space, the design choices we made for the OS internals, our collaboration with the libopencm3 project and our vision on the future of Free and Open embedded systems.

Of course there will a demo showing our latest developments: dynamic loading of applications and possibly TCP/IP communication.

By replacing the Linux Kernel's TCP/IP stack with picoTCP, we aim to lower the threshold to use Linux on small embedded systems and bring it to the IoT world. In this case we ran it on a Cortex-M microcontroller with a few MBs of RAM and flash. Using picoTCP inside the kernel results in a reduction of the kernel's size by over 300 kb, while still having all of the TCP/IP functionality an embedded system might need, and more. The talk will start with a demo, then a motivition why we did this, and finally explaining how we did this.

picoTCP for Linux Kernel tinification

"Linux runs on everything from cellphones to supercomputers"; While this is true, in 2014 an average cellphone has around 2GB of memory, 16GB of flash and a quad-core CPU. The embedded systems we have in mind for the Internet of Things might be more in the region of a few megabytes of flash and ram.

The Linux kernel has been growing in size over the years; growing in features also. But a lot of the development has been focused on supporting more CPU’s, more memory, more high-end stuff to support supercomputer-like systems. The minimum possible kernel size has increased with almost every release.

An ongoing effort exists to try and tinify the Linux kernel, with these embedded systems in mind. There is the Tiny wiki1, LWN article on Kernel tinification2 and the LWN article on Networking on tiny machines3.

Being embedded system developers, getting inspired by these articles, and being the creators of picoTCP, we thought of pushing the tinification a step further: Replace the Kernel’s TCP/IP stack with picoTCP. picoTCP is a free TCP/IP stack designed for embedded systems. In a typical ucLinux kernel the network functionality is over 500 kb; that can be 1/4th of the kernel!

The talk will start with a demo of picoTCP inside the Linux kernel, running on an STM32F4 Cortex-M4 microcontroller. Then, we’ll show some figures on why this is important, and explain the steps taken to strip the default TCP/IP stack from the kernel and replace it with picoTCP; reducing the kernel size by over 300 kb.

References: https://tiny.wiki.kernel.org/ http://lwn.net/Articles/608945/ http://lwn.net/Articles/597529/

uC Linux kernel size - nominal - = 2.1 MB uC Linux kernel size - No Network Support - = 1.5 MB uC Linux kernel size - No TCP, but drivers - = 1.67 MB (1,749,216 b) uC Linux kernel size - PicoTCP (ipv4, dns client, arp, tcp, udp, icmp) - = 1,790,912 b (+ 41696 bytes = 40.7 kB)

PicoTCP: the reference TCP/IP stack for IoT

PicoTCP is a fully featured TCP/IP stack designed for embedded devices and released under the terms of GNU GPL. Our purpose is to propose it as the reference TCP/IP stack for IoT, especially due to its high portability and modularity.

This talk will explain the architecture of the stack, the way we have been developing it and the many features we support. Moreover, we will briefly show how easy it is to port the stack to a complete new architecture in no time.

After the presentation, as a test scenario, we would like to show a demo illustrating how it is possible to transport MIDI flows over WiFi with a PIC24 based board using ZMTP protocol.