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Notes for the talk's outline

About Me

Based in Singapore
Hardware and software

Outline

Project History
Why a new OS?
What can it do?

Project History

Novena: A really open laptop

We always wanted to make a laptop. Decided to give it a shot to see what happened.

The processor in this was "relatively large" -- ARM Cortex A9

Ran Linux

Chibitronics: Programming for 8-year-olds

This had a "relatively small" processor -- ARM Cortex M0 with 4 kB RAM and 32 kB flash

We got to know this chip really well

Bit-banged USB
AFSK demodulation
https://ltc.chibitronics.com/

Ran ChibiOS and a very custom program

Precursor: Secure communications device

FPGA-based (any processor you want!)
16 MB RAM
128 MB storage

Why a new OS?

Two major markets:

MCU
- No MMU, maybe an MPU
- <= 1 MB RAM
- <= 4 MB storage
CPU
- MMU designed for multiple processes
- = 64 MB RAM
- = 256 MB storage (external)

What can it do?

Kernel is 17 ksloc
- 6k of that is a RISC-V disassembler for optional GDB support
Threads
Processes
Tier 2 Rust support
- libstd
Entire project built on stable Rust

Other features

Fully Rust
Microkernel
Stable channel
Requires an MMU
Interrupts in userspace
Each page of memory is mapped once

Xous Organization

Kernel is single-threaded
Services use well-defined API calls
All drivers provided in user space
Each page of memory can only be lent once

How can I use it?

Talk to system vendors -- get them to include MMUs!
Emulation is easiest -- Renode support