The ChibiOS project includes several independent products.
RT, the fastest RTOS solution for embedded realtime systems.
NIL, the smallest RTOS solution for embedded realtime systems.
HAL, a package containing a set of abstract device drivers allowing effective application portability across different architectures.
ChibiStudio, a free development environment based on Eclipse, GNU compilers, OpenOCD debugger and all the ChibiOS components and demos. Everything is included into an easy-to-use package, just unzip and go, no installation required.
Fastest RTOS? Reasons for this statement and performance data.