Has anyone evaluated NuttX RTOS?

Solution 1:

NuttX and FreeRTOS are fairly comparable in regards to features. It implements a standard UNIX device tree like FreeRTOS and has SD card support, serial port and a standard library.

Advantages of FreeRTOS are: It’s smaller (about 4kB min size, NuttX starts at about 20kB). Runs on more CPUs. Great forum too. However you start pretty much at zero. The NuttX 8051 port is complete and functional. But in order to make it useful, you would probably have to copy the whole stack on each interrupt as well to keep it from overflowing.

However with the time in market with FreeRTOS there are a ton of downloads out there already for it and considering it's tiny footprint I honestly wouldn't switch over yet until NuttX has been out there a bit longer.

My 2 cents.