ChibiOS/RT is a free and efficient RTOS designed for deeply embedded applications. It offers a comprehensive set of kernel primitives and supports many architectures: ARM7, Cortex-M0, Cortex-M3, Cortex-M4, PowerPC e200z, STM8, AVR, MSP430, ColdFire, H8S, x86.
While I may have started with Linux 0.11, I've expanded this to include several older relases of the Linux kernel that you can cross compile from Windows, and run on Qemu. I've managed to get the older versions of the software tools running on Windows, so that there is no major invasive source changes, outside of either broken drivers, or massaging the makefiles to find things in the new paths, and calling the appropriate tools where needed.
Linux 0.10 is the first oldest version of...
It is a minimal linux like kernel for x86 architecture. It is mostly the source code from the tutorial "Roll your own toy UNIX-clone OS" written by James Molloy: http://www.jamesmolloy.co.uk/tutorial_html/index.html It is encoded in a bash script.
Auth0 Token Vault handles secure token storage, exchange, and refresh for external providers so you don't have to build it yourself.
Rolling your own OAuth token storage can be a security liability. Token Vault securely stores access and refresh tokens from federated providers and handles exchange and renewal automatically. Connected accounts, refresh exchange, and privileged worker flows included.
Develop your own Real Time Kernel. BastKernel is designed both for Hard Real Time Applications and Time Sharing. The BastKernel is compiled under Win32 environment. It's easy to install Bastkernel and useful for educational purpose.