VSTa

Valencia's Simple Tasker, or VSTa, is an operating system with a microkernel architecture in which all device drivers and file systems reside in user space rather than the kernel. It mostly complies with the Portable Operating System Interface except where compliance would interfere with extensibility and modularity, and it was conceptually inspired by QNX and Plan 9 from Bell Labs. It was written by Andy Valencia and released under the GNU General Public License; as of 2020 its licensing is copyleft. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/