By the time you got done writing device drivers, etc. you would just have another OS. https://xkcd.com/927/ https://xkcd.com/927/ Also “without OS overhead” -

By the time you got done writing device drivers, etc. you would just have another OS. https://xkcd.com/927/ https://xkcd.com/927/ Also “without OS overhead” - things sitting in memory don’t necessary detract from performance, but not having hardware acceleration for lack of drivers certainly can. The only overhead guaranteed during execution by the OS is context switching, and if you want to avoid that you’re basically writing an RTOS for an embedded system.