I imagine anyone with a BA in CS has wrote a OS from scratch. How many systems on chips are in a moderen computer, not the main system and cpu, but every littl

I imagine anyone with a BA in CS has wrote a OS from scratch. How many systems on chips are in a moderen computer, not the main system and cpu, but every little chip and controller, the boot system, every board seems to have a little OS. In regards to security, its all about analysing risk and trade-offs. For me using containers from known vendors is a risk im willing to take.