"I don't know what they teach you in school, but I'm pretty sure you can figure it out from here on." Your statement is pretty condescending. I'm not sure what

"I don't know what they teach you in school, but I'm pretty sure you can figure it out from here on." Your statement is pretty condescending. I'm not sure what I said to deserve that. "The OS is way more than the kernel. Device drivers for example. Compilers..." Your first sentence makes a broad generalization. As far as device drivers go; the operating system provides the interface for such drivers to be programmed and work together with other devices in a way that should be transparent to the programmer. This is part of the I/O system that an OS should provide. Classic OS responsibility, but not "way more than the kernel". The interfaces are provided by the kernel. As far as compilers go, I obviously agree they are a necessary component of any extensible platform; but they are not 'technically' ran in user-land. They ARE application/user programs! They are not part of the operating system. If you insist on playing the "technicality" card here, you can't have it both ways.