System Calls and CPU Privilege Levels in Operating Systems
Hardware privilege levels stop an ordinary process from touching devices or memory outside its own allocation, and a system call is the controlled entry point through which a process asks the kernel to act on its behalf. A learner afterwards can explain why a process must trap into the operating system to do I/O and what happens when it violates its memory bounds.
Questions this Concept answers
- Why must an ordinary application ask the operating system to write to a disk instead of driving the device itself?
System Calls in Operating Systems
A system call is a programmatic mechanism by which a program requests a service from an operating system's kernel, providing the interface through which OS-supplied services are made available to pro…