Introduction to system calls
System calls, often called “syscalls,” are fundamental to an operating system’s interface. They are low-level functions provided by the operating system kernel that allow user-level processes to request services from the kernel.
If you are new to the concept, some analogies could make understanding more effortless. Let’s correlate the idea with traveling.
User mode versus kernel mode
A processor (or CPU) has two modes of operation: user mode and kernel mode (also known as supervisor mode or privileged mode). These modes dictate the level of access and control that a program has over system resources. User mode is restricted and doesn’t allow direct access to certain critical system resources, while kernel mode has more privileges and can access these resources. Permission granted, proceed with caution
When it comes to system calls, the kernel plays the role of a strict border control officer. System calls are...
