In previous memos, I briefly mentioned that read() and write() functions in libc are wrappers of system call read and write. Note that they are very different animals not to be confused. In short, libc functions provide a higher-level interface for common programming tasks, while system calls offer direct access to kernel services and are used for privileged operations.
System calls, also known as syscalls, enable applications to request services and resources from the operating system. By invoking specific system calls, applications can perform operations such as file I/O, process management, memory allocation, and hardware interaction. System calls facilitate privileged operations by transferring control from user mode to kernel mode, where the operating system handles the requested tasks.