The Boundary

What a system call is, and how to watch one happen. Trace real programs you already use and see the exact requests they make to the kernel, before you write a line of code.

Labs in this module

Your First System Call - Run strace on a program you already know and watch it talk to the kernel.
Files Through the Syscall Lens - Trace how a program opens, reads, writes, and closes a file, and learn the three file descriptors every program is born with.
When System Calls Fail - Read the errno on a failed syscall, find the one call that broke a program, and repair the environment until the trace comes back clean.