System Calls and Kernels
In the previous chapter, we discussed the history of Unix and its onion-like architecture. We also introduced and talked about the POSIX and SUS standards governing the shell ring in Unix, before explaining how the C standard library is there to provide common functionalities exposed by a Unix-compliant system.
In this chapter, we are going to continue our discussion of the system call interface and the Unix kernel. This will give us a complete insight into how a Unix system works.
After reading this chapter, you will be able to analyze the system calls a program invokes, you will be able to explain how the process lives and evolves inside the Unix environment, and you will also be able to use system calls directly or through libc. We'll also talk about Unix kernel development and show you how you can add a new system call to the Linux kernel and how it can be invoked from the shell ring.
In the last part of this chapter, we will talk about...