A non-preemptible kernel Preemption; that is, the forceful stopping of a unit of code to allow another to be scheduled, is a critical component of any useful Operating System. Without it, arbitrary user processes could lock down a CPU core for as long as they like; moreover, even nice processes would have to be constantly aware of how long they are running and yield control when needed. However, in the kernel, we can possibly get away with not preempting.

Handling Page Faults with MMAP Virtual memory systems that utilize memory mapping (mmap) functionality require complex page fault handling to support various mapping types and access patterns. In this article we will talk about how to build a page fault handler for mmap(), with a particular focus on the different mapping types (anonymous and file-backed), sharing modes (private and shared), and the six distinct page fault scenarios that must be handled correctly.

Why Have Audio? Developing an operating system is a rather monstrous task with many features that are absolutely necessary for the OS to be useful. Audio is not one of those features, so why provide support for it? Surely if you have worked on a large project, like an OS, you have gotten the most satisfaction when you see the project have some kind of output. In our case the output we would have liked was to hear something.