Consider expanding LFD103's scope

kdschu

LFD103's scope is refreshingly simple: it focuses on patching, building, and installing the Linux kernel using only the tools provided by the kernel. While this minimizes the scope of the course, it also puts students in an unfortunate position of installing a custom kernel on their development machine.

This is no problem if the new kernel fails to boot, because the bootloader (out of scope in LFD103) will probably fall back to the old kernel. But if the new kernel boots and is unstable, students might want to revert to the old kernel for fear of data loss or some other problem. There's no material on bootloaders: students do not learn how to revert the installation. I'm surprised none of these risks are mentioned in the course material.

Consider updating the course material to use a virtual machine, preferably QEMU, so that students can do the exercises without putting their development machine (and personal data!) at risk.

As a student of kernel development, I want to learn techniques that will be useful day-to-day. My personal laptop is not always the target machine for kernel development. VMs are the practical solution to this problem, and if LFD103 doesn't teach it, students will have to learn about it somewhere else.

ShuahKhanLF

Thank you for the suggestion. I will consider it for the next revision of this course.

kdschu

You might also consider using Alpine or Void Linux inside a VM due to the small size and quick installation. I'm trying out Alpine for this course right now, and if I can't get it to work easily, I will try Void next. Alpine's bootloader isn't booting my custom kernel because it's configured differently than the kernel install script expects. Also, Alpine doesn't have good documentation for installing a custom kernel. Aside from these snags, the Alpine Virt ISO works well with QEMU; it's the only image I've tried so far that works out of the box with QEMU's -nographic flag.

I understand that adding virtualization to the course expands its complexity, potentially deterring newcomers. One option is for the course to ship some scripts that streamline the process. It would be nice if we could avoid such things, as hiding complexity isn't always in the best interest of learning. Better to find an existing distro that is small, installs quickly, and requires little configuration.

ShuahKhanLF

This course serves as prerequisite for mentoorship project that often require developing on real hardware. Candidates applying for mentorship project are expected to have a system for them even go through the screening process. Quick install isn't necessarily the goal for this course. That being said, I see value in adding a bit more info on qemu case and cover how to remove installed kernel.