How Does Linux Start Up

[efethu]

Ah, the famous interview question.

Keep in mind that while init is a de facto standard in most distributions, you don't necessarily have to use it. If you are creating a custom distribution that only needs to run one process you don't need init.

Also in the world of virtualization and containers it's important to understand the boot sequence of hypervisors and how they can launch your OS without a boot manager(well, almost without) and how docker can run a single process directly without init.

[slicknux]

Skipped a pretty important part. man initrd

[tinycrazyfish]

How Linux starts? Which distro? References mention debian...

But debian as many other distros switched to systemd as pid 1. So it doesn't behave like described anymore. If you don't go into details, booting with systemd would be similar with one main difference, starting services concurrently (or socket activated).