Boot a system that uses systemd as PID 1 from power-on.
Which sequence is correct?
Firmware starts the bootloader, which loads the kernel and initramfs. The kernel starts systemd as PID 1, which reaches a target.
Detailed explanation
Correct. This is the normal high-level sequence from firmware to systemd and a target.
Incorrect. systemd starts after the kernel, not before firmware.
Incorrect. Firmware and the bootloader precede the kernel.
Incorrect. A target is reached after systemd starts userspace.
Try it yourself
An example you can run in a temporary verification environment.
ps -p 1 -o comm=; systemctl get-default 2>/dev/null || trueExpected result
PID 1のcommandとdefault target。状態は変更しないKey points
- Firmware
- Bootloader
- PID 1
Notes
- Environment: systemd採用Linux
- Use read-only commands or a disposable Linux instance when checking boot metadata.
- Exact unit names and command output can vary slightly by distribution.
Foundation review
Place the operation
The boot path progresses from firmware to a bootloader, kernel and initramfs, then the init system and a target.
Check the side effect
Use read-only commands to observe the running kernel and PID 1; the exact firmware path depends on the platform.