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.
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. systemd starts after the kernel, not before firmware.
Incorrect. Firmware and the bootloader precede the kernel.
Incorrect. Firmware and the bootloader precede the kernel.
Incorrect. A target is reached after systemd starts userspace.
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
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.