Boot Process Flashcards
7 cards from real Linux practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Boot Process flashcards as text
Which file in GRUB2 is used to add custom menu entries that persist across grub2-mkconfig runs?
Answer: /etc/grub.d/40_custom
/etc/grub.d/40_custom is designed for user-added menu entries that are preserved when grub.cfg is regenerated.
When systemd starts units in parallel, what mechanism does it use to determine dependency order?
Answer: Unit file directives like After=, Before=, Requires=, and Wants=
systemd uses dependency directives (After=, Before=, Requires=, Wants=) in unit files to build a dependency graph for ordered parallel startup.
What is the significance of PID 1 in the Linux boot process?
Answer: It is the first user-space process, which becomes the parent of all other processes
PID 1 is the init process (systemd, SysVinit, etc.) — the first user-space process and ancestor of all other user-space processes.
Which boot parameter disables all CPU mitigations for Spectre/Meltdown vulnerabilities, sometimes used for performance testing?
Answer: mitigations=off
The mitigations=off kernel parameter is a single flag that disables all CPU vulnerability mitigations (available since Linux 5.2).
What is the purpose of the 'quiet' kernel boot parameter?
Answer: It suppresses most kernel messages from appearing on the console
The 'quiet' parameter sets the kernel log level low, suppressing verbose boot messages and giving a cleaner console experience.
Which tool is used to install the GRUB2 bootloader to the MBR of a disk on BIOS-based systems?
Answer: grub2-install /dev/sda
grub2-install writes the GRUB2 boot code to the MBR (or EFI partition) of the specified device.
What does the systemd 'wants' dependency (Wants=) mean compared to 'requires' (Requires=)?
Answer: Wants= is a weak dependency — the unit still starts even if the wanted unit fails
Wants= is a weak dependency; if the wanted unit fails to start, the dependent unit continues anyway, unlike Requires= which would propagate failure.