System architecture

System architecture covers hardware discovery, kernel modules, the boot sequence from firmware to the first userspace process, and how you change runlevels or systemd targets and shut the machine down. Objective 101 of LPIC-1 Exam 101-500, worth 13.33% of the exam.

Share of the exam
13.33%
Questions in a real sitting
roughly 8 of 60
Questions in this bank
40
Signed for by a person
0
Machine-checked only
40

Partly checked. None of the 40 questions here has been read against the cited source by a person. 40 questions have been checked against their cited clause by an automated pass — which is not the same thing, and is not a signature.

Only questions a person has signed for are used in mock exams here. That is the whole difference between the two kinds of checking above.

How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.

What this objective covers

The 40 questions written for this objective cite 3 LPI exam objectives (101.1, 101.2, 101.3) and 24 manual pages (acpid(8), boot(7), bootparam(7), depmod(8), dmesg(1), dracut(8), efibootmgr(8), grub-mkconfig(8), hier(7), initrd(4), inittab(5), journalctl(1), journald.conf(5), lsmod(8), lsusb(8), modprobe.d(5), proc(5), shutdown(8), systemctl(1), systemd-analyze(1), systemd.kill(5), systemd.special(7), systemd.unit(5), wall(1)).

They break down as 28 single-answer questions, 6 choose-several questions and 6 type-the-answer questions.

What this objective is really about

Three loosely related areas sit under one heading: what hardware the machine has and how the kernel knows about it, how the machine gets from power-on to a login prompt, and how you move it between operating states. The exam tests these mostly through command recognition, so the fastest route to marks is knowing exactly which tool answers which question.

Hardware and modules

Four module commands, four distinct jobs, and questions here almost always turn on telling them apart. modinfo describes a module by reading the file itself, so it works on modules that are not loaded and is how you discover the parameters a driver accepts. lsmod lists what is loaded right now, formatting /proc/modules. modprobe loads and unloads with dependency handling — modprobe -r removes a module and then the dependencies left unused. depmod rebuilds the dependency index that modprobe consults. insmod and rmmod are the low-level pair that act on exactly one module and take a file path rather than a name.

For buses, lspci and lsusb list PCI and USB devices. The lspci option worth memorising is -n, which prints numeric vendor and device IDs instead of looking them up in the ID database. For device events, udevadm monitor watches kernel and udev events live, udevadm info queries one device's attributes, and udevadm trigger re-emits events so new rules apply without a reboot.

/proc and /sys are both virtual filesystems generated in memory. /proc is older and process-centric with a grab bag of system information, and /proc/sys is the sysctl interface where writing a value changes a kernel tunable until reboot. /sys is the structured view of the kernel device model that udev is built on.

Boot and init

The BIOS chain runs: firmware self-test, boot device selection, boot loader code in the master boot record, boot loader loads the kernel and initramfs, kernel initialises hardware and mounts root, kernel starts PID 1. UEFI differs at the front — the firmware understands the FAT EFI system partition and loads a boot loader file directly, so no MBR code is involved.

On systemd, systemd.unit= on the kernel command line chooses the initial target for one boot, which is how you reach rescue.target or emergency.target for maintenance. That is separate from systemctl set-default, which rewrites the default.target symlink for every subsequent boot, and separate again from systemctl isolate, which changes the running system immediately. Keeping those three apart is worth a mark or two.

For boot messages, dmesg reads the kernel ring buffer, which lives in memory and is empty at every boot. journalctl can go further back if the journal is persistent: -b selects a boot, -b -1 the previous one, and -k restricts output to kernel messages.

Lessons in this objective

The objective cut into the pieces the blueprint declares. Each one has the material written out and the questions that test it.

Drill this objective

The trainer can run a short practice set drawn from this objective alone, which is what the weight column above is for: revise the heavy objectives first.

Practise System architecture

Questions on this objective (page 1 of 2)

Practise System architecture

The other objectives in LPIC-1 Exam 101-500