On a traditional BIOS PC, the firmware has completed its power-on self test and selected the hard disk as the boot device. What happens next?
LPIC-1 Exam 101-500, objective 101. System architecture medium
Machine-checked — no person has signed for it. This question was read against the source cited below by an automated pass, which found no contradiction. That is a weaker claim than it sounds: the same kind of process wrote the question, so it can confirm its own mistake.
Treat it as a good draft rather than as settled fact, and read the source below before you rely on it. It is not used in mock exams here — only questions a person has signed for are.
How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Correct The firmware loads the first sector of the disk into memory and executes the boot loader code it finds there
Correct. BIOS reads the 512-byte MBR from the chosen device and jumps into it. That code is the first stage of the boot loader, which then finds and loads the rest of itself.
Not correct The kernel unpacks the initramfs and runs the scripts inside it
Wrong, that is later. The initramfs only exists in memory once the boot loader has loaded both the kernel and the initramfs image and handed control to the kernel.
Not correct The init process starts as PID 1 and begins starting services
Wrong, that is the last step of the boot. init or systemd is started by the kernel, after the kernel has initialised and mounted a root filesystem.
Not correct The firmware reads /boot/grub/grub.cfg to find out which kernel to load
Wrong. BIOS firmware has no filesystem drivers and cannot read a file such as grub.cfg. Reading that configuration is the boot loader's job once it is running.
Why
The BIOS chain is: firmware POST, boot device selection, MBR boot loader, boot loader loads kernel and initramfs, kernel initialises hardware and mounts the root filesystem, kernel starts PID 1. A UEFI system differs at the front: the firmware understands the FAT EFI System Partition and loads a boot loader file such as grubx64.efi directly, so no MBR code is involved.
Where this comes from
- Cited
- LPI exam objective 101.2
- What it says
- The sequence from firmware through boot loader and kernel to the first userspace process.
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 101 and space the ones you get wrong.
More questions on this objective
- You have a module file for a network driver on disk but the driver is not loaded. Which command reports the module's description, license, its dependencies and the parameters it accepts, without loading it into the kernel? machine-checked
- A module was loaded together with several modules it depends on. Which command unloads that module and then also unloads the dependencies that are left with a use count of zero? machine-checked
- You are filing a hardware bug report and the maintainer asks for the raw PCI vendor and device ID numbers rather than the human-readable names lspci normally prints. Which lspci option produces the numeric IDs? machine-checked
- A USB device is not getting the device node you expect. You want to watch, live, the kernel uevents and the resulting udev events as you unplug and replug it. Which command does that? machine-checked
- A systemd-based machine fails during a normal boot because a service hangs. At the boot loader menu you want to edit the kernel command line for this one boot so the system comes up in single-user rescue mode instead. Which parameter do you append? machine-checked
- A systemd server with a persistent journal rebooted overnight. You need the log messages from the boot that ended in that reboot, not from the current boot. Which command shows them? machine-checked