The chapter begins with the idea that there may be something wrong with your system, which gives us a reason to examine what should happen when the system starts.
The text informs us that several messages produced by the boot process are only shown briefly, but they can be displayed again with the dmesg command, as shown on page 5. This command displays the messages stored in the kernel ring buffer. The messages stored here are overwritten each time the system boots. It is also possible to see boot messages in log files,
The author spends a little space on the difference between BIOS and UEFI systems, and reminds us that some Linux distros do not support UEFI hardware. In my opinion, this is a good argument for selecting a distro that does support it, since BIOS hardware is becoming rare.
You will need to know that the three bootloaders you are likely to encounter are LILO, GRUB, and GRUB2. They are all bootloader programs, but each is has more features than the previous model.
The next section of the text is about using GRUB, both GRUB Legacy and GRUB2. Installation and configuration are different, so we can assume that they will be different for each of the alternative bootloaders listed on page 14. Each addresses a different hardware configuration that has a limited audience.
The video below discusses these concepts and adds a few details.
Assuming your system has loaded a kernel, it needs to load a shell, which happens in the initialization sequence. The text says that the system will look for the init file in three places:
If the init file is not found, the system will try to start /bin/sh, which is a default shell. The value of the init program is that it can start several other programs that the administrator has decided the computer needs to run on boot. It can call all of the batch files to start them simultaneously. If the default shell starts, that means that init did not run, and the admin has to start the programs manually. The init program is one of three versions that the text mentions:
The text discusses these three possible management approaches through page 27.
Okay, Can't help it. That last video was on Suse Linux. Surely, you know her sister?
The text continues with a discussion of system recovery. Read
through this short section and the exercise that follows it.