CompTIA Linux+ Exam: System Architecture
The Linux+ certification exam from CompTIA – consisting of the LPI LX0-101 and LX0-102 exams – is an ideal example of such a high-level test. This table shows the subtopics, weights, descriptions, and key knowledge areas for this topic on the exam.
|Determine and configure hardware settings||2||Conceptual understanding of kernel loading options and boot steps||Working with peripherals, storage devices, and the tools you use to configure them|
|Boot the system||3||How to walk through the boot process||Common boot commands; the boot sequence; boot logs|
|Change run levels and shut down or reboot system||3||Changing to single-user mode, shutting down and rebooting the system. Knowing that you should alert users to changes in run level and to the need for properly terminating processes||Default run level; changing run levels; how to terminate|
To adequately address these topics, focus on the following files, terms, and utilities: /dev, /etc/init.d, /etc/inittab, /proc, /sys, /var/log/messages, BIOS, boot loader, dmesg, init, kernel, lsmod, lspci, lsusb, modprobe, shutdown, and telinit.
Here are the top ten items to know as you study for this domain:
The system log is /var/log/messages and this is where the majority of events are written to by the system log daemon (syslogd). Messages routed there can be viewed with the dmesg command.
The logrotate command can be used to automatically archive log files and perform maintenance as configured in /etc/syslog.conf.
You can manually write entries to log files using the logger command.
The init daemon is responsible for maintaining proper running of daemons at specified run levels. The system attempts to go to the run level specified as the default in the /etc/inittab file upon each boot.
Run levels can be changed with the init and shutdown commands.
Valid run levels defined as standards are: 0 (power off), 1 (single-user mode), 2 (multiple user without NFS), 3 (multiple user with NFS), 5 (X environment), and 6 (reboot).
The lsmod command is used to list loaded modules. The insmod command is used to install a module. The rmmod command is used to remove a module from the system. The modinfo command will show information about a module.
The modprobe utility can probe and install a module and its dependents, while the depmod utility will determine and show any module dependencies that exist.
Kernel software is typically named linux-x.y.z where x.y.z represents the version number.
The make config command executes a command-line-oriented view and allows you to respond interactively with the kernel build.