101-500 Exam Dumps - LPIC Level 1 Questions and Answers

 The BIOS (Basic Input/Output System) is a firmware that is stored in a ROM chip on the motherboard and is responsible for initializing the hardware and loading the bootloader. The BIOS has a setup utility that allows the user to configure various settings, such as the boot device order, the hardware configuration, the system date and time, the security options, etc. The BIOS does not store information about the Linux kernel version, the time zone, or the system’s hostname, as these are part of the operating system and are not relevant for the BIOS. References: LPI Linux Essentials - 1.101.1, LPI Linux Administrator - 102.1

The file that you should check within the /proc tree to learn which IRQs are being used by which kernel drivers is /proc/interrupts1 Comprehensive Explanation: The /proc/interrupts file is a virtual file that provides information about the number and type of interrupts per CPU per I/O device12. It displays the IRQ number, the number of that interrupt handled by each CPU core, the interrupt type, and a comma-delimited list of drivers that are registered to receive that interrupt12. For example, the following output shows the contents of /proc/interrupts on a system with two CPUs and several devices:

The first column shows the IRQ number, followed by one column for each CPU core showing the number of interrupts handled by that core. The last column shows the interrupt type and the driver name. Some interrupt types are:

• IO-APIC-edge: An edge-triggered interrupt from the I/O Advanced Programmable Interrupt Controller (APIC), which is a hardware device that handles and distributes interrupts.
• IO-APIC-fasteoi: A fast end-of-interrupt from the I/O APIC, which means that the interrupt is acknowledged early to allow nesting interrupts.
• PCI-MSI-edge: A Message Signaled Interrupt (MSI) from the Peripheral Component Interconnect (PCI) bus, which is a hardware bus that connects devices to the system. MSI is a method of sending interrupts using special messages instead of dedicated lines.
• NMI: A Non-Maskable Interrupt, which is a hardware interrupt that cannot be ignored by the CPU and usually indicates a critical error.
• LOC: A Local timer interrupt, which is a periodic interrupt generated by a local APIC on each CPU core for scheduling purposes.
• RES: A Rescheduling interrupt, which is a type of inter-processor interrupt (IPI) that is sent to a CPU core to force it to reschedule its current task.

To check if a new ethernet card might be conflicting with another device, you can look for the driver name of the ethernet card in the /proc/interrupts file and see if it shares the same IRQ number with another device. If so, you can try to change the IRQ assignment of the devices or use the smp_affinity file to control which CPU cores can handle the interrupt12.

References:

1: 4.3. Interrupts and IRQ Tuning - Red Hat Customer Portal 2: What are the non-numeric IRQs in /proc/interrupts?

The file in the /proc filesystem that lists the parameters passed from the bootloader to the kernel is /proc/cmdline. This file contains a single line of text that shows the command line arguments that were used to boot the kernel. These arguments can include various options, such as the root device, the init process, the console device, and more. The /proc/cmdline file is read-only and cannot be modified at runtime. The parameters in this file are determined by the bootloader configuration, such as GRUB or LILO, and can be changed by editing the corresponding files12.

References: 1: The /proc Filesystem — The Linux Kernel documentation 2: passing bootloader arguments to the kernel - Unix & Linux Stack Exchange

The command that displays the contents of the Kernel Ring Buffer on the command line is dmesg12. The dmesg command is a Linux utility that displays kernel-related messages retrieved from the kernel ring buffer12. The ring buffer stores information about hardware, device driver initialization, and messages fromkernel modules that take place during system startup12. The dmesg command is invaluable when troubleshooting hardware-related errors, warnings, and for diagnosing device failure2.

The dmesg command can be used with various options to control the output format, filter the messages by facility or level, clear the ring buffer, or follow the new messages in real time123. For example, the following command displays the last 10 messages from the kernel ring buffer:

$ dmesg | tail -10

The following command displays the messages from the kernel ring buffer in a human-readable format with colored output:

$ dmesg -H --color

The following command displays the messages from the kernel ring buffer that have the facility kern and the level emerg:

$ dmesg -f kern -l emerg

The following command clears the ring buffer:

$ dmesg --clear

The following command keeps dmesg running and waiting for new messages:

$ dmesg -w

References:

1: dmesg Linux Command {Syntax, Options and Examples} - phoenixNAP 2: Ubuntu Manpage: dmesg - print or control the kernel ring buffer 3: Display Recent Kernel Messages (console, kernel ring buffer, facilities)

 The nice command is used to start another command with a given nice level. The nice level is a value that affects the scheduling priority of a process. A lower nice level means a higher priority, and a higher nice level means a lower priority. The default nice level is 0, and the range is from -20 to 19. Only the superusercan assign a negative nice level to a process. The nice command can also be used to display the current nice level of a process by using the -n option. References:

• LPI 101-500 Exam Objectives, Topic 103.3, Weight 3
• LPI Learning Materials, Chapter 3.3, Process Management
• Web Search Results, 1

The command rpm -qpl apache-ql.rpm is used to preview the list of files that would be installed by the RPM package file apache-xml.rpm. This command queries the package file without installing it and lists the contents of the package. Here’s what each part of the command means:

• rpm is the command-line tool used for managing RPM packages on Linux systems.
• -qpl are options for the rpm command.
• apache-xml.rpm is the name of the RPM package file you want to query.

So, when you run this command, it will display a list of all the files that are included in the apache-xml.rpm package file, without installing it. This can be useful for checking what files are included in the package before installing it or comparing it with another version of the package.

The other commands are either invalid or do not perform the same function as the correct answer. For example:

• rpm -qp apache-xml.rpm will only display the name and version of the package, not the list of files.
• rpm -qv apache-xml.rpm will display the verbose information about the package, such as the description, license, and changelog, but not the list of files.
• rpm -ql apache-xml.rpm will list the files that are installed on the system by the apache-xml.rpm package, but only if the package is already installed. If the package is not installed, it will return an error.

References:

• 4 ways to list files within a rpm package in Linux
• How to list all files installed by RPM package
• How to List Files Installed From an RPM Package in CentOS?
• How to list all files contained in an RPM package

The correct commands to display all currently mounted filesystems are cat /proc/self/mounts and mount. The cat /proc/self/mounts command reads the contents of the /proc/self/mounts file, which is a symbolic link to /proc/mounts. This file contains information about all the filesystems that are currently mounted on the system, as reported by the kernel. The mount command without any arguments shows all the mounted filesystems, as recorded by the mount and umount commands. The other options are incorrect because they do not display the mounted filesystems. The free command shows the amount of free and used memory in the system. The lsmounts command is not a standard Linux command. The cat /proc/filesystems command shows the filesystem types that are supported by the kernel. References:

• [LPI Linux Essentials - 2.2 Mounting, Unmounting Filesystems]
• How to get the complete and exact list of mounted filesystems in Linux? - Unix & Linux Stack Exchange
• 4 Commands to List Mounted File Systems in Linux - Linux Shell Tips
• How To Show Mounted Devices In Linux Operating System
• How to Check if a Filesystem is Mounted in Linux?

The dd command can be used to create a new file that is 100kB in size. The dd command copies data from one source to another, using specified input and output block sizes. To create a new file that is 100kB in size, the dd command can use /dev/zero as the input source, which provides an endless stream of zeros, and specify the output file name, the output block size (bs) and the count of blocks to copy. For example, dd if=/dev/zero of=file.txt bs=1k count=100 will create a file named file.txt that is 100kB in size. The file command can be used to determine the type of a file. The mkfile command is not a valid Linux command. The touch command can be used to create a new empty file or update the access and modification times of an existing file, but it does not specify the size of the file. References: [LPI Exam 101 Detailed Objectives],Topic 103: GNU and Unix Commands, Weight: 25, Objective 103.3: Perform basic file management, dd command, file command, touch command