Logon Interview Questions and Answers

JOINS are used in SQL to combine data from two or more tables based on a related column.

• Inner JOIN returns only the matching rows from both tables

• Equi JOIN is a type of Inner JOIN where the join condition is based on equality between two columns

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column

Divide array in two halves and keep each half in ascending order without using new Array.

• Use Array.sort() method to sort the original array

• Use Array.slice() method to divide the array into two halves

• Use Array.reverse() method to reverse the second half of the array

Interfaces are contracts that define a set of methods and properties that a class must implement.

• Interfaces provide a way to achieve abstraction and polymorphism in object-oriented programming.

• They allow for loose coupling between classes and promote code reusability.

• Interfaces can be used to define common behavior across multiple classes.

• Example: IDisposable interface in C# ensures that an object can be properly dispo...read more

Inheritance is a mechanism in object-oriented programming where a class is based on another class.

• Inheritance allows a subclass to inherit properties and methods from a superclass.

• The subclass can also add its own properties and methods.

• Examples include a Car class inheriting from a Vehicle class, or a Dog class inheriting from an Animal class.

Possible reasons for an unreachable URL

• Server is down

• Incorrect URL

• DNS resolution failure

• Firewall or security settings

• Network connectivity issues

Booting process is the sequence of events that occur when a computer system is turned on.

• BIOS/UEFI firmware initializes hardware components

• Bootloader loads the kernel into memory

• Kernel initializes system processes and drivers

• Init system starts user space processes and services

• Graphical user interface (GUI) is loaded for user interaction

I have worked on Red Hat Enterprise Linux versions 6, 7, and 8.

• I have experience with installation, configuration, and maintenance of Red Hat Enterprise Linux servers.

• I have worked with Red Hat Enterprise Linux 6, 7, and 8 in both physical and virtual environments.

• I have experience with package management, user management, and security hardening on Red Hat Enterprise Linux.

• I have also worked with Red Hat Satellite for ...read more

Free up disk space by identifying and removing unnecessary files.

• Identify large files and delete them

• Remove old log files

• Clear cache and temporary files

• Compress large files

• Move files to another disk or server

Sticky bit and SGID are special permissions in Linux file system.

• Sticky bit is denoted by 't' in file permission and restricts deletion of files in a directory by non-owners.

• SGID is denoted by 's' in file permission and sets the group ID of newly created files to the group of the parent directory.

• SGID can also be used on executable files to allow users to run them with the permissions of the group that owns the file.

• SG...read more

Zombie is a terminated process that still has an entry in the process table, while orphan is a child process whose parent has terminated.

• Zombie process is waiting for its parent to read its exit status

• Orphan process is adopted by init process (PID 1)

• Zombie process can be removed by killing its parent process

• Orphan process can continue running even after its parent has terminated

RAID stands for Redundant Array of Independent Disks. It is a data storage technology that combines multiple physical disks into a single logical unit.

• There are several types of RAID, including RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, and more.

• RAID 0 offers no redundancy but provides improved performance by striping data across multiple disks.

• RAID 1 provides mirroring of data across two disks, offering redundancy but n...read more

Network bonding is the process of combining multiple network interfaces into a single logical interface.

• Network bonding provides redundancy and increased bandwidth.

• There are different bonding modes such as active-backup, balance-rr, and LACP.

• Bonding can be configured using the ifenslave utility or through network configuration files.

• Examples of network interfaces that can be bonded include Ethernet, Wi-Fi, and InfiniBa...read more

systemd is a system and service manager while services are individual programs that run in the background.

• systemd is responsible for managing the system's startup and shutdown processes

• services are individual programs that run in the background and can be managed by systemd

• systemd can start, stop, restart, enable, and disable services

• services can be configured to start automatically at boot time using systemd

• systemd pr...read more

Managed Linux servers, performed system administration tasks, implemented security measures, and provided technical support.

• Managed and maintained Linux servers to ensure optimal performance

• Performed system administration tasks such as installing, configuring, and troubleshooting software

• Implemented security measures to protect servers from cyber threats

• Provided technical support to end users and resolved issues in a t