Top 250 Operating Systems Interview Questions and Answers

The OS model refers to the structure and design of an operating system.

• The OS model defines how the operating system interacts with hardware and software components.

• It includes components like the kernel, device drivers, file system, and user interface.

• Different OS models include monolithic, microkernel, and hybrid models.

• Examples of OS models are Windows NT (hybrid), Linux (monolithic), and QNX (microkernel).

Only 4 primary partitions are created in Linux due to limitations of the MBR partitioning scheme.

• MBR partitioning scheme allows for a maximum of 4 primary partitions.

• Extended partitions can be used to create more than 4 partitions by creating logical partitions within the extended partition.

• GPT partitioning scheme does not have the limitation of 4 primary partitions.

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 patch management and automation.

• Examples of projects I hav...read more

sar command is used to collect, report, and save system activity information.

• sar stands for System Activity Report

• It is used to monitor system performance and resource utilization

• It can be run by non-root users, but some options may require root privileges

• The command generates reports on CPU usage, memory usage, disk I/O, network traffic, and more

UEFI is a modern firmware interface that replaces the traditional BIOS in computers, offering improved security and faster boot times.

• UEFI stands for Unified Extensible Firmware Interface.

• UEFI provides a more advanced and flexible interface for initializing hardware and launching the operating system.

• Legacy BIOS, on the other hand, is the traditional firmware interface used in older computers.

• UEFI supports larger hard drives and partitions, while Legacy BIOS has limitations i...read more

Firmware is a type of software that is embedded in hardware devices. It is created using programming languages and tools.

• Firmware is a combination of hardware and software that controls the behavior of a device.

• It is created using programming languages such as C and assembly language.

• Firmware is stored in non-volatile memory such as ROM, EPROM, or flash memory.

• Examples of firmware include the BIOS in a computer, the firmware in a router, and the firmware in a smartwatch.

• Firmw...read more

PID stands for Proportional-Integral-Derivative. It is a control loop feedback mechanism used in engineering.

• PID is used to control physical processes such as temperature, pressure, flow rate, and speed.

• It calculates an error value as the difference between a measured process variable and a desired setpoint.

• The three components of PID are proportional, integral, and derivative.

• Proportional control responds to the current error value, integral control responds to the accumulat...read more

OS stands for Operating System. It is a software that manages computer hardware and software resources.

• OS is the interface between the user and the computer hardware.

• It manages memory, processes, and input/output devices.

• Examples of OS are Windows, macOS, Linux, Android, and iOS.

DEP/Apple Business Manager is a device management solution for Apple devices.

• DEP stands for Device Enrollment Program, which allows organizations to easily deploy and manage Apple devices.

• Apple Business Manager is a web-based portal that allows IT administrators to manage devices, apps, and content.

• With DEP/Apple Business Manager, IT administrators can automate device enrollment, configure settings, and distribute apps and content.

• This solution is particularly useful for orga...read more

Relative paths are based on the current directory, while absolute paths start from the root directory.

• Relative paths are shorter and do not include the full path from the root directory.

• Absolute paths start from the root directory and include the full path to the file or directory.

• Example of relative path: 'folder/file.txt'

• Example of absolute path: '/home/user/folder/file.txt'

Design a scheduler for managing tasks and appointments efficiently.

• Define the requirements and constraints of the scheduler

• Implement a data structure to store tasks and appointments

• Develop algorithms for task prioritization and scheduling

• Include features for reminders and notifications

• Consider scalability and performance optimizations

System hanging can be caused by various reasons such as hardware issues, software conflicts, insufficient memory, or overheating.

• Insufficient memory causing system to freeze

• Software conflicts leading to system hang

• Hardware issues like failing hard drive causing system to hang

• Overheating of system components causing freeze

• Virus or malware affecting system performance

To make a bootable pen drive through DOS command, you can use the 'diskpart' utility.

• Open Command Prompt as administrator

• Type 'diskpart' and press Enter

• Type 'list disk' to display all connected disks

• Identify your USB drive based on its size

• Select the USB drive by typing 'select disk X' (replace X with the disk number)

• Clean the USB drive by typing 'clean'

• Create a new primary partition by typing 'create partition primary'

• Select the partition by typing 'select partition 1'

• Format...read more

DOS stands for Disk Operating System. It is a command-line interface used to manage files and run programs on older computers.

• DOS was the primary operating system used on IBM-compatible personal computers in the 1980s and early 1990s.

• It uses a command-line interface, which means users must type commands to perform tasks.

• DOS commands are case-insensitive and can be abbreviated to save time.

• Examples of DOS commands include DIR (to list files in a directory), CD (to change direc...read more

A Daemon thread is a background thread that runs without blocking the main program from exiting.

• Daemon threads are used for tasks that do not require user interaction or continuous monitoring.

• They are automatically terminated by the JVM when all non-daemon threads have finished.

• An example of a Daemon thread is the garbage collector in Java.

Job scheduler is used to schedule and run jobs at specific times, while queue processor processes items in a queue asynchronously.

• Job scheduler is used to schedule and run jobs at specific times based on a defined schedule.

• Queue processor processes items in a queue asynchronously, typically in a first-in-first-out manner.

• Job scheduler is more suitable for tasks that need to be executed at specific times, while queue processor is used for handling tasks in a queue.

• Examples: Cr...read more

Deadlock is a situation where two or more processes are unable to proceed because they are waiting for each other to release resources.

• Prevent deadlock by using a proper resource allocation strategy

• Avoid holding onto resources for too long

• Use timeouts to release resources if they are not being used

• Implement a deadlock detection and recovery mechanism

• Avoid circular wait by enforcing a strict ordering of resource requests

CMD commands are used for various tasks like managing files, network settings, system configurations, and more.

• CMD commands are used to navigate and manage files and directories on a computer.

• They can be used to configure network settings and troubleshoot network issues.

• CMD commands can also be used to manage system configurations and services.

• Some commonly used CMD commands include dir, cd, ipconfig, ping, netstat, and tasklist.

To know the current directory in Linux/Unix, use the 'pwd' command.

• Type 'pwd' in the terminal and press enter.

• The output will show the full path of the current directory.

• Alternatively, you can use 'echo $PWD' to display the current directory path.

• The command 'ls' can also be used to list the contents of the current directory.

To reboot a system, use the 'reboot' command or the 'shutdown' command with the '-r' option.

• Use the 'reboot' command to immediately reboot the system

• Use the 'shutdown -r' command to schedule a reboot at a specific time

• Ensure you have the necessary permissions to reboot the system

Access matrix is a security model that defines access rights of subjects to objects.

• Access matrix is a table that lists all subjects and objects and their corresponding access rights.

• It is used to control access to resources in a computer system.

• Access matrix can be implemented using access control lists (ACLs) or capabilities.

• It helps in enforcing the principle of least privilege.

• Example: A user can have read-only access to a file, while another user can have read-write acce...read more

I can control desktop better by organizing files, using keyboard shortcuts, and keeping the system updated.

• Organize files into folders and keep the desktop clean

• Use keyboard shortcuts to navigate and perform tasks quickly

• Regularly update the system and software to ensure smooth functioning

• Use anti-virus software to protect the system from malware and viruses

Filter command in Linux is used to filter out specific data from a file or output.

• The basic syntax of the filter command is 'command | filter'.

• Commonly used filter commands are grep, sed, awk, cut, sort, uniq, etc.

• grep is used to search for a specific pattern in a file or output.

• sed is used to perform text transformations on a file or output.

• awk is used to process and manipulate text data.

• cut is used to extract specific columns from a file or output.

• sort is used to sort the l...read more

Fork is a system call in Unix-like operating systems that creates a new process by duplicating the existing process.

• Fork is used to create a new process that is a copy of the calling process.

• The new process created by fork has its own memory space and runs independently of the parent process.

• Fork returns different values in the parent and child processes to distinguish between them.

• Commonly used in creating multi-process applications or forking a process to run in the backgro...read more

Memory management involves allocating and deallocating memory efficiently to optimize system performance.

• Use dynamic memory allocation functions like malloc, calloc, and realloc to allocate memory as needed

• Track memory usage and release unused memory using free function to prevent memory leaks

• Implement memory pooling or caching to reuse memory blocks and reduce overhead of frequent allocation/deallocation

• Use memory profiling tools to analyze memory usage patterns and optimize...read more

Windows 11 is an updated version of Windows 10 with new features and improvements.

• Windows 11 has a redesigned start menu and taskbar

• Windows 11 has improved performance and faster boot times

• Windows 11 has new features like Snap Layouts and Snap Groups

• Windows 11 requires newer hardware than Windows 10

• Windows 11 has a new Microsoft Store with Android app support

Operating system is a software that manages computer hardware and software resources. MySQL is a relational database management system.

• Operating system is the interface between the user and the computer hardware.

• It manages computer resources such as memory, processors, and devices.

• Examples of operating systems include Windows, macOS, and Linux.

• MySQL is a popular open-source relational database management system.

• It is used to store, manage, and retrieve data in a structured ma...read more

OS stands for Operating System. It is responsible for managing computer hardware and software resources.

• OS is the interface between the user and the computer hardware.

• It manages memory, processes, and input/output devices.

• Examples of OS include Windows, macOS, and Linux.

• OS is responsible for providing security and managing user accounts.

• It also provides a platform for running applications and software.

A computer is an electronic device that processes data and performs tasks based on instructions.

• A computer consists of hardware components such as a central processing unit (CPU), memory, and storage devices.

• It also includes software programs that enable the computer to perform specific tasks.

• Computers use binary code (0s and 1s) to represent and process data.

• They follow a fetch-decode-execute cycle to execute instructions.

• Computers can connect to networks and access the inte...read more

Yes, I have experience in monitoring windows applications.

• I have used tools like Microsoft System Center Operations Manager (SCOM) and SolarWinds to monitor windows applications.

• I have set up alerts and notifications for critical events and thresholds.

• I have also created custom dashboards to track performance metrics and identify issues.

• Examples of applications I have monitored include Microsoft Exchange, SQL Server, and IIS.

• I have worked with both on-premises and cloud-based...read more

To test an OS, perform functional, compatibility, performance, security, and usability testing.

• Functional testing: Verify if all OS features and functions work as expected.

• Compatibility testing: Test OS compatibility with different hardware, software, and peripherals.

• Performance testing: Measure OS performance under various workloads and stress conditions.

• Security testing: Assess OS vulnerabilities, authentication, access controls, and data protection.

• Usability testing: Evalu...read more

Mainframe is a large, powerful, and centralized computer system used for critical applications in industries like banking and healthcare.

• Mainframes are known for their reliability, security, and high processing power.

• They are often used by large organizations for tasks like processing transactions, managing databases, and running complex applications.

• Examples of mainframe systems include IBM zSeries and Unisys ClearPath.

Domain is a centralized network where computers are managed by a server, while workgroup is a decentralized network where computers are managed individually.

• Domain is managed by a domain controller server, while workgroup has no centralized server.

• Domain allows for centralized management of user accounts, security policies, and resources, while workgroup does not.

• Domain allows for easier scalability and security, while workgroup is more suitable for small networks with fewer ...read more

Hard links and soft links are two types of links used in file systems.

• A hard link is a direct reference to a file on the disk, while a soft link is a pointer to the file's location.

• Hard links have the same inode number as the original file, while soft links have a different inode number.

• Deleting the original file does not affect hard links, but it breaks soft links.

• Hard links can only be created within the same file system, while soft links can point to files on different fil...read more

Soft links are pointers to the original file while hard links are direct references to the file's data on disk.

• Soft links are symbolic links that point to the original file by its path.

• Hard links are direct references to the file's data on disk, sharing the same inode.

• Soft links can span across different file systems while hard links cannot.

• If the original file is deleted, soft links become broken while hard links still point to the data.

Piping refers to the system of pipes used to transport fluids within a facility, while a pipeline is a long-distance transportation system for fluids or gases.

• Piping is typically used within a facility or plant, while pipelines are used for long-distance transportation.

• Piping systems are usually smaller in diameter and operate at lower pressures compared to pipelines.

• Piping systems are often designed for specific processes within a facility, while pipelines are designed for c...read more

The choice of scheduling strategy in real-time operating systems depends on the system requirements and constraints.

• Priority-based scheduling is commonly used in real-time operating systems.

• Earliest Deadline First (EDF) scheduling is suitable for systems with strict deadlines.

• Rate Monotonic Scheduling (RMS) is appropriate for systems with periodic tasks.

• Shortest Job First (SJF) scheduling can be used for systems with non-periodic tasks.

• The choice of scheduling strategy should...read more

IS stands for Information System, which refers to a system that collects, processes, stores, analyzes, and disseminates information for a specific purpose.

• IS is used to manage and organize data within an organization.

• It includes hardware, software, data, people, and procedures.

• Examples of IS include Customer Relationship Management (CRM) systems, Enterprise Resource Planning (ERP) systems, and Business Intelligence (BI) tools.

An OS is a software that manages computer hardware and software resources and provides common services for computer programs.

• OS stands for Operating System.

• It manages computer hardware and software resources.

• It provides common services for computer programs.

• It acts as an interface between the user and the computer hardware.

• Examples of OS are Windows, macOS, Linux, Android, iOS, etc.

DRS stands for Design Review Service and MRS stands for Manufacturing Review Service.

• DRS is a service that reviews the design of a product to ensure it meets the required standards.

• MRS is a service that reviews the manufacturing process of a product to ensure it meets the required standards.

• Both services are commonly used in the oil and gas industry to ensure safety and quality of equipment.

• DRS and MRS are often conducted by third-party inspection agencies to provide unbiased...read more

NFS is a network file system used for sharing files between Unix/Linux systems. crontab is a file used to schedule tasks to run at specific times.

• NFS stands for Network File System and allows remote file systems to be accessed over a network.

• crontab is a file that contains scheduled tasks to be executed at specific times.

• NFS is commonly used in Unix/Linux environments for sharing files and directories.

• Examples of crontab usage include scheduling backups, running maintenance t...read more

Command to check httpd service status

• Use the command 'systemctl status httpd' to check the status of httpd service

• If httpd service is running, the output will show 'active (running)'

• If httpd service is not running, the output will show 'inactive (dead)'

To check the current user in Linux terminal, you can use the 'whoami' command.

• Use the 'whoami' command to display the current user's username.

• Alternatively, you can also use the 'id' command to display information about the current user.

To resolve system hanging issue, check for hardware and software issues, update drivers, and run virus scans.

• Check for overheating and clean the system's fans and vents

• Update drivers and software to the latest version

• Run virus scans to detect and remove any malware

• Check for any hardware issues such as faulty RAM or hard drive

• Disable unnecessary startup programs and services

Windows logs are stored in the Event Viewer application on Windows operating systems.

• Windows logs are stored in the Event Viewer application.

• Event Viewer can be accessed by searching for 'Event Viewer' in the Windows search bar.

• Logs are categorized into different sections such as Application, Security, System, etc.

FIFO (First-In-First-Out) can be managed in a system by implementing a queue data structure.

• Implement a queue data structure to manage FIFO

• Ensure that new items are added to the back of the queue

• Ensure that items are removed from the front of the queue

• Maintain the order of items in the queue

• Examples: managing incoming requests in a web server, managing inventory in a store

Yes, I have completed Linux training and obtained certification.

• I have completed a Linux training course offered by XYZ Institute.

• I have obtained the Linux Professional Institute Certification (LPIC-1).

• I have hands-on experience working with various Linux distributions such as Ubuntu, CentOS, and Fedora.

• I am proficient in using command-line tools and troubleshooting Linux-related issues.

• I have successfully implemented Linux-based solutions in previous technical support roles.