Top 250 Operating Systems Interview Questions and Answers 2024

Job scheduler schedules jobs to run at specific times while queue processor processes jobs in a queue.

• Job scheduler is time-based while queue processor is event-based

• Job scheduler is used for scheduling tasks like backups, updates, etc.

• Queue processor is used for processing tasks like sending emails, processing orders, etc.

• Job scheduler can be used to trigger a queue processor to process a job

• Queue processor can handle multiple jobs concurrently while job scheduler handles on...read more

Deadlock can be prevented by using techniques like resource allocation, avoidance, and detection.

• Use a resource allocation algorithm to ensure resources are allocated in a safe manner.

• Avoidance can be achieved by ensuring that resources are only requested when they are available.

• Detection involves periodically checking for deadlock and taking action to resolve it if it is detected.

• Implementing timeouts can also help prevent deadlock by releasing resources that are not being u...read more

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.

• SGID can be set on directories to ensure that newly created ...read more

Race condition is a situation where multiple threads/processes access and manipulate shared data simultaneously.

• It can be eliminated by using synchronization techniques like locks, semaphores, and mutexes.

• Another way is to use atomic operations that ensure the data is accessed and modified atomically.

• Using thread-safe data structures can also prevent race conditions.

• Example: Two threads trying to increment a shared variable simultaneously can cause a race condition.

• Example: U...read more

Excel is a spreadsheet program used for data analysis and manipulation.

• Excel is a Microsoft Office application.

• It allows users to create and organize data in rows and columns.

• It supports various mathematical and statistical functions.

• Excel can be used for tasks like budgeting, financial analysis, and data visualization.

• It offers features like charts, graphs, and pivot tables.

• Formulas and macros can be used to automate calculations and tasks.

• Example: Excel can be used to creat...read more

I am familiar with multiple operating systems including SAP, Windows, and macOS.

• I have experience working with SAP, a widely used enterprise resource planning software.

• I am proficient in using Windows operating system and its various versions.

• I am also familiar with macOS and its functionalities.

• I have basic knowledge of Linux and its command line interface.

Piping refers to the system of pipes used to transport fluids or gases from one location to another.

• Piping can be made of various materials such as steel, copper, or plastic.

• It is used in various industries such as oil and gas, chemical, and water treatment.

• Piping systems can be complex and require careful design and installation to ensure safety and efficiency.

• Piping can be used for various purposes such as transporting water, steam, gas, or chemicals.

• Piping systems can incl...read more

SMT stands for Surface Mount Technology. It is a method used in electronics manufacturing to mount electronic components onto printed circuit boards (PCBs).

• SMT is a popular method for assembling electronic devices due to its efficiency and cost-effectiveness.

• It involves placing electronic components directly onto the surface of a PCB, as opposed to through-hole technology where components are inserted into drilled holes.

• SMT components are typically smaller and lighter, allowi...read more

To join a system in a Windows domain, follow these steps:

• Open System Properties and click on the 'Computer Name' tab

• Click the 'Change' button and select the 'Domain' option

• Enter the name of the domain and provide domain credentials when prompted

• Restart the computer for the changes to take effect

Use the 'rmdir' command to remove an empty directory in the command line.

• Navigate to the directory you want to remove

• Use the 'rmdir' command followed by the directory name

• Confirm the deletion when prompted

The 'user lock' and 'user unlock' commands are used to lock and unlock user accounts in Linux.

• To lock a user account, use the 'usermod' command with the '-L' option followed by the username.

• Example: usermod -L username

• To unlock a user account, use the 'usermod' command with the '-U' option followed by the username.

• Example: usermod -U username

Memory allocation is the process of assigning memory to programs during runtime.

• Memory allocation is done dynamically during runtime

• It involves allocating and deallocating memory as needed

• Common methods include malloc(), calloc(), and realloc()

• Memory leaks can occur if memory is not properly deallocated

• Memory allocation is important for efficient program execution

Kernel upgrade involves several steps to ensure smooth transition and minimal downtime.

• Check system requirements and compatibility

• Download and extract the new kernel files

• Stop SAP system and backup kernel files

• Install new kernel files and adjust system parameters

• Restart SAP system and perform post-upgrade checks

To check installed softwares in Ubuntu machine, you can use the dpkg command.

• Use dpkg -l to list all installed packages

• Use dpkg -l | grep to search for specific packages

• Use dpkg -l | less to view the list page by page

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

To login to an ESXi host during lockout, use the DCUI or SSH.

• Use the Direct Console User Interface (DCUI) to login during lockout.

• Alternatively, enable SSH access and login remotely using an SSH client.

• Resetting the root password may also be necessary in some cases.

Job scheduling in operating systems involves allocating resources and prioritizing tasks.

• Job scheduling algorithms determine which tasks to execute and in what order

• Preemptive scheduling allows higher priority tasks to interrupt lower priority tasks

• Round-robin scheduling assigns a time slice to each task in a cyclic order

• Priority scheduling assigns priorities to tasks and executes higher priority tasks first

• Real-time scheduling guarantees that tasks are completed within a spe...read more

LD stands for Learning Disability.

• LD refers to a neurological disorder that affects a person's ability to learn and process information.

• It is not related to intelligence or lack of effort, but rather a difference in how the brain processes information.

• Common types of LD include dyslexia, dyscalculia, and ADHD.

• Individuals with LD may struggle with reading, writing, math, organization, and attention.

• Accommodations and support can help individuals with LD succeed in academic and...read more

OMS stands for Operations Management System, a software system used to manage and optimize business operations.

• OMS helps in planning, scheduling, and tracking of operations

• It provides real-time data and analytics for decision-making

• OMS can be used in various industries such as manufacturing, logistics, and healthcare

• Examples of OMS include SAP, Oracle, and Microsoft Dynamics

To check if your r/3 system is 32bit or 64bit, go to transaction SM51 and check the 'Architecture' column.

• Open transaction SM51

• Check the 'Architecture' column

• If it says 'x86_64', it's 64bit. If it says 'i386', it's 32bit.

Paging and Segmentation are memory management techniques used by operating systems.

• Paging divides memory into fixed-size pages and stores them in physical memory.

• Segmentation divides memory into logical segments and stores them in physical memory.

• Paging allows for efficient use of physical memory and reduces fragmentation.

• Segmentation allows for protection and sharing of memory between processes.

• Examples of operating systems that use paging and segmentation are Windows and Li...read more

A page fault occurs when a requested page is not found in the main memory. Segmentation is a memory management technique.

• Page fault: Occurs when a requested page is not present in the main memory

• Segmentation: Memory management technique that divides the memory into segments

• Examples: Page fault occurs when accessing data from virtual memory, while segmentation allows different segments for code, data, and stack

Old data can be recovered by restoring from backups or using data recovery software.

• Restore from backups taken before the OS installation

• Use data recovery software like Recuva, EaseUS Data Recovery, etc.

• Check if the data is still present in the old hard drive or partition

• If the data was synced to cloud storage, download it from there

Communication between 2 processes can be achieved through inter-process communication mechanisms.

• Use pipes to establish a unidirectional communication channel between processes

• Use sockets for bidirectional communication over a network

• Shared memory can be used to exchange data between processes

• Message queues provide a way to send and receive messages between processes

• Signals can be used to notify and communicate between processes

64bit and 32bit refer to the size of the processor registers in a computer.

• 64bit processors can handle larger amounts of memory and perform more complex calculations than 32bit processors.

• 64bit operating systems can run both 64bit and 32bit applications, while 32bit operating systems can only run 32bit applications.

• Some software may not be compatible with 64bit systems and require a 32bit version to run.

• Examples of 64bit processors include Intel Core i7 and AMD Ryzen, while e...read more

A real-time operating system is an OS that processes data and events as they occur, without delay.

• Real-time operating systems are used in applications that require immediate response, such as aviation, medical equipment, and industrial control systems.

• They prioritize tasks based on their urgency and importance, and can handle multiple tasks simultaneously.

• Examples of real-time operating systems include VxWorks, QNX, and FreeRTOS.

Deadlock avoidance schemes are strategies used to prevent the occurrence of deadlocks in a system.

• Resource allocation graph

• Banker's algorithm

• Wait-die and wound-wait schemes

• Safe state detection

To deal with a blue screen issue, start by identifying the cause and then troubleshoot accordingly.

• Check for recently installed hardware or software

• Update drivers and operating system

• Scan for malware or viruses

• Check hardware components for issues

• Perform system restore or reinstall operating system if necessary

To create a Repository file/YUM client Configuration, follow these steps:

• Create a new repository file in the /etc/yum.repos.d/ directory

• Specify the repository name, base URL, enabled status, and other options in the file

• Save the file and exit the editor

• Run 'yum clean all' command to clear the cache

• Run 'yum repolist' command to verify the repository configuration

Environment variables are dynamic values that can affect the behavior of running processes.

• Environment variables are set in the operating system or shell environment

• They are accessed by programs to retrieve information about the environment

• Examples include PATH, HOME, and USER

Windows patching is crucial for security and stability. In-place upgrade is upgrading an existing OS without losing data.

• Windows patching helps to fix security vulnerabilities and bugs in the operating system.

• It also helps to improve the stability and performance of the system.

• In-place upgrade is a process of upgrading an existing operating system to a newer version without losing any data or installed applications.

• For example, upgrading from Windows 7 to Windows 10 using the...read more

LVM (Logical Volume Manager) is configured by creating physical volumes, volume groups, and logical volumes.

• Create physical volumes using the 'pvcreate' command

• Create volume groups using the 'vgcreate' command

• Create logical volumes using the 'lvcreate' command

• Format the logical volumes with a file system using the 'mkfs' command

• Mount the logical volumes to desired mount points using the 'mount' command

• Update the '/etc/fstab' file to mount the logical volumes at boot

MBR and GPT are two different partitioning schemes used on hard drives.

• MBR stands for Master Boot Record and is limited to 2TB partition size.

• GPT stands for GUID Partition Table and supports larger partition sizes.

• MBR only allows for four primary partitions, while GPT allows for up to 128 partitions.

• GPT includes a backup partition table for redundancy.

• GPT is required for UEFI booting, while MBR is used for BIOS booting.

To control the system as a Principal, I would implement effective policies, establish clear communication channels, and foster a positive school culture.

• Implementing policies and procedures to ensure smooth operation of the school system

• Establishing clear communication channels with staff, students, and parents

• Fostering a positive school culture through collaboration, support, and recognition

• Monitoring and evaluating the system's performance regularly

• Addressing any issues or ...read more

To implement a new process, start by analyzing the current process, identifying areas for improvement, creating a plan, training employees, and monitoring progress.

• Analyze the current process to identify areas for improvement

• Create a detailed plan outlining the new process

• Communicate the changes to employees and provide necessary training

• Implement the new process gradually to minimize disruptions

• Monitor the progress and make adjustments as needed

• Seek feedback from employees a...read more

The 5 process types are continuous, batch, job shop, project, and line.

• Continuous process involves uninterrupted flow of production, like in oil refineries.

• Batch process produces a group of products at one time, like in pharmaceuticals.

• Job shop process is customized and flexible, like in machine shops.

• Project process is unique and temporary, like in construction projects.

• Line process is repetitive and standardized, like in assembly lines.

Handle the system and desktop by ensuring proper maintenance, organization, and troubleshooting.

• Regularly update software and security patches to ensure system functionality.

• Organize desktop files and folders for easy access and efficiency.

• Troubleshoot common issues such as connectivity problems or software glitches.

• Ensure proper hardware maintenance by cleaning and organizing cables and peripherals.

• Provide timely and efficient customer support for any system-related queries ...read more

Deadlock is a situation where two or more threads are blocked and waiting for each other to release resources.

• Deadlock occurs when two or more threads are waiting for each other to release resources.

• It can be resolved by using techniques like resource allocation graph, timeout, and prevention.

• Prevention can be done by avoiding circular wait, hold and wait, and no preemption.

• Example: Thread A holds resource X and waits for resource Y, while Thread B holds resource Y and waits ...read more

Multi-programming is the ability of a computer to execute multiple programs simultaneously.

• Allows for efficient use of CPU time

• Requires memory management techniques such as swapping and paging

• Examples include time-sharing systems and batch processing systems

I choose the respiratory system.

• The respiratory system is responsible for breathing and gas exchange.

• It includes the lungs, trachea, bronchi, and alveoli.

• The process of respiration involves inhaling oxygen and exhaling carbon dioxide.

• Common respiratory disorders include asthma, COPD, and pneumonia.

Yes, I have experience in installing OS and configuring network resources.

• I have experience in installing various operating systems such as Windows, Linux, and macOS.

• I am familiar with the installation process, including partitioning, formatting, and setting up boot options.

• I have configured network resources such as IP addresses, DNS servers, and network shares.

• I am proficient in using network tools such as ping, traceroute, and netstat to troubleshoot network issues.

Optimise a slow computer by cleaning up disk space, disabling unnecessary startup programs, updating drivers and software, and adding more RAM.

• Clean up disk space by deleting temporary files, uninstalling unused programs, and running disk cleanup tool

• Disable unnecessary startup programs by using Task Manager or a third-party tool like CCleaner

• Update drivers and software to the latest version to improve performance and fix bugs

• Add more RAM if possible to increase the computer'...read more

Pipe is a feature in Angular that allows transforming data before displaying it in the view.

• Pipes are used to format and filter data in Angular templates.

• They can be used to transform data types, apply currency and date formatting, and filter data based on certain criteria.

• Pipes can be chained together to perform multiple transformations on the same data.

• Custom pipes can also be created to perform specific transformations not provided by the built-in pipes.

Android architecture is a layered software stack consisting of four main layers.

• The four main layers are: Linux kernel, Libraries, Runtime, and Application framework.

• Linux kernel provides low-level hardware abstraction, memory management, and security.

• Libraries include various C/C++ libraries such as SQLite, OpenGL, and SSL.

• Runtime includes the Dalvik Virtual Machine and Android Runtime.

• Application framework provides high-level services such as Activity Manager, Content Provi...read more

PCB stands for Printed Circuit Board. It is used to mechanically support and electrically connect electronic components.

• PCBs are used in almost all electronic devices, from smartphones to computers to medical equipment.

• They are made up of layers of copper and insulating material, with a design that connects the components in a specific way.

• PCBs can be single-sided, double-sided, or multi-layered, depending on the complexity of the circuit.

• They are essential for the proper fun...read more

To troubleshoot a Mac that is not powering on, start by checking the power source and connections.

• Check if the power source is working properly

• Check if the power cable is properly connected to the Mac

• Try resetting the SMC (System Management Controller)

• Try resetting the PRAM (Parameter RAM)

• Check if there are any hardware issues such as a faulty battery or power supply

• Try booting the Mac in Safe Mode

In pharmacovigilance, a signal refers to a potential link between a drug and an adverse event.

• A signal is a piece of information that suggests a potential association between a drug and a previously unidentified adverse event.

• Signals are generated through the analysis of data from various sources, such as spontaneous reports, clinical trials, and observational studies.

• Signal detection involves identifying patterns or trends in the data that may indicate a safety concern.

• Once ...read more

I used a comprehensive risk management system that integrated various tools and techniques.

• The system was designed to identify, assess, and mitigate risks across the organization.

• It included tools such as risk registers, risk heat maps, and risk dashboards.

• The system also incorporated risk assessment methodologies such as scenario analysis and stress testing.

• Examples of risks managed included credit risk, market risk, operational risk, and reputational risk.

• Regular reporting ...read more

sed is a command-line text editor used for stream editing and manipulating text.

• sed stands for 'stream editor'

• It is used for performing text transformations on input streams or files

• sed uses regular expressions to match and modify text

• It can be used to search, replace, insert, delete, and transform text

• Example: sed 's/old/new/g' file.txt replaces all occurrences of 'old' with 'new' in file.txt

ESXi patching involves updating the ESXi hypervisor with the latest patches and updates to ensure security and stability.

• ESXi patching is essential for maintaining the security and stability of the hypervisor

• Patches are released by VMware to address vulnerabilities and bugs in the ESXi software

• Patching process involves downloading the patches, applying them to the ESXi host, and rebooting the host

• It is recommended to regularly check for and apply the latest patches to keep th...read more

Linux administration involves managing and maintaining Linux-based systems.

• Learn basic Linux commands and file system navigation

• Understand user and group management

• Configure network settings and services

• Install and update software packages

• Monitor system performance and troubleshoot issues

• Implement security measures

• Backup and restore data

• Automate tasks using shell scripting

To refresh a computer system using the keyboard, you can press the 'Ctrl' and 'R' keys simultaneously.

• Press 'Ctrl' and 'R' keys simultaneously to refresh the computer system.

• Alternatively, you can press the 'F5' key to refresh the system in some applications.

• Refreshing the system using the keyboard can help update information and clear cache.

• Make sure to save any important work before refreshing the system.

GPT and MBR are partitioning schemes used in computer storage devices to define the structure of the partition table.

• GPT stands for GUID Partition Table and is a newer partitioning scheme that allows for more partitions and larger disk sizes.

• MBR stands for Master Boot Record and is an older partitioning scheme limited to 2TB disk sizes and 4 primary partitions.

• GPT provides more flexibility and reliability compared to MBR.

• GPT is commonly used in modern computers and UEFI syste...read more

Mounting refers to the process of attaching or fixing something in a specific position, while accessories are additional items that enhance or complement the main object or system.

• Mounting involves securing or affixing an object to a surface or structure.

• Accessories are optional components that provide added functionality or aesthetic appeal.

• Mounting is typically a permanent or semi-permanent attachment, while accessories can be easily added or removed.

• Examples of mounting in...read more

Windows 7 and Windows 8 are different versions of the Microsoft operating system.

• Windows 7 was released in 2009, while Windows 8 was released in 2012.

• Windows 7 has a traditional Start menu, while Windows 8 introduced the Start screen.

• Windows 8 has a more touch-friendly interface compared to Windows 7.

• Windows 8 introduced the concept of live tiles on the Start screen.

• Windows 8 includes built-in support for USB 3.0, while Windows 7 requires additional drivers.

• Windows 8 has bett...read more

The core of an operating system is the kernel, which manages the system's resources and provides essential services.

• The kernel is responsible for managing memory, processes, and input/output operations.

• It provides services such as device drivers, file system management, and scheduling.

• Examples of operating system kernels include Linux, Windows NT, and macOS.

• The kernel acts as a bridge between applications and the hardware of the computer.

• It ensures that different processes an...read more

Event loop is a mechanism that allows for asynchronous programming by handling and executing events in a loop.

• Event loop is a part of the runtime environment that continuously checks the event queue and executes the callback functions associated with the events.

• It helps in managing non-blocking I/O operations efficiently by allowing the program to continue running while waiting for I/O operations to complete.

• Event loop is commonly used in JavaScript for handling asynchronous ...read more

To create a blank file in RHEL, you can use the 'touch' command.

• Open the terminal in RHEL.

• Use the 'touch' command followed by the desired file name to create a blank file.

• For example, to create a file named 'example.txt', you would run: touch example.txt

• The 'touch' command can also be used to update the timestamp of an existing file.

The maximum number of user accounts that can be created in Windows Server 2012 R2 depends on the edition and licensing.

• The Standard edition of Windows Server 2012 R2 supports up to 2,048 user accounts.

• The Datacenter edition of Windows Server 2012 R2 supports unlimited user accounts.

• The Essentials edition of Windows Server 2012 R2 supports up to 25 user accounts.

• The number of user accounts can also be limited by the available hardware resources and system performance.

PST and OST files are used in Microsoft Outlook to store email, contacts, and other data offline.

• PST stands for Personal Storage Table and is used for storing data in Outlook when using POP3 or IMAP email accounts.

• OST stands for Offline Storage Table and is used for storing data in Outlook when using Microsoft Exchange Server.

• PST files can be imported and exported in Outlook to backup or transfer data.

• OST files allow users to access their email and other data even when not co...read more

Diagnosing booting related issues involves checking hardware, software, and configuration settings.

• Check hardware components such as hard drive, RAM, and motherboard for any issues

• Verify that the operating system is installed correctly and up-to-date

• Check the boot order in BIOS settings

• Use diagnostic tools such as Windows Startup Repair or Linux Boot Repair

• Check for any recent software or driver updates that may have caused the issue

Deadlock is a situation where two or more processes are unable to proceed due to a circular dependency on resources.

• Deadlock occurs when two or more processes are waiting for resources held by each other.

• Conditions for deadlock are mutual exclusion, hold and wait, no preemption, and circular wait.

• Methods to prevent deadlock include resource allocation graph, banker's algorithm, and deadlock avoidance.

• To prevent deadlock in OS, use resource allocation graph and banker's algori...read more

Yes, I am familiar with OS loading.

• I have experience in installing and configuring operating systems on desktop computers.

• I am knowledgeable about the different methods of OS loading, such as using installation media or network booting.

• I am familiar with troubleshooting issues related to OS loading, such as boot errors or driver conflicts.

• I have worked with various operating systems, including Windows, macOS, and Linux.

DSCR stands for Debt Service Coverage Ratio.

• DSCR is a financial metric used to assess the ability of a company to cover its debt obligations.

• It measures the relationship between a company's operating income and its debt payments.

• A higher DSCR indicates a better ability to repay debt.

• DSCR is calculated by dividing the company's net operating income by its total debt service.

• For example, if a company has a net operating income of $500,000 and total debt service of $400,000, the...read more

Managing computing priorities involves prioritizing requests based on urgency, importance, and available resources.

• Assess the urgency and importance of each request

• Consider the impact on business goals and objectives

• Evaluate the available resources and capacity

• Communicate with stakeholders to understand their needs

• Establish a prioritization framework or criteria

• Regularly review and adjust priorities as needed

AD FSMO roles are the 5 special roles in Active Directory that are responsible for managing various aspects of the domain.

• There are 5 FSMO roles: Schema Master, Domain Naming Master, RID Master, PDC Emulator, and Infrastructure Master.

• Schema Master: responsible for making changes to the Active Directory schema.

• Domain Naming Master: responsible for adding or removing domains in the forest.

• RID Master: responsible for allocating RIDs (Relative Identifiers) to domain controllers....read more

IPC stands for Inter-Process Communication. It is a mechanism that allows processes to communicate and synchronize with each other.

• IPC allows processes to share data and communicate with each other

• There are different types of IPC mechanisms such as pipes, message queues, shared memory, and sockets

• Working principal involves sending and receiving messages between processes

• Example: Using pipes to communicate between a parent process and a child process

Thread life cycle refers to the various stages a thread goes through during its execution.

• Thread is created

• Thread is started

• Thread is running

• Thread is blocked

• Thread is terminated

To recover root password, boot into single-user mode and reset the password.

• Reboot the system and press 'e' at the GRUB menu to edit the boot options.

• Add 'single' or 'init=/bin/bash' to the end of the 'linux' line and press F10 to boot.

• Run 'passwd' command to reset the root password.

• Reboot the system and login with the new password.

Active Directory can be installed using the Server Manager or PowerShell.

• Open Server Manager and select Add Roles and Features

• Select Active Directory Domain Services and follow the wizard

• Alternatively, use PowerShell command Install-WindowsFeature AD-Domain-Services

• Configure the domain and add users and groups as needed

A scheduler is a function that manages the execution of tasks or processes.

• Inputs: tasks or processes to be scheduled, priority or order of execution

• Output: schedule or order in which tasks or processes will be executed

• Functioning: determines the order of execution based on predefined criteria or algorithms

To create a user account in AD, follow these steps:

• Open Active Directory Users and Computers

• Right-click on the domain and select 'New' and then 'User'

• Enter the user's information, such as name and password

• Click 'Next' and then 'Finish' to create the account

An inode is a data structure used to store information about a file or directory in AIX.

• Inodes contain metadata such as file size, ownership, permissions, and timestamps.

• Each file or directory in AIX has a unique inode number.

• Inodes are used by the file system to locate and access files on disk.

• The number of inodes available on a file system is determined at the time of file system creation.

• Inodes can become fragmented over time, leading to decreased performance.

• The command '...read more

A buffer is a solution that resists changes in pH when small amounts of acid or base are added to it.

• Buffers are made up of a weak acid and its conjugate base or a weak base and its conjugate acid

• They are used to maintain a stable pH in various chemical and biological processes

• Examples of buffers include phosphate buffer, Tris buffer, and acetate buffer

Build in JCL is a job control language statement used to compile and link programs in mainframe environments.

• Build statement is used to compile and link programs in JCL.

• It specifies the program to be compiled and linked, as well as any necessary parameters.

• Example: //BUILD EXEC PGM=IEBGENER,PARM='INPUT=SYSUT1,OUTPUT=SYSUT2'

A system call is a request made by a program to the operating system for a service or resource.

• A program executes a system call instruction.

• The CPU switches to kernel mode and transfers control to the operating system.

• The operating system performs the requested service or provides the requested resource.

• The operating system returns control to the program by switching back to user mode.

• Examples of system calls include open(), read(), write(), and close().

Multitasking is executing multiple tasks simultaneously while multithreading is executing multiple threads within a single process.

• Multitasking involves running multiple processes at the same time while multithreading involves running multiple threads within a single process.

• Multitasking requires more resources than multithreading.

• Multithreading is more efficient than multitasking as it reduces the overhead of context switching.

• Examples of multitasking include running multipl...read more

DEP provides security by preventing execution of malicious code in memory.

• DEP stands for Data Execution Prevention.

• It is a security feature in modern operating systems.

• DEP prevents execution of code in memory regions marked as non-executable.

• This helps prevent buffer overflow attacks and other types of malware.

• DEP can be enabled for specific applications or for the entire system.

• Examples of DEP-enabled applications include Microsoft Office and Internet Explorer.

To check running processes and disk space, use commands like ps, top, df, and du.

• Use 'ps' command to display currently running processes

• Use 'top' command to display real-time system information, including processes

• Use 'df' command to check disk space usage on filesystems

• Use 'du' command to check disk usage of directories

A drive is a device or mechanism used to store and retrieve data or information.

• Drives can be physical devices like hard disk drives (HDD) or solid-state drives (SSD).

• They can also be virtual drives created by software, such as network drives or cloud storage.

• Drives are used to store various types of data, including files, documents, programs, and operating systems.

• Examples of drives include C: drive, D: drive, USB drives, and DVD drives.

Yes, I have knowledge of Linux server.

• I have experience in managing and configuring Linux servers.

• I am familiar with command-line interface and shell scripting.

• I have worked with various Linux distributions such as Ubuntu, CentOS, and Debian.

• I have set up and maintained web servers, database servers, and file servers on Linux.

• I have knowledge of Linux security and network configuration.

sed command is a stream editor for filtering and transforming text, while find command is used to search for files in a directory hierarchy.

• sed command is used to perform text transformations on an input stream or file

• find command is used to search for files in a directory hierarchy based on various criteria

• sed command can be used to replace text, delete lines, or perform other text manipulations

• find command can search for files based on name, size, permissions, and other att...read more

FreeRTOS uses priority-based preemptive scheduling with round-robin time slicing.

• Tasks are assigned priorities and the scheduler always runs the highest priority task that is ready to run.

• Preemption occurs when a higher priority task becomes ready to run.

• Round-robin time slicing ensures that tasks with the same priority get equal CPU time.

• FreeRTOS also supports co-operative scheduling where tasks yield control to other tasks voluntarily.

• The scheduler is implemented as a part ...read more

Semaphore is a signaling mechanism to control access to a shared resource, while Mutex is a locking mechanism to ensure only one thread accesses a resource at a time.

• Semaphore can allow multiple threads to access a shared resource simultaneously, while Mutex ensures only one thread can access the resource at a time.

• Mutex is more restrictive than Semaphore as it provides exclusive access to a resource, while Semaphore can be used to control access to a pool of resources.

• Exampl...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

Linux command is a text-based interface used to interact with the operating system.

• Linux commands are case-sensitive

• Commands are typically entered in the terminal

• Commands are used to perform various tasks like file management, system administration, networking, etc.

• Examples: ls (list files in a directory), cd (change directory), mkdir (make directory)

umask value determines default file permissions when creating a file or directory

• umask is a 3-digit octal value that subtracts from the maximum permission value (777 for files, 666 for directories)

• default umask value for users is 022 (files: 644, directories: 755)

• default umask value for root is 002 (files: 664, directories: 775)

The latest OS on MAC is macOS Big Sur.

• macOS Big Sur is the 17th major release of macOS.

• It was announced at Apple's Worldwide Developers Conference in June 2020.

• macOS Big Sur introduces a redesigned user interface and various new features.

• Some notable features include a new Control Center, updated Safari browser, and improved Messages app.

• It also brings support for Apple Silicon, allowing Macs to run on Apple's own processors.

When a parent process is terminated, the child process becomes an orphan and is adopted by the init process.

• When a parent process is terminated, the child process is not automatically terminated.

• The child process becomes an orphan and is adopted by the init process.

• The init process becomes the new parent of the orphaned child process.

• The orphaned child process continues to run independently until it completes or is terminated.

Producer-consumer problem involves synchronization between threads to avoid race conditions.

• Producer produces data and adds it to a shared buffer

• Consumer consumes data from the shared buffer

• Synchronization is required to avoid race conditions

• Code example: https://www.geeksforgeeks.org/producer-consumer-solution-using-threads-in-java/

Interrupt handling is a mechanism to handle asynchronous events in real-time systems.

• Interrupts are signals generated by hardware or software to interrupt the normal execution of a program.

• Interrupts are prioritized and handled by the Interrupt Service Routine (ISR).

• ISR saves the current state of the processor, executes the interrupt handler code, and restores the saved state.

• Interrupts can be edge-triggered or level-triggered, and can be handled synchronously or asynchronous...read more

I have a strong understanding of Linux Kernel and its subsystems.

• I have experience working with various subsystems such as memory management, process management, file systems, and networking.

• I am familiar with kernel debugging techniques and tools such as GDB and KDB.

• I have contributed to the Linux Kernel community through bug fixes and feature enhancements.

• I keep myself updated with the latest developments in the Linux Kernel and its subsystems through various online resourc...read more

TOP and PS are commands used in Unix-like operating systems to display information about running processes. TOP is called TOP because it shows the top processes consuming system resources.

• TOP is an interactive command that continuously updates the process list, while PS displays a snapshot of the current processes.

• TOP provides real-time information about CPU usage, memory usage, and other system statistics, while PS provides a static view of the processes.

• TOP allows users to ...read more

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).

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

Windows Firewall is a network security system that monitors and controls incoming and outgoing network traffic. Windows Defender is an antivirus software that protects against malware and other threats.

• Windows Firewall controls network traffic while Windows Defender protects against malware

• Windows Firewall is a network security system while Windows Defender is an antivirus software

• Windows Firewall is built-in to Windows while Windows Defender needs to be installed separately

• W...read more