What is an operating system?

• Answer: An operating system is software that manages hardware resources and provides services for computer programs.

What is the difference between kernel and user mode?

• Answer: Kernel mode has full access to hardware, while user mode has restricted access for running applications.

What are processes and threads?

• Answer: A process is an executing instance of a program, while a thread is the smallest unit of execution within a process.

What is multitasking?

• Answer: Multitasking is the ability of an OS to execute multiple processes or threads concurrently.

What is a deadlock?

• Answer: A deadlock occurs when two or more processes are blocked, waiting for each other to release resources, causing them to remain stuck indefinitely.

What are the different types of scheduling algorithms?

• Answer: Common scheduling algorithms include First-Come, First-Served (FCFS), Round Robin (RR), Shortest Job First (SJF), and Priority Scheduling.

What is virtual memory?

• Answer: Virtual memory allows the OS to use disk storage as additional memory, enabling programs to run even if physical RAM is full.

What is a page fault?

• Answer: A page fault occurs when a program tries to access data not currently in memory, requiring the OS to load it from disk.

What is the difference between a process and a thread?

• Answer: A process is an independent program with its own memory space, while a thread is a unit of execution within a process.

What is a semaphore?

• Answer: A semaphore is a synchronization mechanism used to control access to a shared resource by multiple processes.

What is a system call?

• Answer: A system call is a request made by a program to the OS to perform an operation that the program cannot do directly.

What is a file system?

• Answer: A file system is a way of organizing and storing files on a disk, enabling efficient data access and management.

What is a deadlock prevention strategy?

• Answer: Deadlock prevention involves ensuring that at least one of the necessary conditions for a deadlock cannot occur, such as by avoiding circular wait conditions.

What is context switching?

• Answer: Context switching is the process of saving the state of a running process and restoring the state of a different process to enable multitasking.

What is a race condition?

• Answer: A race condition occurs when multiple processes or threads access shared resources simultaneously, leading to unpredictable results.

What is the difference between hard and soft real-time systems?

• Answer: Hard real-time systems require strict deadlines, while soft real-time systems allow some flexibility in meeting deadlines.

What are the different types of operating systems?

• Answer: Types include batch OS, time-sharing OS, distributed OS, real-time OS, and network OS.

What is a file descriptor?

• Answer: A file descriptor is an integer handle used by the OS to identify and manage open files.

What is the difference between a monolithic kernel and a microkernel?

• Answer: A monolithic kernel runs all OS services in kernel space, while a microkernel runs only basic services, with other services running in user space.

What is paging in an OS?

• Answer: Paging is a memory management scheme that divides physical memory into fixed-sized blocks called pages, allowing non-contiguous memory allocation.

What is a process control block (PCB)?

• Answer: A PCB is a data structure that contains information about a process, such as its state, program counter, and memory pointers.

What is swapping in an OS?

• Answer: Swapping is the process of moving data between physical memory and secondary storage to free up memory space for other processes.

What is a fork system call?

• Answer: The fork system call creates a new process by duplicating the calling process.

What is the difference between a mutex and a semaphore?

• Answer: A mutex is used to provide mutual exclusion, ensuring only one process can access a resource at a time, while a semaphore is a signaling mechanism for managing resource access.

What is the role of an interrupt in an operating system?

• Answer: Interrupts allow the OS to immediately handle high-priority tasks, pausing ongoing operations and resuming them after handling the interrupt.

What is the difference between a hard link and a symbolic link?

• Answer: A hard link points directly to the data on disk, while a symbolic link is a reference to another file.

What is a shell in the context of an operating system?

• Answer: A shell is a command-line interface that allows users to interact with the operating system by typing commands.

What is a system process?

• Answer: A system process is a background process that is essential for the operating system's functions, such as managing hardware resources.

What is thrashing?

• Answer: Thrashing occurs when the OS spends more time swapping data between memory and disk than executing actual processes, severely degrading system performance.

What are threads and how are they different from processes?

• Answer: Threads are smaller units of execution within a process, sharing the same memory space, while processes are independent programs with their own memory.