Questions: Operating Systems

Question 51: What is aging in operating systems scheduling?

A Removing old files from the system automatically
B Gradually increasing the priority of processes that wait for a long time to prevent starvation
C Recycling physical RAM sticks after years of usage
D Reducing CPU frequency to save battery life over time

Explanation: Aging is a technique of gradually increasing the priority of processes that wait in the system for a long time to prevent starvation.

Question 52: What is the primary function of a device driver?

A To translate operating system commands into hardware-specific operations for a device
B To connect the computer to wireless internet access points
C To supply electrical power to hardware components
D To act as a graphical user interface for applications

Explanation: A device driver is a specific program that controls or operates a particular device attached to a computer, providing an interface to the OS.

Question 53: Which of the following is a synchronization mechanism that can be implemented in hardware?

A Test-and-Set instruction
B Message passing queues
C Paging tables
D Inode structures

Explanation: Test-and-Set and Compare-and-Swap are atomic hardware instructions used to implement mutual exclusion and semaphores.

Question 54: What is a monolithic kernel?

A A kernel where all operating system services run in kernel space as a single large program
B A minimal kernel containing only process scheduling and memory management
C A cloud-based kernel running on distributed virtual servers
D An embedded kernel stored entirely in read-only ROM

Explanation: A monolithic kernel is an operating system architecture where the entire operating system works in kernel space and runs in a single address space.

Question 55: What is a real-time operating system (RTOS)?

A An OS that guarantees processing data within strict, fixed time constraints
B An OS used exclusively for high-end graphic rendering and gaming
C An OS that tracks physical time zone changes globally
D An OS with no concept of multitasking or scheduling

Explanation: An RTOS is an operating system intended to serve real-time applications that process data as it comes in with strict timing constraints.

Question 56: What is the function of the Translation Lookaside Buffer (TLB)?

A To store recently used virtual-to-physical address translations for fast lookup
B To buffer network packets before sending them over Ethernet
C To keep track of open files and directory pointers
D To store user login credentials securely

Explanation: The TLB is a special fast-lookup hardware cache used to speed up virtual-to-physical address translation.

Question 57: Which storage placement strategy allocates the smallest hole that is big enough to satisfy a memory request?

A First-fit
B Best-fit
C Worst-fit
D Next-fit

Explanation: Best-fit allocates the smallest hole from the list of available free holes that is large enough.

Question 58: What is dynamic loading?

A Loading routines into memory only when they are actually called
B Swapping entire memory partitions to disk during runtime
C Updating device driver software automatically over the internet
D Allocating virtual memory pages dynamically on demand

Explanation: Dynamic loading is a routine loaded into memory only when it is called, improving memory space utilization.

Question 59: What is dynamic linking?

A Linking system libraries to the executable only at execution time
B Binding memory addresses during compile time
C Connecting network sockets dynamically between clients
D Merging multiple source code files into a single object file

Explanation: Dynamic linking postpones the linking of library routines until execution time, reducing executable file size.

Question 60: Which of the following describes mutual exclusion?

A Only one process can execute in its critical section at a time
B All processes can access shared resources simultaneously
C Processes must share CPU time equally without priority
D Two processes can never execute on separate CPU cores

Explanation: Mutual exclusion ensures that if one process is executing in its critical section, no other processes can execute in their critical sections.

Question 61: What is a bootstrap program?

A A program stored in ROM that initializes hardware and loads the OS kernel
B An application used to format hard drives during installation
C A user-mode utility that manages desktop themes
D A network tool used to test connection speeds

Explanation: The bootstrap program is stored in ROM or EPROM and initializes hardware, loads the kernel, and starts the OS.

Question 62: What is an interrupt?

A A signal to the processor indicating an event that requires immediate attention
B An error that permanently damages the CPU arithmetic unit
C A command that shuts down the operating system safely
D A pause in user keyboard input due to inactivity

Explanation: An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention.

Question 63: What is direct memory access (DMA)?

A A feature allowing devices to transfer data directly to/from memory without CPU intervention
B A method for programs to bypass security checks and access RAM directly
C The physical wiring connecting the CPU to the RAM slots
D A technique for expanding virtual memory using flash drives

Explanation: DMA allows hardware subsystems to access main system memory independently of the central processing unit.

Question 64: Which scheduler selects processes from the ready queue and allocates the CPU to one of them?

A Short-term scheduler (CPU scheduler)
B Long-term scheduler (job scheduler)
C Medium-term scheduler (swapper)
D I/O scheduler

Explanation: The short-term scheduler (or CPU scheduler) selects which process should be executed next and allocates CPU time.

Question 65: What is the primary role of the long-term scheduler?

A To select processes from job storage and load them into memory
B To allocate CPU time slices every few milliseconds
C To manage virtual memory page swaps to disk
D To control peripheral device drivers during startup

Explanation: The long-term scheduler (job scheduler) selects processes from a pool and loads them into memory for execution.

Question 66: What does a medium-term scheduler do?

A Swaps processes between main memory and secondary storage
B Decides which thread runs on which CPU core
C Manages network socket connections over time
D Schedules disk track head movements

Explanation: The medium-term scheduler removes processes from memory (swapping) to reduce the degree of multiprogramming and later re-introduces them.

Question 67: What is a zombie process?

A A process that has finished execution but still has an entry in the process table
B A malicious malware process hidden inside system files
C A process stuck in an infinite loop consuming 100% CPU
D A process that refuses to terminate when killed by the user

Explanation: A zombie process is a process that has completed execution but still has an entry in the process table, usually because its parent has not yet read its exit status.

Question 68: What is an orphan process?

A A child process whose parent process has terminated
B A process running without any memory allocation
C A file that is no longer linked to any directory
D A thread whose parent process crashed unexpectedly

Explanation: An orphan process is a child process whose parent process has finished or terminated, leaving it to be adopted by the init process.

Question 69: Which of the following is an example of inter-process communication (IPC)?

A Shared memory and message passing
B Paging and segmentation
C Compilation and linking
D Caching and buffering

Explanation: Shared memory and message passing are standard mechanisms for inter-process communication.

Question 70: What is a critical section?

A A code segment that accesses shared resources prone to race conditions
B The boot sequence code executed when the PC starts
C A section of the kernel responsible for handling hardware errors
D Encrypted memory reserved for security credentials

Explanation: A critical section is a piece of code that accesses shared variables or resources that can lead to race conditions if executed concurrently.

Question 71: What is a monitor in concurrency?

A A synchronization construct providing mutual exclusion and conditional waiting
B A hardware display screen controller driver
C A diagnostic tool for monitoring CPU temperature and voltage
D A logging daemon that records system error messages

Explanation: A monitor is a synchronization construct that allows threads to have both mutual exclusion and the ability to wait for certain conditions.

Question 72: What is spinlock?

A A lock where a thread waits in a loop repeatedly checking if it becomes available
B A mechanism that locks hard drive platters during sudden physical movement
C A security feature that locks user accounts after failed login attempts
D A process scheduling queue that cycles in a round-robin order

Explanation: A spinlock is a lock where a thread trying to acquire it simply waits in a loop ("spin") while repeatedly checking if the lock is available.

Question 73: What is priority inversion?

A When a high-priority process is indirectly blocked by a low-priority process holding a resource
B When background tasks run faster than foreground applications
C When the operating system reverses process priorities randomly
D When a user manually lowers the priority of system services

Explanation: Priority inversion occurs when a high-priority process is indirectly preempted by a lower-priority process holding a required resource.

Question 74: Which page replacement algorithm replaces the page that will not be used for the longest time in the future?

A Optimal page replacement algorithm
B Least Recently Used (LRU)
C First-In, First-Out (FIFO)
D Clock page replacement

Explanation: The Optimal page replacement algorithm looks forward in time and replaces the page that won't be needed for the longest time.

Question 75: What is the primary purpose of hierarchical paging?

A To break down large page tables so they do not need to be contiguous in memory
B To speed up disk read and write speeds for large files
C To prioritize high-priority tasks over background processes
D To encrypt virtual memory pages against unauthorized access

Explanation: Hierarchical paging breaks the page table into smaller pieces to avoid keeping an entire large page table contiguous in memory.

Question 76: What is an inverted page table?

A A page table structure with one entry per physical frame instead of per virtual address
B A table that stores physical addresses in reverse numerical order
C A directory structure used exclusively for inverted file systems
D A backup table used when the primary page table becomes corrupted

Explanation: An inverted page table has one entry for each real page frame of memory, saving significant memory space.

Question 77: What is segmentation in memory management?

A Dividing memory into logical variable-sized segments like code, data, and stack
B Splitting hard drive storage into equal sectors and tracks
C Dividing CPU time slices among active user threads
D Separating network traffic into individual TCP packets

Explanation: Segmentation is a memory management scheme that divides memory into logical variable-sized segments like code, data, and stack.

Question 78: What is the main advantage of user-level threads over kernel-level threads?

A Thread management and switching can be done fast without kernel intervention
B They can run on multiple CPU cores simultaneously without OS support
C The kernel automatically handles all scheduling without library overhead
D They have direct access to physical hardware registers

Explanation: User-level threads are managed by user-space libraries, allowing fast creation and switching without kernel intervention.

Question 79: What is a file descriptor?

A An integer handle used by a process to identify and access an open file
B A text metadata string describing the creation date of a file
C The physical sector address where file data begins on disk
D An encryption key used to protect private user documents

Explanation: A file descriptor is an abstract integer handle used by a process to identify and access an open file.

Question 80: What is an inode in UNIX file systems?

A A data structure storing file metadata and block pointers, excluding filename and content
B The root directory folder that contains all other system files
C An input node used for managing keyboard and mouse interrupts
D A network socket identifier used for remote file mounting

Explanation: An inode is a data structure that stores metadata about a file, excluding its filename and content.

Question 81: What is a hard link in a file system?

A A directory entry that points directly to the same underlying inode as another filename
B A shortcut pointer file that redirects to a different directory path
C A physical connection cable linking two separate hard drives
D A read-only backup copy stored on secondary storage

Explanation: A hard link points directly to the inode of a file, allowing multiple directory entries to reference the same inode.

Question 82: What is a symbolic link (soft link)?

A A file containing a path reference to another file or directory
B A direct pointer to an inode sharing the exact same file blocks
C A virtual file created dynamically by the kernel in RAM
D A compressed archive containing multiple backup files

Explanation: A symbolic link contains a reference path to another file or directory.

Question 83: Which disk scheduling algorithm selects the request closest to the current head position?

A Shortest Seek Time First (SSTF)
B First-Come, First-Served (FCFS)
C C-SCAN
D FIFO

Explanation: Shortest Seek Time First (SSTF) selects the disk request that requires the minimum head movement from the current position.

Question 84: What is C-SCAN (Circular SCAN) disk scheduling?

A A variation of SCAN that services requests in only one direction, returning immediately to the beginning
B A scheduling method that reverses direction every time a single request is completed
C A random disk access algorithm designed for solid-state drives
D An algorithm that prioritizes inner tracks over outer tracks exclusively

Explanation: C-SCAN services requests in one direction and immediately returns to the beginning without servicing requests on the return trip.

Question 85: What is write-through caching in file systems?

A Data is written into the cache and immediately written to disk as well
B Data is written only to cache and delayed until disk flush
C Data bypasses cache entirely and goes straight to disk sectors
D Data is written directly to secondary tape backups

Explanation: Write-through updates data in cache and simultaneously writes it to disk storage to maintain data integrity.

Question 86: What is write-back (write-deferred) caching?

A Modifications are written to cache first and delayed until cache blocks are replaced
B Modifications are written to disk immediately and cached afterwards
C Writing is disabled until the system encounters a low memory warning
D Data is mirrored across two physical disks simultaneously

Explanation: Write-back caching writes modifications to cache first, delaying disk writes until cache blocks are replaced.

Question 87: What is an access control matrix in operating system security?

A A table defining permissions of subjects over objects in the system
B A matrix used for calculating virtual-to-physical memory addresses
C A scheduling queue priority assignment table
D A network firewall routing rule table

Explanation: An access control matrix defines permissions of subjects over objects in the system.

Question 88: What is a capability list in file and resource protection?

A A list associated with a domain specifying authorized objects and permissions
B A list of hardware instructions supported by the CPU architecture
C A list of running processes eligible for CPU scheduling
D A registry of installed device drivers

Explanation: A capability list is associated with a domain specifying authorized objects and permissions.

Question 89: What is a hypervisor?

A Software or firmware that creates and runs virtual machines
B A high-speed network router connecting data center servers
C A tool that monitors CPU clock speeds and temperatures
D An advanced file system manager for RAID arrays

Explanation: A hypervisor is software, firmware, or hardware that creates and runs virtual machines.

Question 90: What is the main difference between Type 1 and Type 2 hypervisors?

A Type 1 runs on bare metal hardware, while Type 2 runs on a host operating system
B Type 1 supports Windows only, while Type 2 supports Linux only
C Type 1 is software-based, while Type 2 is strictly hardware-based
D Type 1 handles memory virtualization, while Type 2 handles I/O virtualization

Explanation: Type 1 hypervisors run directly on bare metal hardware, while Type 2 run on top of an existing host OS.

Question 91: What is symmetric multiprocessing (SMP)?

A An architecture where multiple identical processors share main memory and run the OS concurrently
B A system where one master processor controls all slave processors
C A network of independent computers sharing workload over Ethernet
D A single processor executing multiple threads using hyper-threading

Explanation: In SMP, multiple processors share main memory and run the OS concurrently with equal access.

Question 92: What is asymmetric multiprocessing?

A An architecture where a master processor assigns tasks to slave processors
B An architecture where all processors have equal access to all resources
C A technique where CPU cores dynamically adjust voltage based on workload
D Running different operating systems on separate partitions

Explanation: In asymmetric multiprocessing, a master processor manages and assigns tasks to slave processors.

Question 93: What is a bootstrap loader?

A A small program that locates and loads the main OS kernel into memory
B A tool that boots up connected USB peripheral devices
C An application loader that starts user desktop programs
D A network utility that downloads system updates

Explanation: The bootstrap loader is a small program responsible for locating and loading the OS kernel into memory.

Question 94: What is the purpose of the ready queue?

A To hold processes that are ready and waiting for CPU execution time
B To store processes currently waiting for I/O completion
C To keep track of terminated processes before cleanup
D To buffer files before they are written to disk

Explanation: The ready queue holds all processes that are ready and waiting to execute on the CPU.

Question 95: What is a device queue?

A A queue of processes waiting for a specific I/O device
B A list of hardware devices installed in the device manager
C A buffer for storing network packets before routing
D A queue of print jobs waiting in the spooler

Explanation: A device queue holds processes waiting for a specific I/O device.

Question 96: What is multiprogramming?

A Holding multiple programs in main memory to increase CPU utilization
B Writing code in multiple programming languages simultaneously
C Running multiple operating systems inside virtual machines
D Compiling source files using parallel compiler threads

Explanation: Multiprogramming keeps multiple programs in main memory so the CPU always has something to execute.

Question 97: What is the degree of multiprogramming?

A The number of processes residing in main memory at one time
B The number of CPU cores active in the system
C The total capacity of installed RAM in gigabytes
D The number of user accounts configured on the machine

Explanation: The degree of multiprogramming refers to the number of processes in main memory at a given time.

Question 98: What is CPU utilization?

A The percentage of time the processor is busy executing instructions
B The speed at which the CPU clock ticks per second
C The amount of electric power consumed by the CPU core
D The ratio of cache memory hits to misses

Explanation: CPU utilization measures the percentage of time the CPU is actively executing instructions.

Question 99: What is throughput in CPU scheduling?

A The number of processes completed per time unit
B The total amount of memory allocated to all running jobs
C The data transfer rate of the hard disk controller
D The response time of interactive user commands

Explanation: Throughput is the number of processes completed per unit of time.

Question 100: What is waiting time in CPU scheduling?

A The total time a process spends waiting in the ready queue
B The time taken to load a program from disk into RAM
C The duration of an I/O request operation
D The time elapsed between user login and desktop load

Explanation: Waiting time is the total amount of time a process spends waiting in the ready queue.

Quiz: Operating Systems

Operating Systems

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