Operating System Subcategories

Memory Management Swapping 1	Process Scheduling Queue
Virtual Memory Page Replacement Algorithms 1	Linux
Cpu Scheduling	Memory Management
Computer Fundamentals	Cpu Scheduling Benefits
Threads Signal Handling	Threads Ult Klt
Distributed Operating System	Basics
Operating System	Processes
Cpu Scheduling Algorithms 1	Cpu Scheduling Algorithms 2
Deadlock	Deadlock Avoidance
Memory Management Swapping 2	Memory Allocation 1
Secondary Storage	Memory Management Paging 1
Memory Management Paging 2	Rtos
Multimedia System Cpu Disk Scheduling	Security Intrusion Detection
Virtual Memory Thrashing	File System Interface Access Methods 1
File System Interface Directory Structure 1	File System Interface Directory Structure 2
File System Interface Mounting Sharing	File System Allocation Methods 1
Disk Scheduling 2	Disk Management
Classic Sync Problems	Semaphores 1
Process Creation	Multimedia System Network Management
Semaphores 2	Cpu Scheduling 2
Application Io Interface 1	Inter Process Communication
Process Synchronization	Multimedia System Compression 1
Network File System 1	Disk Scheduling 1
Mass Storage Raid 1	File System 1
Communication Systems Bandwidth Transmission Medium	Security Cryptography
Two Port Network	Process Rpc
Virtual Memory Page Replacement Algorithms 2	Virtual Memory Frame Allocation
Network File System 2	File System Allocation Methods 2
File System Allocation Methods 3	Process Control Block
Process Structures	Critical Section Problem
Process Sync Monitors	Atomic Transactions
Deadlock Recovery	Memory Allocation 2
Memory Management Segmentation	Application Io Interface 2
Kernel Io Subsystems	Multimedia System Compression 2
Multimedia System Compression 3	Security User Authentication
Security Program System Threats	Security System Facility
Threads Fork Exec	Threads Cancellation
Threads Pools	Multi Threading Models
Virtual Memory Demand Paging	Virtual Memory
File System Concepts	File System Implementation
File System Interface Access Methods 2	File System Recovery
Io Subsystem	Swap Space Management
Mass Storage Raid 2	Mass Storage Tertiary Storage
Protection Concepts	Protection Access Matrix
Security	Protection Memory Protection
Protection Revocation Access Rights	Network Structure Topology
Robustness	Distributed File System
Distributed Synchronization	Deadlock Prevention
Deadlock Detection	Threads
File System Interface Protection	File System Free Space Performance

What will happen if a non-recursive mutex is locked more than once?

A. Starvation
B. Deadlock
C. Aging
D. Signaling

Explanation: If a thread which had already locked a mutex, tries to lock the mutex again, it will enter into the waiting list of that mutex, which results in a deadlock. It is because no other thread can unlock the mutex.

What is a semaphore?

A. Is a binary mutex
B. Must be accessed from only one process
C. Can be accessed from multiple processes
D. None of the mentioned

What are the two kinds of semaphores?

A. Mutex & counting
B. Binary & counting
C. Counting & decimal
D. Decimal & binary

What is a mutex?

A. Is a binary mutex
B. Must be accessed from only one process
C. Can be accessed from multiple processes
D. None of the mentioned

Explanation: میوٹیکس (Mutex) کیا ہے؟ میوٹیکس (جس کا پورا نام Mutual Exclusion ہے) آپریٹنگ سسٹم میں ایک ایسا تالا (Lock) ہے جو یہ یقینی بناتا ہے کہ کمپیوٹر کا کوئی بھی خاص حصہ یا ڈیٹا (Shared Resource) ایک وقت میں صرف ایک ہی پروگرام یا تھریڈ (Thread) استعمال کرے۔

At a particular time of computation the value of a counting semaphore is 7.Then 20 P operations and 15 V operations were completed on this semaphore. The resulting value of the semaphore is? (GATE 1987)

A. 42
B. 2
C. 7
D. 12

Explanation: P represents Wait and V represents Signal. P operation will decrease the value by 1 every time and V operation will increase the value by 1 every time. In semaphore operations:P Operation (Wait/Down): Decrements the value of the semaphore ($S = S - 1$).V Operation (Signal/Up): Increments the value of the semaphore ($S = S + 1$).Step-by-step:Initial Value: $7$After 20 P operations: $7 - 20 = -13$After 15 V operations: $-13 + 15 = 2$

A binary semaphore is a semaphore with integer values ____________

A. 1
B. -1
C. 0.8
D. 0.5

The following pair of processes share a common variable X. Process A int Y; A1: Y = X*2; A2: X = Y; Process B int Z; B1: Z = X+1; B2: X = Z; X is set to 5 before either process begins execution. As usual, statements within a process are executed sequentially, but statements in process A may execute in any order with respect to statements in process B. How many different values of X are possible after both processes finish executing?

A. Two
B. Three
C. Four
D. Eight

Explanation: Here are the possible ways in which statements from A and B can be interleaved. A1 A2 B1 B2: X = 11 A1 B1 A2 B2: X = 6 A1 B1 B2 A2: X = 10 B1 A1 B2 A2: X = 10 B1 A1 A2 B2: X = 6 B1 B2 A1 A2: X = 12.

The program follows to use a shared binary semaphore T. Process A int Y; A1: Y = X*2; A2: X = Y; signal(T); Process B int Z; B1: wait(T); B2: Z = X+1; X = Z; T is set to 0 before either process begins execution and, as before, X is set to 5. Now, how many different values of X are possible after both processes finish executing?

A. One
B. Two
C. Three
D. Four

Explanation: The semaphore T ensures that all the statements from A finish execution before B begins. So now there is only one way in which statements from A and B can be interleaved: A1 A2 B1 B2: X = 11.

Semaphores are mostly used to implement ____________

A. System calls
B. Ipc mechanisms
C. System protection
D. None of the mentioned

Spinlocks are intended to provide __________ only.

A. Mutual exclusion
B. Bounded waiting
C. Aging
D. Progress

Explanation: A spinlock is a mutual exclusion mechanism that uses busy-waiting (looping) instead of sleeping, making it ideal for very short critical sections in multi-core systems.