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Operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Q.21 Which of the following operating systems is generally considered the safest/most secure in a server environment?
LINUX
UNIX
Windows
None
Explanation
UNIX and Linux-based systems are often cited for their robust security models and permission structures compared to early consumer versions of Windows.
Q.22 Which diagram is specifically used to detect and represent deadlocks in an operating system?
Resource allocation graph
Gantt chart
Algorithm
None
Explanation
A Resource Allocation Graph (RAG) tracks which processes hold which resources and which ones they are waiting for, helping identify circular wait conditions.
Q.23 Which of the following is NOT a primary function of an operating system?
Process management
Disk management
Language management
None
Explanation
Operating systems manage hardware and processes, but language management (translation) is typically the job of compilers and interpreters.
Q.24 What is the state of a process when it is waiting for some event (like I/O completion) to occur?
New
Ready
Wait
None
Explanation
The ‘Wait’ or ‘Blocked’ state is where a process resides when it cannot execute until a specific event or resource becomes available.
Q.25 What is the full form of the LRU page replacement algorithm?
Lest recently used
Least recently used
Low read used
None
Explanation
LRU stands for Least Recently Used; it replaces the page that has not been accessed for the longest period of time.
Q.26 What is the condition where only one process can execute in its critical section at any given time?
Mutual exclusion
Critical section
Synchronous
None
Explanation
Mutual Exclusion (Mutex) ensures that shared resources are accessed by only one process at a time to prevent data corruption.
Q.27 In which CPU scheduling algorithm is a 'Time Quantum' specifically defined?
SJF (Shortest Job First)
RR (Round Robin)
Priority Scheduling
None
Explanation
Round Robin (RR) scheduling assigns a fixed time unit called a quantum to each process in the ready queue.
Q.28 In the context of memory management, a program always deals with which type of address?
Logical address
Absolute address
Physical address
None
Explanation
Programs generate logical addresses (virtual addresses), which the Memory Management Unit (MMU) then maps to physical addresses in RAM.
Q.29 Which of the following is considered a classical synchronization problem in OS?
Producer-Consumer problem
Readers-Writers problem
Dining Philosophers problem
Both B & C
Explanation
Readers-Writers and Dining Philosophers (along with Producer-Consumer) are the standard scenarios used to test synchronization primitives.
Q.30 Which of the following represent common security threats to a computer system?
Virus
Anti-virus
Trojan horse
Both A & C
Explanation
Viruses and Trojan horses are types of malware that compromise system security, while anti-virus is a protective tool.
Q.31 Which of the following is an example of a single-user operating system?
DOS
UNIX
Windows
None
Explanation
Disk Operating System (DOS) was designed as a single-user, single-tasking operating system for early personal computers.
Q.32 Which of the following is classified as System Software?
MS-Word
UNIX
Excel
None
Explanation
Operating systems like UNIX are system software because they manage the computer’s hardware and provide a platform for application software.
Q.33 Which of the following are page replacement techniques used by an OS?
Optical replacement
LRU
Both A & B
None
Explanation
LRU (Least Recently Used) is a standard page replacement algorithm. (Note: ‘Optimal’ is a technique, though ‘Optical’ is likely a typo for it).
Q.34 A file virus typically attaches itself to which type of file?
Source file
Object file
Executable file
None
Explanation
File-infector viruses attach themselves to executable files (.exe or .com) to ensure they run when the user opens the program.
Q.35 A program that is currently in the state of execution is known as a?
Job
Process
Instruction
None
Explanation
A process is an active instance of a computer program that is being executed by the CPU.
Q.36 Which of the following is a recognized disk scheduling technique?
Best fit
Long fit
Both
None
Explanation
Disk scheduling techniques include FCFS, SSTF, and SCAN. ‘Best fit’ is a memory allocation strategy, not disk scheduling.
Q.37 Which of the following is NOT an operating system?
DOS
LINUX
UNIX
Compiler
Explanation
A compiler is a language translator that converts source code to machine code; it is not an operating system.
Q.38 Which of the following are examples of Antivirus software?
McAfee
Macafee
Quick Heal
Both B & C
Explanation
McAfee and Quick Heal are well-known security products designed to detect and remove malware.
Q.39 In the 'Waiting' state, what is a process usually busy doing?
CPU burst
Computing
I/O burst
Memory burst
Explanation
Processes in the waiting state are typically performing Input/Output operations or waiting for an I/O event to complete.
Q.40 In operating systems, what does the acronym PCB stand for?
Program Control Block
Process Control Block
Control Block
Memory Burst
Explanation
The Process Control Block (PCB) is a data structure used by the OS to store all the information about a specific process.