This section contains carefully selected MCQs and Previous Year Questions with explanations to help students understand concepts and prepare effectively for examinations, interviews, and competitive tests.
Q: 1The first instruction of bootstrap loader program of an operating system is stored in
Option B
When a computer is powered on, the bootstrap loader is responsible for starting the operating system. The first instruction of the bootstrap loader must be available immediately after power-on, even before RAM or the hard disk is accessed.
For this reason, it is stored in BIOS (Basic Input-Output System), which resides in ROM.
Q: 2
Match the virtual memory terminologies in Column I to their descriptions in Column II:
| Column I | Column II |
|---|---|
| a. Virtual address | i. The virtual storage assigned to a process. |
| b. Virtual address space | ii. The range of memory addresses available to a process. |
| c. Address space | iii. The address of a storage location in main memory. |
| d. Real address | iv. The address assigned to a location in virtual memory to allow that location to be accessed as though it were part of main memory. |
Choose the correct option:
Option B
Virtual Memory is a memory management technique that gives an application the illusion of having a large, continuous block of memory, even though it may be physically fragmented or partially stored on disk.
| TERM | DESCRIPTION |
|---|---|
| Virtual Address | A virtual address is the address assigned to a location in virtual memory. It allows the CPU to access data as if it were in the main memory. |
| Virtual Address Space | This refers to the total virtual storage assigned to a process. It represents the range of virtual addresses a process can use. |
| Address Space | The address space defines the range of memory addresses available to a process (virtual or physical). |
| Real Address | The real address (also called physical address) refers to the actual location in the main memory (RAM). |
Q: 3Execution of an operating system is initiated by a program called the ________.
Option C
When a computer system is powered on, a small program called the bootstrap program starts executing first. This program is responsible for loading the operating system into main memory and transferring control to it so that the OS can begin execution.
Q: 4Which of the following is a function of an operating system?
I. Memory Allocation
II. Resource Utilization
Option C
An Operating System (OS) acts as an interface between the user and computer hardware. It manages different system resources such as memory, CPU, files, and input/output devices to ensure efficient operation of the computer system.
One important function of the operating system is Memory Allocation, where it allocates memory space to different programs and processes as needed.
Another function is Resource Utilization, where the operating system manages CPU time, memory, and devices efficiently so that system resources are properly utilized.
| Operating System Function | Description |
|---|---|
| Process Management | Manages creation, execution, and termination of processes. |
| Memory Management | Allocates and deallocates memory to programs and processes. |
| File Management | Organizes, stores, and controls access to files and folders. |
| Device Management | Controls input and output devices such as printer, keyboard, and disk. |
| Resource Allocation | Distributes CPU time, memory, and devices among users and programs. |
| Security and Protection | Protects data and programs from unauthorized access. |
| User Interface | Provides communication between user and computer through CLI or GUI. |
| Error Detection | Detects and handles hardware and software errors. |
| Scheduling | Decides which process will use CPU and for how much time. |
| Accounting | Keeps track of system usage and resource consumption. |
| Networking | Manages communication and data sharing between connected computers. |
| Program Execution | Loads and executes application programs in memory. |
Q: 5Which of the following statement is INCORRECT?
Option C
In an operating system, there are two execution modes, User Mode and Kernel Mode.
Kernel Mode is the most privileged mode, where the system has complete access to hardware and memory, while User Mode has restricted access.
When a program needs to perform system-level operations, it makes a system call, which switches execution from user mode to kernel mode.
If a program crashes while running in kernel mode, it can affect the entire system because kernel mode controls all critical resources.
Therefore, the whole system may crash or become unstable, not just that single program.
Q: 6Which of the following statements is FALSE?
Option A
An Operating System (OS) acts as an interface between the user and the computer hardware. It manages processes, memory, files, and I/O devices.
To perform these tasks efficiently, the operating system relies on concepts such as interrupts, traps, bootstrap programs, and the kernel.
Option (A) : False
The statement, a trap is a hardware-generated interrupt caused either by an error or a user request is false because a trap is a software-generated interrupt. A trap occurs when:
Option (B) : True
Modern operating systems are interrupt-driven. Interrupts inform the OS that some event requires attention. The CPU executes processes and responds to interrupts generated by hardware devices.
Option (C) : True
When a computer is powered on or restarted, a small program called the bootstrap program (bootloader) is executed. Its job is to:
Option (D) : True
The kernel is the core part of the operating system. It is the program that runs continuously while the computer is operating. It remains in memory throughout the system's operation and is responsible for:
Q: 7If a branch instruction causes a change in control flow during pipelining,
Option B
Pipelining is a technique in CPUs where multiple instructions are overlapped in execution to improve performance. A branch instruction changes the normal sequential flow of execution by jumping to a different memory address. This can cause a control hazard, because the CPU may have already fetched instructions following the branch, which may no longer be correct.
Q: 8Which of the following is a Linux System Call for Interprocess Communication (IPC)?
Option A
In Linux, processes often need to communicate and share data with each other, this is called Interprocess Communication (IPC). Linux provides several IPC mechanisms like pipes, message queues, shared memory, and semaphores.
The semctl system call is used to control and manage semaphores, which are synchronization tools that help processes coordinate access to shared resources.
| IPC MECHANISM | SYSTEM CALL | PURPOSE |
|---|---|---|
| Pipes | pipe() | Communicate between parent and child processes. |
| Message Queues | msgsnd(), msgrcv() | Send and receive messages between processes. |
| Shared Memory | shmget(), shmat() | Allow processes to access common memory space. |
| Semaphores | semctl(), semget() | Synchronize process execution and resource access. |
Q: 9
Match the following:
| List—1 | List—2 |
|---|---|
| i. Batch Processing System | A. Meeting Time Constraint |
| ii. Multi Programming | B. Good Response Time |
| iii. Time Sharing | C. Resource Utilization |
| iv. Real Time | D. CPU Idle Time |
Option A
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