set-8

351. Which of the following capabilities is required for a system program to execute more than one program at a time?

1. Word processing

2. Virtual memory

3. Compiling

4. Multitasking

Show me the answer

Answer: 4. Multitasking

Explanation:

• Multitasking: Multitasking is the capability of an operating system to execute multiple programs simultaneously by switching between them. This allows efficient utilization of CPU and other resources.

• Conclusion: Multitasking is essential for executing multiple programs at the same time.

352. A critical region is:

1. A program segment that has not been proved bug-free

2. A program segment that often causes unexpected system crashes

3. A program segment where shared resources are accessed

4. One which is enclosed by a pair of P and V operations on semaphores

Show me the answer

Answer: 3. A program segment where shared resources are accessed

Explanation:

• Critical Region: A critical region is a segment of code where shared resources are accessed. To prevent race conditions, only one process can execute its critical region at a time.

• Conclusion: The critical region is where shared resources are accessed.

353. Which of the following addressing modes facilitates access to an operand whose location is defined relative to the beginning of the data structure in which it appears?

1. Ascending

2. Index

3. Sorting

4. Indirect

Show me the answer

Answer: 2. Index

Explanation:

• Index Addressing Mode: In index addressing mode, the effective address of the operand is calculated by adding a constant value to the contents of a register (index register). This is useful for accessing elements in arrays or data structures.

• Conclusion: Index addressing mode facilitates access to operands relative to the beginning of a data structure.

354. The register or main memory location which contains the effective address of the operand is known as:

1. Pointer

2. Special location

3. Indexed register

4. Scratch pad

Show me the answer

Answer: 1. Pointer

Explanation:

• Pointer: A pointer is a register or memory location that holds the effective address of an operand. It is used to indirectly access data.

• Conclusion: The register or memory location containing the effective address is called a pointer.

355. System programs such as compilers are designed so that they are:

1. Re-entrant

2. Serially usable

3. Non-reusable

4. Recursive

Show me the answer

Answer: 1. Re-entrant

Explanation:

• Re-entrant Programs: Re-entrant programs can be interrupted in the middle of execution and called again before the previous execution completes. This is essential for system programs like compilers to handle multiple users or tasks.

• Conclusion: System programs like compilers are designed to be re-entrant.

356. Special software to create a job queue is called a:

1. Drive

2. Interpreter

3. Spooler

4. Linkage editor

Show me the answer

Answer: 3. Spooler

Explanation:

• Spooler: A spooler is a software component that manages job queues, particularly for printing or other I/O operations. It allows multiple jobs to be queued and processed sequentially.

• Conclusion: A spooler creates and manages job queues.

357. The most common security failure is:

1. Carelessness by users

2. Depending on passwords

3. Too much emphasis on preventing physical access

4. Insufficient technology used to prevent breaches

Show me the answer

Answer: 1. Carelessness by users

Explanation:

• Security Failures: The most common security failures are caused by human errors, such as weak passwords, sharing credentials, or falling for phishing attacks.

• Conclusion: User carelessness is the primary cause of security failures.

358. A public key encryption system:

1. Allows anyone to decode the transmission

2. Allows only the correct sender to decode the data

3. Allows only the correct receiver to decode the data

4. Does not encode the data before transmitting it

Show me the answer

Answer: 3. Allows only the correct receiver to decode the data

Explanation:

• Public Key Encryption: In public key encryption, the sender uses the receiver's public key to encrypt the data, and only the receiver's private key can decrypt it. This ensures that only the intended receiver can decode the data.

• Conclusion: Public key encryption ensures secure communication by allowing only the correct receiver to decode the data.

359. Supervisor state is:

1. Never used

2. Entered by programs when they enter the processor

3. Required to perform any I/O

4. Only allowed to the operating system

Show me the answer

Answer: 4. Only allowed to the operating system

Explanation:

• Supervisor State: The supervisor state (or kernel mode) is a privileged mode of operation where the operating system can execute instructions that are not available to user programs. It is used for critical tasks like memory management and I/O operations.

• Conclusion: The supervisor state is restricted to the operating system.

360. A high paging rate:

1. May cause a high I/O rate

2. Keeps the system running well

3. Is a symptom of too much processor activity

4. Always creates a slow system

Show me the answer

Answer: 1. May cause a high I/O rate

Explanation:

• High Paging Rate: A high paging rate indicates frequent page faults, which require data to be read from or written to secondary storage. This increases the I/O rate and can degrade system performance.

• Conclusion: A high paging rate may lead to increased I/O activity.

361. Round robin scheduling is essentially the preemptive version of:

1. FIFO

2. FILO

3. FCFS

4. Longest time first

Show me the answer

Answer: 1. FIFO

Explanation:

• Round Robin Scheduling: Round robin scheduling is a preemptive version of FIFO (First-In-First-Out) scheduling. Each process is given a fixed time slice (quantum) to execute, and the CPU switches between processes after each quantum.

• Conclusion: Round robin is the preemptive version of FIFO.

362. If the number of bits in the virtual address of a program is 12 and the page size is 0.5 KB, the number of pages in the virtual address space is:

1. 16

2. 32

3. 64

4. 128

Show me the answer

Answer: 4. 128

Explanation:

• Virtual Address Space: The virtual address space is determined by the number of bits in the virtual address. For 12 bits, the total addressable space is:

  $$2^{12} = 4096 \text{ bytes}$$
• Page Size: The page size is 0.5 KB (512 bytes). The number of pages is:

  $$\frac{4096}{512} = 8$$
• Conclusion: The number of pages is 8 (assuming a typo in the question).

363. In which of the storage placement strategies is a program placed in the largest available hole in the main memory?

1. Best fit

2. Worst fit

3. First fit

4. Buddy

Show me the answer

Answer: 2. Worst fit

Explanation:

• Worst Fit: The worst fit strategy allocates the largest available hole in memory to a process. This can lead to inefficient memory utilization but may reduce fragmentation in some cases.

• Conclusion: Worst fit places a program in the largest available hole.

364. For how many processes which are sharing common data does Dekker’s algorithm implement mutual exclusion?

1. 1

2. 2

3. 3

4. 4

Show me the answer

Answer: 2. 2

Explanation:

• Dekker’s Algorithm: Dekker’s algorithm is a mutual exclusion algorithm designed for two processes. It ensures that only one process can enter the critical section at a time.

• Conclusion: Dekker’s algorithm works for two processes.

365. A disk scheduling algorithm in an operating system causes the disk arm to move back and forth across the disk surface in order to service all requests in its path. This is a:

1. First come first served

2. Scan

3. Shortest Seek Time First (SSTF)

4. FIFO

Show me the answer

Answer: 2. Scan

Explanation:

• SCAN Algorithm: The SCAN algorithm moves the disk arm in one direction, servicing all requests in its path, and then reverses direction. This reduces seek time and improves efficiency.

• Conclusion: The SCAN algorithm causes the disk arm to move back and forth.

366. Round-robin scheduling:

1. Allows interactive tasks quicker access to the processor

2. Is quite complex to implement

3. Gives each task the same chance at the processor

4. Allows processor-bound tasks more time in the processor

Show me the answer

Answer: 3. Gives each task the same chance at the processor

Explanation:

• Round Robin Scheduling: Round robin scheduling provides fair CPU allocation by giving each task an equal time slice (quantum). This ensures that all tasks get an equal chance to execute.

• Conclusion: Round robin gives each task the same chance at the processor.

367. Inter-process communication:

1. Is required for all processes

2. Is usually done via disk drives

3. Is never necessary

4. Allows processes to synchronize activity

Show me the answer

Answer: 4. Allows processes to synchronize activity

Explanation:

• Inter-Process Communication (IPC): IPC allows processes to communicate and synchronize their activities. Common IPC mechanisms include shared memory, message passing, and pipes.

• Conclusion: IPC enables process synchronization.

368. Fork is:

1. The dispatching of a task

2. The creation of a new job

3. The creation of a new process

4. Increasing the priority of a task

Show me the answer

Answer: 3. The creation of a new process

Explanation:

• Fork: The fork system call creates a new process by duplicating the existing process. The new process is called the child process, and the original process is called the parent process.

• Conclusion: Fork is used to create a new process.

369. A process is another name for:

1. A job

2. Paging

3. A task

4. The operating system dispatcher

Show me the answer

Answer: 3. A task

Explanation:

• Process: A process is an instance of a program in execution. It is also referred to as a task in some contexts.

• Conclusion: A process is another name for a task.

370. Relocation bits used by relocating loader are specified (generated by):

1. Relocating loader itself

2. Assembler or translator

3. Linker

4. Macro processor

Show me the answer

Answer: 2. Assembler or translator

Explanation:

• Relocation Bits: Relocation bits are generated by the assembler or translator to indicate which parts of the program need to be adjusted during loading.

• Conclusion: The assembler or translator generates relocation bits.

371. Device independence:

1. Allows the computer to run without I/O devices

2. Makes all devices look the same to the operating system

3. Allows programs to be written more easily

4. Allows tape drives to be substituted for disk drives

Show me the answer

Answer: 3. Allows programs to be written more easily

Explanation:

• Device Independence: Device independence allows programs to interact with devices without needing to know the specific details of the hardware. This simplifies programming and improves portability.

• Conclusion: Device independence makes programming easier.

372. User-Friendly Systems are:

1. Required for object-oriented programming

2. Easy to develop

3. Common among traditional mainframe operating systems

4. Becoming more common

Show me the answer

Answer: 4. Becoming more common

Explanation:

• User-Friendly Systems: Modern operating systems and applications are designed to be user-friendly, with intuitive interfaces and features that make them accessible to a wide range of users.

• Conclusion: User-friendly systems are increasingly common.

373. Disk scheduling includes deciding:

1. Which disk should be accessed next

2. The order in which disk access requests must be serviced

3. The physical location of the file

4. The logical location of the file

Show me the answer

Answer: 2. The order in which disk access requests must be serviced

Explanation:

• Disk Scheduling: Disk scheduling determines the order in which disk access requests are serviced to minimize seek time and improve performance.

• Conclusion: Disk scheduling focuses on the order of disk access requests.

374. Which of the following translator programs convert assembly language program to object program?

1. Assembler

2. Macro processor

3. Compiler

4. Linker

Show me the answer

Answer: 1. Assembler

Explanation:

• Assembler: An assembler converts assembly language programs into machine code (object programs).

• Conclusion: The assembler translates assembly language to object code.

375. Data encryption:

1. Is mostly used by public networks

2. Is mostly used by financial networks

3. Cannot be used by private installations

4. Is not necessary, since data cannot be intercepted

Show me the answer

Answer: 2. Is mostly used by financial networks

Explanation:

• Data Encryption: Data encryption is widely used in financial networks to protect sensitive information during transmission.

• Conclusion: Financial networks heavily rely on data encryption.

376. Seeks analysis:

1. Is used for analyzing paging problems

2. Is used for analyzing device busy problems

3. Is used for analyzing control-unit busy problems

4. Is only shown on real-time displays

Show me the answer

Answer: 2. Is used for analyzing device busy problems

Explanation:

• Seeks Analysis: Seeks analysis is used to study and optimize disk access patterns, particularly to address device busy problems.

• Conclusion: Seeks analysis helps analyze device busy problems.

377. Swapping:

1. Works best with many small partitions

2. Allows many programs to use memory simultaneously

3. Allows each program in turn to use the memory

4. Does not work with overlaying

Show me the answer

Answer: 3. Allows each program in turn to use the memory

Explanation:

• Swapping: Swapping allows multiple programs to share memory by moving them between main memory and secondary storage. Each program gets a turn to use the memory.

• Conclusion: Swapping enables programs to take turns using memory.

378. Feedback queue:

1. Are very easy to implement

2. Dispatch tasks according to execution characteristics

3. Are used to favor real-time tasks

4. Require manual intervention to implement properly

Show me the answer

Answer: 2. Dispatch tasks according to execution characteristics

Explanation:

• Feedback Queue: A feedback queue is a scheduling mechanism that adjusts the priority of tasks based on their execution history. Tasks that use too much CPU time are moved to lower-priority queues.

• Conclusion: Feedback queues dispatch tasks based on execution characteristics.

379. A file organization component of a VSAM file is:

1. Relative record data set

2. Entry sequential data set

3. Keyed sequential data set

4. All of the above

Show me the answer

Answer: 4. All of the above

Explanation:

• VSAM File Organization: VSAM (Virtual Storage Access Method) supports multiple file organizations, including relative record, entry sequential, and keyed sequential data sets.

• Conclusion: All the given options are components of VSAM file organization.

380. The file structure that redefines its first record at a basic of zero uses the term:

1. Relative organization

2. Dynamic reallocation

3. Key fielding

4. Hashing

Show me the answer

Answer: 1. Relative organization

Explanation:

• Relative Organization: In relative file organization, records are accessed using relative record numbers, starting from zero.

• Conclusion: Relative organization redefines the first record at a base of zero.

381. File record length:

1. Should always be fixed

2. Should always be variable

3. Depends upon the size of the file

4. Should be chosen to match the data characteristics

Show me the answer

Answer: 4. Should be chosen to match the data characteristics

Explanation:

• File Record Length: The record length should be chosen based on the characteristics of the data being stored. Fixed or variable record lengths can be used depending on the application.

• Conclusion: Record length should match data characteristics.

382. An incremental backup:

1. Should be done each month

2. Uses more tapes

3. Saves all files

4. Saves only files that have recently changed

Show me the answer

Answer: 4. Saves only files that have recently changed

Explanation:

• Incremental Backup: An incremental backup saves only the files that have changed since the last backup. This reduces the amount of data to be backed up and speeds up the process.

• Conclusion: Incremental backups save only recently changed files.

383. A partitioned data set is most used for:

1. Program or source library

2. Storing backup information

3. Storing program data

4. Storing ISAM file

Show me the answer

Answer: 1. Program or source library

Explanation:

• Partitioned Data Set (PDS): A PDS is commonly used to store program source code or libraries. It allows multiple members (files) to be stored within a single dataset.

• Conclusion: PDS is primarily used for program or source libraries.

384. System generation:

1. Is always quite simple

2. Is always very difficult

3. Varies in difficulty between systems

4. Requires extensive tools to be understandable

Show me the answer

Answer: 3. Varies in difficulty between systems

Explanation:

• System Generation: System generation (sysgen) is the process of configuring and installing an operating system. The difficulty of sysgen varies depending on the complexity of the system and the hardware.

• Conclusion: System generation difficulty varies between systems.

385. Object code:

1. Is ready to execute

2. Is the output of compilers, but not assemblers

3. Must be “loaded” before execution

4. Must be rewritten before execution

Show me the answer

Answer: 3. Must be “loaded” before execution

Explanation:

• Object Code: Object code is the output of a compiler or assembler. It is not directly executable and must be linked and loaded into memory before execution.

• Conclusion: Object code requires loading before execution.

386. Virtual memory is:

1. Simple to implement

2. Used in all major commercial operating systems

3. Less efficient in utilization of memory

4. Useful when fast I/O devices are not available

Show me the answer

Answer: 2. Used in all major commercial operating systems

Explanation:

• Virtual Memory: Virtual memory is a widely used technique in modern operating systems to manage memory efficiently. It allows processes to use more memory than physically available by swapping data between RAM and secondary storage.

• Conclusion: Virtual memory is used in all major commercial operating systems.

387. System maintenance:

1. Is usually not necessary

2. Is necessary on all systems, regardless of how good

3. Is not required if the system is well written

4. Always requires several programs

Show me the answer

Answer: 2. Is necessary on all systems, regardless of how good

Explanation:

• System Maintenance: System maintenance is essential to ensure the continued performance, security, and reliability of a system. It is necessary for all systems, regardless of their initial quality.

• Conclusion: System maintenance is necessary for all systems.

388. Which of the following statements is not true?

1. Time sharing is an example of multiprogramming

2. JCL is used only to communicate between systems programmers

3. A batch file contains a series of operating system commands

4. The primary function of operating systems is to make the computer hardware easily usable

Show me the answer

Answer: 2. JCL is used only to communicate between systems programmers

Explanation:

• JCL (Job Control Language): JCL is used to define and control batch jobs in mainframe systems. It is not limited to communication between systems programmers.

• Conclusion: The statement about JCL is not true.

389. What scheduling algorithm allows processes that are logically runnable to be temporarily suspended?

1. Preemptive scheduling

2. FIFO

3. Non-preemptive scheduling

4. FCFS

Show me the answer

Answer: 1. Preemptive scheduling

Explanation:

• Preemptive Scheduling: Preemptive scheduling allows the operating system to temporarily suspend a running process and allocate the CPU to another process. This ensures fair CPU allocation and responsiveness.

• Conclusion: Preemptive scheduling allows processes to be temporarily suspended.

390. The term ‘polling’ in a computer means a process by which a computer system:

1. Detects/corrects errors

2. Multiplexes the inputs and updates the memory accordingly

3. Decides the correct alternative by analyzing several ones

4. Inquiries to see if a terminal has any transaction to send

Show me the answer

Answer: 4. Inquiries to see if a terminal has any transaction to send

Explanation:

• Polling: Polling is a process where the CPU repeatedly checks the status of devices (e.g., terminals) to see if they have data to send or receive.

• Conclusion: Polling involves inquiring about device status.

391. In a magnetic disk, data is recorded in a set of concentric tracks which are subdivided into:

1. Periods

2. Zones

3. Sectors

4. Groups

Show me the answer

Answer: 3. Sectors

Explanation:

• Sectors: A magnetic disk is divided into concentric tracks, which are further subdivided into sectors. Each sector stores a fixed amount of data.

• Conclusion: Tracks are subdivided into sectors.

392. Which of the following is true for machine language?

1. Repeated execution of program segments

2. Depicting flow of data in a system

3. A sequence of instructions which, when followed properly, solves a problem

4. The language which communicates with the computer using only the binary digits 1 and 0

Show me the answer

Answer: 4. The language which communicates with the computer using only the binary digits 1 and 0

Explanation:

• Machine Language: Machine language consists of binary instructions that the computer's processor can execute directly. It uses only 1s and 0s to represent instructions and data.

• Conclusion: Machine language communicates with the computer using binary digits.

393. The LRU algorithm:

1. Pages out pages that have been used recently

2. Pages out pages that have not been used recently

3. Pages out pages that have been least used recently

4. Pages out the first page in a given area

Show me the answer

Answer: 3. Pages out pages that have been least used recently

Explanation:

• LRU Algorithm: The Least Recently Used (LRU) page replacement algorithm replaces the page that has not been used for the longest time.

• Conclusion: LRU pages out the least recently used pages.

394. A linker:

1. Creates a load module

2. Is not necessary with variable partitions

3. Must be run after the loader

4. Is not needed with a good compiler

Show me the answer

Answer: 1. Creates a load module

Explanation:

• Linker: A linker combines object modules into a single load module, resolving external references and preparing the program for execution.

• Conclusion: The linker creates a load module.

395. Global locks:

1. Synchronize access to local resources

2. Synchronize access to global resources

3. Are used to avoid local locks

4. Prevent access to global resources

Show me the answer

Answer: 2. Synchronize access to global resources

Explanation:

• Global Locks: Global locks are used to synchronize access to shared resources that are accessed by multiple processes or threads.

• Conclusion: Global locks synchronize access to global resources.

396. The dynamic allocation of storage areas with VSAM files is accomplished by:

1. Hashing

2. Overflow areas

3. Control splits

4. Relative recording

Show me the answer

Answer: 3. Control splits

Explanation:

• VSAM Dynamic Allocation: VSAM uses control splits to dynamically allocate storage areas when the dataset grows.

• Conclusion: Control splits enable dynamic allocation in VSAM files.

397. Which of the following refers to associative memory?

1. The address of the data is generated by the CPU

2. The address of the data is supplied by the user

3. There is no need for an address, i.e., the data is used as an address

4. The data are accessed sequentially

Show me the answer

Answer: 3. There is no need for an address, i.e., the data is used as an address

Explanation:

• Associative Memory: Associative memory (or content-addressable memory) allows data to be accessed based on its content rather than a specific address.

• Conclusion: Associative memory uses data as an address.

398. Link encryption:

1. Is more secure than end-to-end encryption

2. Is less secure than end-to-end encryption

3. Cannot be used in a public network

4. Is used only to debug

Show me the answer

Answer: 2. Is less secure than end-to-end encryption

Explanation:

• Link Encryption: Link encryption encrypts data only over a specific link (e.g., between two nodes). It is less secure than end-to-end encryption, which encrypts data from the source to the destination.

• Conclusion: Link encryption is less secure than end-to-end encryption.

399. Which of the following is a characteristic of an operating system?

1. Resource management

2. Memory management

3. Error recovery

4. All of the above

Show me the answer

Answer: 4. All of the above

Explanation:

• Operating System Characteristics: An operating system manages resources, memory, and error recovery, among other tasks.

• Conclusion: All the given options are characteristics of an operating system.

400. Files can have:

1. Read access

2. Write access

3. Copy access

4. All of the above

Show me the answer

Answer: 4. All of the above

Explanation:

• File Access: Files can have various access permissions, including read, write, and copy access.

• Conclusion: Files can have all the given access types.