Category: Operating System Objective Questions

Operating System Multiple Choice Questions on “Protection concepts”.

1. Which principle states that programs, users and even the systems be given just enough privileges to perform their task?
a) principle of operating system
b) principle of least privilege
c) principle of process scheduling
d) none of the mentioned

Answer: b

2. _______ is an approach to restricting system access to authorized users.
a) Role-based access control
b) Process-based access control
c) Job-based access control
d) None of the mentioned

Answer: a

3. For system protection, a process should access _____________
a) all the resources
b) only those resources for which it has authorization
c) few resources but authorization is not required
d) all of the mentioned

Answer: b

4. The protection domain of a process contains _____________
a) object name
b) rights-set
c) both object name and rights-set
d) none of the mentioned

Answer: c

5. If the set of resources available to the process is fixed throughout the process’s lifetime then its domain is _____________
a) static
b) dynamic
c) neither static nor dynamic
d) none of the mentioned

Answer: a
Clarification: None.

6. Access matrix model for user authentication contains _____________
a) a list of objects
b) a list of domains
c) a function which returns an object’s type
d) all of the mentioned

Answer: d
Clarification: None.

7. Global table implementation of the matrix table contains _____________
a) domain
b) object
c) right-set
d) all of the mentioned

Answer: d
Clarification: None.

8. For a domain _______ is a list of objects together with the operation allowed on these objects.
a) capability list
b) access list
c) both capability and access list
d) none of the mentioned

Answer: a
Clarification: None.

9. Which one of the following is capability based protection system?
a) hydra
b) cambridge CAP system
c) both hydra and cambridge CAP system
d) none of the mentioned

Answer: c
Clarification: None.

10. In UNIX, domain switch is accomplished via _____________
a) file system
b) user
c) superuser
d) none of the mentioned

Answer: a

Operating System Multiple Choice Questions on “CPU Scheduling Algorithms”.

1. Round robin scheduling falls under the category of ____________
a) Non-preemptive scheduling
b) Preemptive scheduling
c) All of the mentioned
d) None of the mentioned

Answer: b
Clarification: None.

2. With round robin scheduling algorithm in a time shared system ____________
a) using very large time slices converts it into First come First served scheduling algorithm
b) using very small time slices converts it into First come First served scheduling algorithm
c) using extremely small time slices increases performance
d) using very small time slices converts it into Shortest Job First algorithm

Answer: a
Clarification: All the processes will be able to get completed.

3. The portion of the process scheduler in an operating system that dispatches processes is concerned with ____________
a) assigning ready processes to CPU
b) assigning ready processes to waiting queue
c) assigning running processes to blocked queue
d) all of the mentioned

Answer: a
Clarification: None.

4. Complex scheduling algorithms ____________
a) are very appropriate for very large computers
b) use minimal resources
c) use many resources
d) all of the mentioned

Answer: a
Clarification: Large computers are overloaded with a greater number of processes.

5. What is FIFO algorithm?
a) first executes the job that came in last in the queue
b) first executes the job that came in first in the queue
c) first executes the job that needs minimal processor
d) first executes the job that has maximum processor needs

Answer: b
Clarification: None.

6. The strategy of making processes that are logically runnable to be temporarily suspended is called ____________
a) Non preemptive scheduling
b) Preemptive scheduling
c) Shortest job first
d) First come First served

Answer: b
Clarification: None.

7. What is Scheduling?
a) allowing a job to use the processor
b) making proper use of processor
c) all of the mentioned
d) none of the mentioned

Answer: a
Clarification: None.

8. There are 10 different processes running on a workstation. Idle processes are waiting for an input event in the input queue. Busy processes are scheduled with the Round-Robin time sharing method. Which out of the following quantum times is the best value for small response times, if the processes have a short runtime, e.g. less than 10ms?
a) tQ = 15ms
b) tQ = 40ms
c) tQ = 45ms
d) tQ = 50ms

Answer: a
Clarification: None.

9. Orders are processed in the sequence they arrive if _______ rule sequences the jobs.
a) earliest due date
b) slack time remaining
c) first come, first served
d) critical ratio

Answer: c
Clarification: None.

10. Which of the following algorithms tends to minimize the process flow time?
a) First come First served
b) Shortest Job First
c) Earliest Deadline First
d) Longest Job First

Answer: b
Clarification: None.

11. Under multiprogramming, turnaround time for short jobs is usually ________ and that for long jobs is slightly ___________
a) Lengthened; Shortened
b) Shortened; Lengthened
c) Shortened; Shortened
d) Shortened; Unchanged

Answer: b
Clarification: None.

12. Which of the following statements are true? (GATE 2010)

I. Shortest remaining time first scheduling may cause starvation
II. Preemptive scheduling may cause starvation
III. Round robin is better than FCFS in terms of response time

a) I only
b) I and III only
c) II and III only
d) I, II and III

Answer: d
Clarification: I) Shortest remaining time first scheduling is a preemptive version of shortest job scheduling. It may cause starvation as shorter processes may keep coming and a long CPU burst process never gets CPU.
II) Preemption may cause starvation. If priority based scheduling with preemption is used, then a low priority process may never get CPU.
III) Round Robin Scheduling improves response time as all processes get CPU after a specified time.

Operating System Multiple Choice Questions on “Memory Management – Memory Allocation”.

1. The main memory accommodates ____________
a) operating system
b) cpu
c) user processes
d) all of the mentioned

Answer: a
Clarification: None.

2. What is the operating system?
a) in the low memory
b) in the high memory
c) either low or high memory (depending on the location of interrupt vector)
d) none of the mentioned

Answer: c
Clarification: None.

3. In contiguous memory allocation ____________
a) each process is contained in a single contiguous section of memory
b) all processes are contained in a single contiguous section of memory
c) the memory space is contiguous
d) none of the mentioned

Answer: a
Clarification: None.

4. The relocation register helps in ____________
a) providing more address space to processes
b) a different address space to processes
c) to protect the address spaces of processes
d) none of the mentioned

Answer: c
Clarification: None.

5. With relocation and limit registers, each logical address must be _______ the limit register.
a) less than
b) equal to
c) greater than
d) none of the mentioned

Answer: a
Clarification: None.

6. The operating system and the other processes are protected from being modified by an already running process because ____________
a) they are in different memory spaces
b) they are in different logical addresses
c) they have a protection algorithm
d) every address generated by the CPU is being checked against the relocation and limit registers

Answer: d
Clarification: None.

7. Transient operating system code is code that ____________
a) is not easily accessible
b) comes and goes as needed
c) stays in the memory always
d) never enters the memory space

Answer: b
Clarification: None.

8. Using transient code, _______ the size of the operating system during program execution.
a) increases
b) decreases
c) changes
d) maintains

Answer: c
Clarification: None.

9. When memory is divided into several fixed sized partitions, each partition may contain ________
a) exactly one process
b) at least one process
c) multiple processes at once
d) none of the mentioned

Answer: a
Clarification: None.

10. In fixed size partition, the degree of multiprogramming is bounded by ___________
a) the number of partitions
b) the CPU utilization
c) the memory size
d) all of the mentioned

Answer: a
Clarification: None

11. The first fit, best fit and worst fit are strategies to select a ______
a) process from a queue to put in memory
b) processor to run the next process
c) free hole from a set of available holes
d) all of the mentioned

Answer: c

Operating System Questions and Answers on “Multimedia System – Compression” and will also be useful for various entrance examinations.

1. What is the full form of MPEG?
a) Motion Pictures Engineering Group
b) Motion Picture Engineers Group
c) Motion Picture Experts Group
d) None of the mentioned

Answer: c
Clarification: None.

2. What is MPEG compression?
a) stores the compression values of each frame
b) stores the differences between successive frames
c) stores multiple frames’ values together
d) none of the mentioned

Answer: b
Clarification: None.

3. What are the levels in QoS?
a) Best effort service
b) Soft QoS
c) Hard QoS
d) All of the mentioned

Answer: d
Clarification: None.

4. The level that treats different types of traffics in different ways, giving certain traffic streams higher priority than other streams and with best efforts, but no guarantees are made ___________
a) Best effort service
b) Soft QoS
c) Worst effort service
d) Hard QoS

Answer: b
Clarification: None.

5. The quality of service requirements are guaranteed in ___________
a) Best effort service
b) Soft QoS
c) Worst effort service
d) Hard QoS

Answer: d
Clarification: None.

6. What are the factors that define QoS?
a) Throughput
b) Jitter
c) Delay
d) All of the mentioned

Answer: d
Clarification: None.

7. Delay and Jitter ___________
a) mean the same thing
b) are two completely different things
c) all of the mentioned
d) none of the mentioned

Answer: b
Clarification: None.

8. What is the Delay?
a) the time from when a request is first submitted to when the desired result is produced
b) the delay that occurs during playback of the stream
c) how the errors are handled during the transmission and processing of continuous media
d) none of the mentioned

Answer: a
Clarification: None.

9. What is Admission control?
a) the delay that occurs during playback of the stream
b) the practice of admitting a request for service only if the server has sufficient resources to satisfy the request
c) how the errors are handled during the transmission and processing of continuous media
d) none of the mentioned

Answer: b
Clarification: None.

10. An admission control scheme assigns a __________ to each type of resource.
a) processor
b) memory location
c) resource manager
d) all of the mentioned

Answer: c

Operating System Multiple Choice Questions on “Thread Pools”.

1. Thread pools are useful when ____________
a) when we need to limit the number of threads running in the application at the same time
b) when we need to limit the number of threads running in the application as a whole
c) when we need to arrange the ordering of threads
d) none of the mentioned

Answer: a

2. Instead of starting a new thread for every task to execute concurrently, the task can be passed to a ___________
a) process
b) thread pool
c) thread queue
d) none of the mentioned

Answer: b

3. Each connection arriving at multi threaded servers via network is generally ____________
a) is directly put into the blocking queue
b) is wrapped as a task and passed on to a thread pool
c) is kept in a normal queue and then sent to the blocking queue from where it is dequeued
d) none of the mentioned

Answer: b

4. What is the idea behind thread pools?
a) a number of threads are created at process startup and placed in a pool where they sit and wait for work
b) when a process begins, a pool of threads is chosen from the many existing and each thread is allotted equal amount of work
c) all threads in a pool distribute the task equally among themselves
d) none of the mentioned

Answer: a
Clarification: None.

5. If the thread pool contains no available thread ____________
a) the server runs a new process
b) the server goes to another thread pool
c) the server demands for a new pool creation
d) the server waits until one becomes free

Answer: d
Clarification: None.

6. Thread pools help in ____________
a) servicing multiple requests using one thread
b) servicing a single request using multiple threads from the pool
c) faster servicing of requests with an existing thread rather than waiting to create a new thread
d) none of the mentioned

Answer: c
Clarification: None.

7. Thread pools limit the number of threads that exist at any one point, hence ____________
a) not letting the system resources like CPU time and memory exhaust
b) helping a limited number of processes at a time
c) not serving all requests and ignoring many
d) none of the mentioned

Answer: a
Clarification: None.

8. The number of the threads in the pool can be decided on factors such as ____________
a) number of CPUs in the system
b) amount of physical memory
c) expected number of concurrent client requests
d) all of the mentioned

Answer: d

Basic Operating System Questions and Answers on “File System Implementation – Allocation Methods”.

1. A device driver can be thought of like a translator. Its input consists of _____ commands and output consists of _______ instructions.
a) high level, low level
b) low level, high level
c) complex, simple
d) low level, complex

Answer: a
Clarification: None.

2. The file organization module knows about _____________
a) files
b) logical blocks of files
c) physical blocks of files
d) all of the mentioned

Answer: d
Clarification: None.

3. Metadata includes _____________
a) all of the file system structure
b) contents of files
c) both file system structure and contents of files
d) none of the mentioned

Answer: c
Clarification: None.

4. For each file there exists a ___________ that contains information about the file, including ownership, permissions and location of the file contents.
a) metadata
b) file control block
c) process control block
d) all of the mentioned

Answer: b
Clarification: None.

5. For processes to request access to file contents, they need _____________
a) to run a seperate program
b) special interrupts
c) to implement the open and close system calls
d) none of the mentioned

Answer: c
Clarification: None.

6. During compaction time, other normal system operations _______ be permitted.
a) can
b) cannot
c) is
d) none of the mentioned

Answer: b
Clarification: None.

7. When in contiguous allocation the space cannot be extended easily?
a) the contents of the file have to be copied to a new space, a larger hole
b) the file gets destroyed
c) the file will get formatted and lost all its data
d) none of the mentioned

Answer: a
Clarification: None.

8. In the linked allocation, the directory contains a pointer to which block?
I. first block
II. last block
a) I only
b) II only
c) Both I and II
d) Neither I nor II

Answer: c
Clarification: None.

9. There is no __________ with linked allocation.
a) internal fragmentation
b) external fragmentation
c) starvation
d) all of the mentioned

Answer: b
Clarification: None.

10. What is the major disadvantage with a linked allocation?
a) internal fragmentation
b) external fragmentation
c) there is no sequential access
d) there is only sequential access

Answer: d
Clarification: None.

11. What if a pointer is lost or damaged in a linked allocation?
a) the entire file could get damaged
b) only a part of the file would be affected
c) there would not be any problems
d) none of the mentioned

Answer: a
Clarification: None.

12. FAT stands for _____________
a) File Attribute Transport
b) File Allocation Table
c) Fork At Time
d) None of the mentioned

Answer: b
Clarification: None.

13. By using FAT, random access time is __________
a) the same
b) increased
c) decreased
d) not affected

Answer: c