Category: Operating System Objective Questions

Operating System Multiple Choice Questions on “Distributed Operating System – Types & Resource Sharing”.

1. What is not true about a distributed system?
a) It is a collection of processor
b) All processors are synchronized
c) They do not share memory
d) None of the mentioned

Answer: b

2. What are the characteristics of processor in distributed system?
a) They vary in size and function
b) They are same in size and function
c) They are manufactured with single purpose
d) They are real-time devices

Answer: a

3. What are the characteristics of a distributed file system?
a) Its users, servers and storage devices are dispersed
b) Service activity is not carried out across the network
c) They have single centralized data repository
d) There are multiple dependent storage devices

Answer: a

4. What is not a major reason for building distributed systems?
a) Resource sharing
b) Computation speedup
c) Reliability
d) Simplicity

Answer: d

5. What are the types of distributed operating system?
a) Network Operating system
b) Zone based Operating system
c) Level based Operating system
d) All of the mentioned

Answer: a
Clarification: None.

6. What are characteristic of Network Operating Systems?
a) Users are aware of multiplicity of machines
b) They are transparent
c) They are simple to use
d) All of the mentioned

Answer: a

7. How is access to resources of various machines is done?
a) Remote logging using ssh or telnet
b) Zone are configured for automatic access
c) FTP is not used
d) All of the mentioned

Answer: a
Clarification: None.

8. What are the characteristics of Distributed Operating system?
a) Users are aware of multiplicity of machines
b) Access is done like local resources
c) Users are aware of multiplicity of machines
d) They have multiple zones to access files

Answer: b
Clarification: None.

9. What are the characteristics of data migration?
a) transfer data by entire file or immediate portion required
b) transfer the computation rather than the data
c) execute an entire process or parts of it at different sites
d) none of the mentioned

Answer: a
Clarification: None.

10. What are the characteristics of computation migration?
a) transfer data by entire file or immediate portion required
b) transfer the computation rather than the data
c) execute an entire process or parts of it at different sites
d) none of the mentioned

Answer: b
Clarification: None.

11. What are the characteristics of process migration?
a) transfer data by entire file or immediate portion required
b) transfer the computation rather than the data
c) execute an entire process or parts of it at different sites
d) none of the mentioned

Answer: c
Clarification: None.

Operating System Multiple Choice Questions on “Basics”.

1. What is an operating system?
a) collection of programs that manages hardware resources
b) system service provider to the application programs
c) interface between the hardware and application programs
d) all of the mentioned

Answer: d
Clarification: An Operating System acts as an intermediary between user/user applications/application programs and hardware. It is a program that manages hardware resources. It provides services to application programs.

2. To access the services of operating system, the interface is provided by the ___________
a) System calls
b) API
c) Library
d) Assembly instructions

Answer: a
Clarification: To access services of the Operating System an interface is provided by the System Calls. Generally, these are functions written in C and C++. Open, Close, Read, Write are some of most prominently used system calls.

3. Which one of the following is not true?
a) kernel is the program that constitutes the central core of the operating system
b) kernel is the first part of operating system to load into memory during booting
c) kernel is made of various modules which can not be loaded in running operating system
d) kernel remains in the memory during the entire computer session

Answer: c
Clarification: Kernel is the first program which is loaded in memory when OS is loading as well as it remains in memory till OS is running. Kernel is the core part of the OS which is responsible for managing resources, allowing multiple processes to use the resources and provide services to various processes. Kernel modules can be loaded and unloaded in run-time i.e. in running OS.

4. Which one of the following error will be handle by the operating system?
a) power failure
b) lack of paper in printer
c) connection failure in the network
d) all of the mentioned

Answer: d
Clarification: All the mentioned errors are handled by OS. The OS is continuously monitoring all of its resources. Also, the OS is constantly detecting and correcting errors.

5. What is the main function of the command interpreter?
a) to get and execute the next user-specified command
b) to provide the interface between the API and application program
c) to handle the files in operating system
d) none of the mentioned

Answer: a
Clarification: The main function of command interpreter is to get and execute the next user-specified command. Command Interpreter checks for valid command and then runs that command else it will throw an error.

6. In Operating Systems, which of the following is/are CPU scheduling algorithms?
a) Round Robin
b) Shortest Job First
c) Priority
d) All of the mentioned

Answer: d
Clarification: In Operating Systems, CPU scheduling algorithms are:
i) First Come First Served scheduling
ii) Shortest Job First scheduling
iii) Priority scheduling
iv) Round Robin scheduling
v) Multilevel Queue scheduling
vi) Multilevel Feedback Queue scheduling
All of these scheduling algorithms have their own advantages and disadvantages.

7. If a process fails, most operating system write the error information to a ______
a) log file
b) another running process
c) new file
d) none of the mentioned

Answer: a
Clarification: If a process fails, most operating systems write the error information to a log file. Log file is examined by the debugger, to find out what is the actual cause of that particular problem. Log file is useful for system programmers for correcting errors.

8. Which facility dynamically adds probes to a running system, both in user processes and in the kernel?
a) DTrace
b) DLocate
c) DMap
d) DAdd

Answer: a
Clarification: A facility that dynamically adds probes to a running system, both in user process and in the kernel is called DTrace. This is very much useful in troubleshooting kernels in real-time.

9. Which one of the following is not a real time operating system?
a) VxWorks
b) QNX
c) RTLinux
d) Palm OS

Answer: d
Clarification: VxWorks, QNX & RTLinux are real-time operating systems. Palm OS is a mobile operating system. Palm OS is developed for Personal Digital Assistants (PDAs).

10. The OS X has ____________
a) monolithic kernel
b) hybrid kernel
c) microkernel
d) monolithic kernel with modules

Answer: b
Clarification: OS X has a hybrid kernel. Hybrid kernel is a combination of two different kernels. OS X is developed by Apple and originally it is known as Mac OS X.

Operating System MCQs on “The Classic Synchronization Problems”

1. The bounded buffer problem is also known as ____________
a) Readers – Writers problem
b) Dining – Philosophers problem
c) Producer – Consumer problem
d) None of the mentioned

Answer: c
Clarification: None.

2. In the bounded buffer problem, there are the empty and full semaphores that ____________
a) count the number of empty and full buffers
b) count the number of empty and full memory spaces
c) count the number of empty and full queues
d) none of the mentioned

Answer: a
Clarification: None.

3. In the bounded buffer problem ____________
a) there is only one buffer
b) there are n buffers ( n being greater than one but finite)
c) there are infinite buffers
d) the buffer size is bounded

Answer: b
Clarification: None.

4. To ensure difficulties do not arise in the readers – writers problem _______ are given exclusive access to the shared object.
a) readers
b) writers
c) readers and writers
d) none of the mentioned

Answer: b
Clarification: None.

5. The dining – philosophers problem will occur in case of ____________
a) 5 philosophers and 5 chopsticks
b) 4 philosophers and 5 chopsticks
c) 3 philosophers and 5 chopsticks
d) 6 philosophers and 5 chopsticks

Answer: a
Clarification: None.

6. A deadlock free solution to the dining philosophers problem ____________
a) necessarily eliminates the possibility of starvation
b) does not necessarily eliminate the possibility of starvation
c) eliminates any possibility of any kind of problem further
d) none of the mentioned

Answer: b
Clarification: None.

7. All processes share a semaphore variable mutex, initialized to 1. Each process must execute wait(mutex) before entering the critical section and signal(mutex) afterward.
Suppose a process executes in the following manner.

signal(mutex);
.....
critical section
.....
wait(mutex);

In this situation :
a) a deadlock will occur
b) processes will starve to enter critical section
c) several processes maybe executing in their critical section
d) all of the mentioned

Answer: c
Clarification: None.

8. All processes share a semaphore variable mutex, initialized to 1. Each process must execute wait(mutex) before entering the critical section and signal(mutex) afterward.
Suppose a process executes in the following manner.

wait(mutex);
.....
critical section
.....
wait(mutex);

a) a deadlock will occur
b) processes will starve to enter critical section
c) several processes maybe executing in their critical section
d) all of the mentioned

Answer: a
Clarification: None.

9. Consider the methods used by processes P1 and P2 for accessing their critical sections whenever needed, as given below. The initial values of shared boolean variables S1 and S2 are randomly assigned. (GATE 2010)

Method used by P1 :
while(S1==S2);
Critical section
S1 = S2;
 
Method used by P2 :
while(S1!=S2);
Critical section
S2 = not(S1);

Which of the following statements describes properties achieved?
a) Mutual exclusion but not progress
b) Progress but not mutual exclusion
c) Neither mutual exclusion nor progress
d) Both mutual exclusion and progress

Answer: d

Operating System MCQs on “I/O System – Application I/O Interface”

1. If one or more devices use a common set of wires to communicate with the computer system, the connection is called ______
a) CPU
b) Monitor
c) Wirefull
d) Bus

Answer: d
Clarification: None.

2. A ____ a set of wires and a rigidly defined protocol that specifies a set of messages that can be sent on the wires.
a) port
b) node
c) bus
d) none of the mentioned

Answer: c
Clarification: None.

3. When device A has a cable that plugs into device B, and device B has a cable that plugs into device C and device C plugs into a port on the computer, this arrangement is called a _________
a) port
b) daisy chain
c) bus
d) cable

Answer: b
Clarification: None.

4. The _________ present a uniform device-access interface to the I/O subsystem, much as system calls provide a standard interface between the application and the operating system.
a) Devices
b) Buses
c) Device drivers
d) I/O systems

Answer: c
Clarification: None.

5. A ________ is a collection of electronics that can operate a port, a bus, or a device.
a) controller
b) driver
c) host
d) bus

Answer: a
Clarification: None.

6. An I/O port typically consists of four registers status, control, ________ and ________ registers.
a) system in, system out
b) data in, data out
c) flow in, flow out
d) input, output

Answer: b
Clarification: None.

7. The ______ register is read by the host to get input.
a) flow in
b) flow out
c) data in
d) data out

Answer: c
Clarification: None.

8. The ______ register is written by the host to send output.
a) status
b) control
c) data in
d) data out

Answer: d
Clarification: None.

9. The hardware mechanism that allows a device to notify the CPU is called _______
a) polling
b) interrupt
c) driver
d) controlling

Answer: b
Clarification: None.

10. The CPU hardware has a wire called __________ that the CPU senses after executing every instruction.
a) interrupt request line
b) interrupt bus
c) interrupt receive line
d) interrupt sense line

Answer: a
Clarification: None.

11. The _________ determines the cause of the interrupt, performs the necessary processing and executes a return from the interrupt instruction to return the CPU to the execution state prior to the interrupt.
a) interrupt request line
b) device driver
c) interrupt handler
d) all of the mentioned

Answer: c
Clarification: None.

12. In general the two interrupt request lines are ____________
a) maskable & non maskable interrupts
b) blocked & non maskable interrupts
c) maskable & blocked interrupts
d) none of the mentioned

Answer: a
Clarification: None.

13. The _________ are reserved for events such as unrecoverable memory errors.
a) non maskable interrupts
b) blocked interrupts
c) maskable interrupts
d) none of the mentioned

Answer: a

Operating System Multiple Choice Questions on “Security – Securing Systems and Facilities”.

1. What is not an important part of security protection?
a) Large amount of RAM to support antivirus
b) Strong passwords
c) Audit log periodically
d) Scan for unauthorized programs in system directories

Answer: a
Clarification: RAM has no effect on security of a system. System’s protection remains unchanged in increasing or decreasing amount of RAM.

2. What is used to protect network from outside internet access?
a) A trusted antivirus
b) 24 hours scanning for virus
c) Firewall to separate trusted and untrusted network
d) Deny users access to websites which can potentially cause security leak

Answer: c
Clarification: Firewall create a protective barrier to secure internal network. An antivirus can only detect harmful viruses but cannot stop illegal access by remote attacker.

3. What is the best practice in the firewall domain environment?
a) Create two domain trusted and untrusted domain
b) Create strong policy in firewall to support different types of users
c) Create a Demilitarized zone
d) Create two DMZ zones with one untrusted domain

Answer: c
Clarification: All live servers or workstations are kept in a separate zone than inside and outside to enhance protection.

4. Which direction access cannot happen using DMZ zone by default?
a) Company computer to DMZ
b) Internet to DMZ
c) Internet to company computer
d) Company computer to internet

Answer: c
Clarification: Connection from internet is never allowed to directly access internal PCs but is routed through DMZ zone to prevent attacks.

5. What are the two features of a tripwire file system?
a) It is a tool to monitor file systems
b) It is used to automatically take corrective action
c) It is used to secure UNIX system
d) None of the mentioned

Answer: a
Clarification: None.

6. How do viruses avoid basic pattern match of antivirus?
a) They are encrypted
b) They act with special permissions
c) They modify themselves
d) None of the mentioned

Answer: c
Clarification: None.

7. How does an antivirus of today identify viruses?
a) Previously known patterns
b) It can detect unknown patterns
c) It can take high priority to increase scanning speed
d) None of the mentioned

Answer: a
Clarification: None.

8. What is known as a sandbox?
a) It is a program which can be molded to do the desired task
b) It is a program that is controlled or emulated section of OS
c) It is a special mode of antivirus
d) None of the mentioned

Answer: b
Clarification: None.

9. What is are two safe computing practices?
a) Not to open software from unknown vendors
b) Open and execute programs in admin level/root
c) Open and execute programs in presence of antivirus
d) None of the mentioned

Answer: a
Clarification: Disgruntled employees have in past infected the master copies of software programs to do economic harm to the company.

Operating System Multiple Choice Questions & Answers on “Virtual Memory – Allocation of Frames”.

1. The minimum number of frames to be allocated to a process is decided by the ____________
a) the amount of available physical memory
b) operating System
c) instruction set architecture
d) none of the mentioned

Answer: c
Clarification: None.

2. When a page fault occurs before an executing instruction is complete if ____________
a) the instruction must be restarted
b) the instruction must be ignored
c) the instruction must be completed ignoring the page fault
d) none of the mentioned

Answer: a
Clarification: None.

3. Consider a machine in which all memory reference instructions have only one memory address, for them we need at least _____ frame(s).
a) one
b) two
c) three
d) none of the mentioned

Answer: b
Clarification: At least one frame for the instruction and one for the memory reference.

4. The maximum number of frames per process is defined by ____________
a) the amount of available physical memory
b) operating System
c) instruction set architecture
d) none of the mentioned

Answer: a
Clarification: None.

5. The algorithm in which we split m frames among n processes, to give everyone an equal share, m/n frames is known as ____________
a) proportional allocation algorithm
b) equal allocation algorithm
c) split allocation algorithm
d) none of the mentioned

Answer: b
Clarification: None.

6. The algorithm in which we allocate memory to each process according to its size is known as ____________
a) proportional allocation algorithm
b) equal allocation algorithm
c) split allocation algorithm
d) none of the mentioned

Answer: a
Clarification: None.

7. With either equal or proportional algorithm, a high priority process is treated ___________ a low priority process.
a) greater than
b) same as
c) lesser than
d) none of the mentioned

Answer: b
Clarification: None.

8. _________ replacement allows a process to select a replacement frame from the set of all frames, even if the frame is currently allocated to some other process.
a) Local
b) Universal
c) Global
d) Public

Answer: c
Clarification: None.

9. _________ replacement allows each process to only select from its own set of allocated frames.
a) Local
b) Universal
c) Global
d) Public

Answer: a
Clarification: None.

10. One problem with the global replacement algorithm is that ____________
a) it is very expensive
b) many frames can be allocated to a process
c) only a few frames can be allocated to a process
d) a process cannot control its own page – fault rate

Answer: d
Clarification: None.

11. ________ replacement generally results in greater system throughput.
a) Local
b) Global
c) Universal
d) Public

Answer: b