Category: Operating System Objective Questions

Operating System Multiple Choice Questions on “Protection – Memory Protection”.

1. What is true regarding ‘Fence’?
a) Its a method to confine users to one side of a boundary
b) It can protect Operating system from one user
c) It cannot protect users from each other
d) All of the mentioned

Answer: d
Clarification: None.

2. What is not true regarding ‘Fence’?
a) It is implemented via hardware register
b) It doesn’t protect users from each other
c) It good to protect OS from abusive users
d) Its implementation is unrestricted and can take any amount of space in Operating system.

Answer: d
Clarification: None.

3. What is correct regarding ‘relocation’ w.r.t protecting memory?
a) It is a process of taking a program as if it began at address 0
b) It is a process of taking a program as if it began at address 0A
c) Fence cannot be used within relocation process
d) All of the mentioned

Answer: a
Clarification: None.

4. How can fence and relocation be used together?
a) To each program address, the contents of fence register are added
b) To contents of fence register is subtracted from actual address of program
c) To each program address, the contents of fence register are not added
d) None of the mentioned

Answer: a
Clarification: This both relocates the address and guarantees that no one can access a location lower than a fence address.

5. What is the basic need in protecting memory in multi-user environment?
a) We need two registers one ‘start’ and other ‘end’
b) We need a variable register
c) A fence register has to be used known as base register.
d) None of the mentioned

Answer: c
Clarification: None.

6. What is the role of base/bound registers?
a) They give starting address to a program
b) Program’s addresses are neatly confined to space between the base and the bound registers
c) They provide encrypted environment
d) This technique doesn’t protects a program’s address from modification by another user

Answer: b
Clarification: None.

7. What is all-or-nothing situation for sharing in memory?
a) Program makes all its data available to be accessed
b) It prohibits access to some
c) It creates rules who can access program memory
d) It separates program memory and data memory

Answer: a
Clarification: None.

8. How is disadvantage of all-or-nothing approach overcome?
a) Base/Bound
b) Relocation technique
c) Fence method
d) Tagged architecture

Answer: d
Clarification: None.

9. What is true regarding tagged architecture?
a) Every word of machine memory has one or more extra bits
b) Extra bits are used to do padding
c) Extra bits are not used to identify rights to that word
d) It is very compatible to code upgrades

Answer: a
Clarification: None.

10. What is best solution to have effect of unbounded number if base/bound registers?
a) Tagged architecture
b) Segmentation
c) Fence method
d) None of the mentioned

Answer: b
Clarification: None.

11. What is a major feature of segmentation?
a) Program is divided in data memory and program memory
b) Program is executed in segments
c) Program is divided into pieces having different access rights
d) It has effect of an unbounded architecture

Answer: c
Clarification: None.

12. What is the correct way the segmentation program address is stored?
a) name, offset
b) start, stop
c) access, rights
d) offset, rights

Answer: a
Clarification: OS can retrieve the real address via looking for the table then making a simple calculation: address of the name + offset.

13. What is the main objective of protection?
a) Ensure all objects are protected individually
b) Objects have different priority and thus different levels of protection
c) Ensure that each object is accessed correctly and only by allowed processes
d) None of the mentioned

Answer: c
Clarification: None.

14. What is the principle of least privilege?
a) Less privileges provide difficulty in executing admin tasks
b) Users can get temporary high privilege access
c) Users should be given just enough privileges to perform their tasks
d) None of the mentioned

Answer: c
Clarification: None.

15. What is the need of protection?
a) Prevent mischievous violation
b) Prevent and intentional
c) Ensure that each program component uses resources allotted to it only
d) All of the mentioned

Answer: d
Clarification: None.

Operating System Multiple Choice Questions on “The Critical Section (CS) Problem and Solutions”.

1. Concurrent access to shared data may result in ____________
a) data consistency
b) data insecurity
c) data inconsistency
d) none of the mentioned

Answer: c
Clarification: None.

2. A situation where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called ____________
a) data consistency
b) race condition
c) aging
d) starvation

Answer: b
Clarification: None.

3. The segment of code in which the process may change common variables, update tables, write into files is known as ____________
a) program
b) critical section
c) non – critical section
d) synchronizing

Answer: b
Clarification: None.

4. Which of the following conditions must be satisfied to solve the critical section problem?
a) Mutual Exclusion
b) Progress
c) Bounded Waiting
d) All of the mentioned

Answer: d
Clarification: None.

5. Mutual exclusion implies that ____________
a) if a process is executing in its critical section, then no other process must be executing in their critical sections
b) if a process is executing in its critical section, then other processes must be executing in their critical sections
c) if a process is executing in its critical section, then all the resources of the system must be blocked until it finishes execution
d) none of the mentioned

Answer: a
Clarification: None.

6. Bounded waiting implies that there exists a bound on the number of times a process is allowed to enter its critical section ____________
a) after a process has made a request to enter its critical section and before the request is granted
b) when another process is in its critical section
c) before a process has made a request to enter its critical section
d) none of the mentioned

Answer: a
Clarification: None.

7. A minimum of _____ variable(s) is/are required to be shared between processes to solve the critical section problem.
a) one
b) two
c) three
d) four

Answer: b
Clarification: None.

8. In the bakery algorithm to solve the critical section problem ____________
a) each process is put into a queue and picked up in an ordered manner
b) each process receives a number (may or may not be unique) and the one with the lowest number is served next
c) each process gets a unique number and the one with the highest number is served next
d) each process gets a unique number and the one with the lowest number is served next

Answer: b

Operating System Multiple Choice Questions on “Paging”.

1. Physical memory is broken into fixed-sized blocks called ________
a) frames
b) pages
c) backing store
d) none of the mentioned

Answer: a
Clarification: None.

2. Logical memory is broken into blocks of the same size called _________
a) frames
b) pages
c) backing store
d) none of the mentioned

Answer: b
Clarification: None.

3. Every address generated by the CPU is divided into two parts. They are ____________
a) frame bit & page number
b) page number & page offset
c) page offset & frame bit
d) frame offset & page offset

Answer: b
Clarification: None.

4. The __________ is used as an index into the page table.
a) frame bit
b) page number
c) page offset
d) frame offset

Answer: b
Clarification: None.

5. The _____ table contains the base address of each page in physical memory.
a) process
b) memory
c) page
d) frame

Answer: c
Clarification: None.

6. The size of a page is typically ____________
a) varied
b) power of 2
c) power of 4
d) none of the mentioned

Answer: b
Clarification: None.

7. If the size of logical address space is 2 to the power of m, and a page size is 2 to the power of n addressing units, then the high order _____ bits of a logical address designate the page number, and the ____ low order bits designate the page offset.
a) m, n
b) n, m
c) m – n, m
d) m – n, n

Answer: d
Clarification: None.

8. With paging there is no ________ fragmentation.
a) internal
b) external
c) either type of
d) none of the mentioned

Answer: b
Clarification: None.

9. The operating system maintains a ______ table that keeps track of how many frames have been allocated, how many are there, and how many are available.
a) page
b) mapping
c) frame
d) memory

Answer: c
Clarification: None.

10. Paging increases the ______ time.
a) waiting
b) execution
c) context – switch
d) all of the mentioned

Answer: c
Clarification: None.

11. Smaller page tables are implemented as a set of _______
a) queues
b) stacks
c) counters
d) registers

Answer: d
Clarification: None.

12. The page table registers should be built with _______
a) very low speed logic
b) very high speed logic
c) a large memory space
d) none of the mentioned

Answer: b
Clarification: None.

13. For larger page tables, they are kept in main memory and a __________ points to the page table.
a) page table base register
b) page table base pointer
c) page table register pointer
d) page table base

Answer: a
Clarification: None.

14. For every process there is a __________
a) page table
b) copy of page table
c) pointer to page table
d) all of the mentioned

Answer: a
Clarification: None.

15. Time taken in memory access through PTBR is ____________
a) extended by a factor of 3
b) extended by a factor of 2
c) slowed by a factor of 3
d) slowed by a factor of 2

Answer: d

Operating System Questions and Answers on “Multimedia System – Network Management” and will also be useful for campus interviews.

1. The three general methods for delivering content from a server to a client across a network are ___________
a) unicasting
b) multicasting
c) broadcasting
d) all of the mentioned

Answer: d
Clarification: None.

2. Unicasting delivers the content to ___________
a) a single client
b) all clients, regardless whether they want the content or not
c) a group of receivers who indicate they wish to receive the content
d) none of the mentioned

Answer: a
Clarification: None.

3. Broadcasting delivers the content to ___________
a) a single client
b) all clients, regardless whether they want the content or not
c) a group of receivers who indicate they wish to receive the content
d) none of the mentioned

Answer: b
Clarification: None.

4. Multicasting delivers the content to ___________
a) a single client
b) all clients, regardless whether they want the content or not
c) a group of receivers who indicate they wish to receive the content
d) none of the mentioned

Answer: c
Clarification: None.

5. RTSP stands for ___________
a) Real Time Streaming Policy
b) Real Time Streaming Protocol
c) Real Time Systems Protocol
d) Read Time Streaming Policy

Answer: b
Clarification: None.

6. HTTP is __________
a) a stateful protocol
b) a stateless protocol
c) a protocol that maintains the status of its connection with the client
d) a stateless protocol that does not maintain the status of its connection with the client

Answer: d
Clarification: None.

7. RTSP includes which of the following states?
a) SETUP
b) PLAY
c) PAUSE
d) All of the mentioned

Answer: d
Clarification: None.

8. In the SETUP state ___________
a) the server is setup
b) the client is setup
c) the server allocates resources for the client session
d) the client sends requests to the server

Answer: c
Clarification: None.

9. In the TEARDOWN state ___________
a) the server breaks down the connection and releases the resources allocated for the session
b) the client breaks down the connection and releases the resources allocated for the session
c) the system crashes
d) none of the mentioned

Answer: a
Clarification: None.

10. RTP stands for ___________
a) real time protocol
b) real time transmission control protocol
c) real time transmission protocol
d) real time transport protocol

Answer: d
Clarification: None.

11. The problem with unicast delivery is that the ___________
a) memory allocation is difficult
b) server must establish a separate unicast session for each client
c) the routers must support unicasting
d) the clients must be close to the server

Answer: b
Clarification: None.

12. The difficulty with multicasting from a practical point of view is ___________
a) memory allocation is difficult
b) server must establish a separate unicast session for each client
c) the routers must support multicasting
d) none of the mentioned

Answer: c
Clarification: None.

13. To let a client have random access to a media stream with ___________
a) the protocol used must not be stateless
b) the server must support download
c) the stream should give access rights to the client
d) all of the mentioned

Answer: a

Operating System Multiple Choice Questions on “Virtual Memory – Demand Paging”.

1. Virtual memory allows ____________
a) execution of a process that may not be completely in memory
b) a program to be smaller than the physical memory
c) a program to be larger than the secondary storage
d) execution of a process without being in physical memory

Answer: a

2. The instruction being executed, must be in ____________
a) physical memory
b) logical memory
c) physical & logical memory
d) none of the mentioned

Answer: a

3. Error handler codes, to handle unusual errors are ____________
a) almost never executed
b) executed very often
c) executed periodically
d) none of the mentioned

Answer: a

4. The ability to execute a program that is only partially in memory has benefits like ____________
a) The amount of physical memory cannot put a constraint on the program
b) Programs for an extremely large virtual space can be created
c) Throughput increases
d) All of the mentioned

Answer: d

5. In virtual memory. the programmer __________ of overlays.
a) has to take care
b) does not have to take care
c) all of the mentioned
d) none of the mentioned

Answer: b

6. Virtual memory is normally implemented by ________
a) demand paging
b) buses
c) virtualization
d) all of the mentioned

Answer: a
Clarification: None.

7. Segment replacement algorithms are more complex than page replacement algorithms because ____________
a) Segments are better than pages
b) Pages are better than segments
c) Segments have variable sizes
d) Segments have fixed sizes

Answer: c
Clarification: None.

8. A swapper manipulates ___________ whereas the pager is concerned with individual _______ of a process.
a) the entire process, parts
b) all the pages of a process, segments
c) the entire process, pages
d) none of the mentioned

Answer: c
Clarification: None.

9. Using a pager ____________
a) increases the swap time
b) decreases the swap time
c) decreases the swap time & amount of physical memory needed
d) increases the amount of physical memory needed

Answer: c
Clarification: None.

10. The valid – invalid bit, in this case, when valid indicates?
a) the page is not legal
b) the page is illegal
c) the page is in memory
d) the page is not in memory

Answer: c
Clarification: None.

11. A page fault occurs when?
a) a page gives inconsistent data
b) a page cannot be accessed due to its absence from memory
c) a page is invisible
d) all of the mentioned

Answer: b
Clarification: None.

12. When a page fault occurs, the state of the interrupted process is ____________
a) disrupted
b) invalid
c) saved
d) none of the mentioned

Answer: c
Clarification: None.

13. When a process begins execution with no pages in memory?
a) process execution becomes impossible
b) a page fault occurs for every page brought into memory
c) process causes system crash
d) none of the mentioned

Answer: b
Clarification: None.

14. If the memory access time is denoted by ‘ma’ and ‘p’ is the probability of a page fault (0 <= p <= 1). Then the effective access time for a demand paged memory is ____________
a) p x ma + (1-p) x page fault time
b) ma + page fault time
c) (1-p) x ma + p x page fault time
d) none of the mentioned

Answer: c
Clarification: None.

15. When the page fault rate is low ____________
a) the turnaround time increases
b) the effective access time increases
c) the effective access time decreases
d) turnaround time & effective access time increases

Answer: c
Clarification: None.

16. Locality of reference implies that the page reference being made by a process ____________
a) will always be to the page used in the previous page reference
b) is likely to be one of the pages used in the last few page references
c) will always be one of the pages existing in memory
d) will always lead to page faults

Answer: b

Operating System Multiple Choice Questions on “File System Implementation – Performance”.

1. _______ tend to represent a major bottleneck in system performance.
a) CPUs
b) Disks
c) Programs
d) I/O

Answer: b

2. In UNIX, even an ’empty’ disk has a percentage of its space lost to ______
a) programs
b) inodes
c) virtual memory
d) stacks

Answer: b

3. By preallocating the inodes and spreading them across the volume, we ___________ the system performance.
a) improve
b) decrease
c) maintain
d) do not affect

Answer: a

4. ____________ writes occur in the order in which the disk subsystem receives them, and the writes are not buffered.
a) Asynchronous
b) Regular
c) Synchronous
d) Irregular

Answer: c

5. In ___________ writes, the data is stored in the cache.
a) Asynchronous
b) Regular
c) Synchronous
d) Irregular

Answer: a

6. A file being read or written sequentially should not have its pages replaced in LRU order, because _____________
a) it is very costly
b) the most recently used page will be used last
c) it is not efficient
d) all of the mentioned

Answer: b
Clarification: None.

7. In the optimized technique for sequential access ___________ removes a page from the buffer as soon as the next page is requested.
a) write ahead
b) read ahead
c) free-behind
d) add-front

Answer: c
Clarification: None.

8. With _______ a requested page and several subsequent pages are read and cached.
a) write ahead
b) read ahead
c) free-behind
d) add-front

Answer: b