Operating System MCQ Set 1
1. Each entry in a Translation look-aside buffer (TLB) consists of :
a) key
b) value
c) bit value
d) constant
Answer
Answer: a [Reason:] None.
2. If a page number is not found in the TLB, then it is known as a :
a) TLB miss
b) Buffer miss
c) TLB hit
d) All of the mentioned
Answer
Answer: a [Reason:] None.
3. An ______ uniquely identifies processes and is used to provide address space protection for that process.
a) address space locator
b) address space identifier
c) address process identifier
d) None of the mentioned
Answer
Answer: b [Reason:] None.
4. The percentage of times a page number is found in the TLB is known as :
a) miss ratio
b) hit ratio
c) miss percent
d) None of the mentioned
Answer
Answer: b [Reason:] None.
5. Memory protection in a paged environment is accomplished by :
a) protection algorithm with each page
b) restricted access rights to users
c) restriction on page visibility
d) protection bit with each page
Answer
Answer: d [Reason:] None.
6. When the valid – invalid bit is set to valid, it means that the associated page :
a) is in the TLB
b) has data in it
c) is in the process’s logical address space
d) is the system’s physical address space
Answer
Answer: c [Reason:] None.
7. Illegal addresses are trapped using the _____ bit.
a) error
b) protection
c) valid – invalid
d) access
Answer
Answer: c [Reason:] None.
8. When there is a large logical address space, the best way of paging would be :
a) not to page
b) a two level paging algorithm
c) the page table itself
d) all of the mentioned
Answer
Answer: b [Reason:] None.
9. In a paged memory, the page hit ratio is 0.35. The required to access a page in secondary memory is equal to 100 ns. The time required to access a page in primary memory is 10 ns. The average time required to access a page is :
a) 3.0 ns
b) 68.0 ns
c) 68.5 ns
d) 78.5 ns
Answer
Answer: c [Reason:] None.
10. To obtain better memory utilization, dynamic loading is used. With dynamic loading, a routine is not loaded until it is called. For implementing dynamic loading,
a) special support from hardware is required
b) special support from operating system is essential
c) special support from both hardware and operating system is essential
d) user programs can implement dynamic loading without any special support from hardware or operating system
Answer
Answer: d [Reason:] None.
11. In paged memory systems, if the page size is increased, then the internal fragmentation generally :
a) becomes less
b) becomes more
c) remains constant
d) none of the mentioned
Answer
Answer: b [Reason:] None.
Operating System MCQ Set 2
1. In segmentation, each address is specified by :
a) a segment number & offset
b) an offset & value
c) a value & segment number
d) a key & value
Answer
Answer: a [Reason:] None.
2. In paging the user provides only ________ which is partitioned by the hardware into ________ and ______
a) one address, page number, offset
b) one offset, page number, address
c) page number, offset, address
d) none of the mentioned
Answer
Answer: a [Reason:] None.
3. Each entry in a segment table has a :
a) segment base
b) segment peak
c) segment value
d) none of the mentioned
Answer
Answer: a [Reason:] None.
4. The segment base contains the :
a) starting logical address of the process
b) starting physical address of the segment in memory
c) segment length
d) none of the mentioned
Answer
Answer: b [Reason:] None.
5. The segment limit contains the :
a) starting logical address of the process
b) starting physical address of the segment in memory
c) segment length
d) none of the mentioned
Answer
Answer: c [Reason:] None.
6. The offset ‘d’ of the logical address must be :
a) greater than segment limit
b) between 0 and segment limit
c) between 0 and the segment number
d) greater than the segment number
Answer
Answer: b [Reason:] None.
7. If the offset is legal :
a) it is used as a physical memory address itself
b) it is subtracted from the segment base to produce the physical memory address
c) it is added to the segment base to produce the physical memory address
d) none of the mentioned
Answer
Answer: a [Reason:] None.
8. When the entries in the segment tables of two different processes point to the same physical location :
a) the segments are invalid
b) the processes get blocked
c) segments are shared
d) all of the mentioned
Answer
Answer: c [Reason:] None.
9. The protection bit is 0/1 based on :
a) write only
b) read only
c) read – write
d) none of the mentioned
Answer
Answer: c [Reason:] None.
10. If there are 32 segments, each of size 1Kb, then the logical address should have :
a) 13 bits
b) 14 bits
c) 15 bits
d) 16 bits
Answer
Answer: a [Reason:] To specify a particular segment, 5 bits are required. To select a particular byte after selecting a page, 10 more bits are required. Hence 15 bits are required.
11. Consider a computer with 8 Mbytes of main memory and a 128 K cache. The cache block size is 4 K. It uses a direct mapping scheme for cache management. How many different main memory blocks can map onto a given physical cache block ?
a) 2048
b) 256
c) 64
d) 8
Answer
Answer: c [Reason:] None.
12. A multilevel page table is preferred in comparison to a single level page table for translating virtual address to physical address because :
a) it reduces the memory access time to read or write a memory location
b) it helps to reduce the size of page table needed to implement the virtual address space of a process
c) it is required by the translation look aside buffer
d) it helps to reduce the number of page faults in page replacement algorithms
Answer
Answer: b [Reason:] None.
Operating System MCQ Set 3
1. Address Binding is :
a) going to an address in memory
b) locating an address with the help of another address
c) binding two addresses together to form a new address in a different memory space
d) a mapping from one address space to another
Answer
Answer: d [Reason:] None.
2. Binding of instructions and data to memory addresses can be done at :
a) Compile time
b) Load time
c) Execution time
d) All of the mentioned
Answer
Answer: d [Reason:] None.
3. If the process can be moved during its execution from one memory segment to another, then binding must be :
a) delayed until run time
b) preponed to compile time
c) preponed to load time
d) none of the mentioned
Answer
Answer: a [Reason:] None.
4. Dynamic loading is :
a) loading multiple routines dynamically
b) loading a routine only when it is called
c) loading multiple routines randomly
d) none of the mentioned
Answer
Answer: b [Reason:] None.
5. The advantage of dynamic loading is that :
a) A used routine is used multiple times
b) An unused routine is never loaded
c) CPU utilization increases
d) All of the mentioned
Answer
Answer: b [Reason:] None.
6. The idea of overlays is to :
a) data that are needed at any given time
b) enable a process to be larger than the amount of memory allocated to it
c) keep in memory only those instructions
d) all of the mentioned
Answer
Answer: d [Reason:] None.
7. The _____ must design and program the overlay structure.
a) programmer
b) system architect
c) system designer
d) none of the mentioned
Answer
Answer: a [Reason:] None.
8. The _____ swaps processes in and out of the memory.
a) Memory manager
b) CPU
c) CPU manager
d) User
Answer
Answer: a [Reason:] None.
9. If a higher priority process arrives and wants service, the memory manager can swap out the lower priority process to execute the higher priority process. When the higher priority process finishes, the lower priority process is swapped back in and continues execution. This variant of swapping is sometimes called :
a) priority swapping
b) pull out, push in
c) roll out, roll in
d) none of the mentioned
Answer
Answer: c [Reason:] None.
10. If binding is done at assembly or load time, then the process _____ be moved to different locations after being swapped out and in again.
a) can
b) must
c) can never
d) may
Answer
Answer: c [Reason:] None.
11. In a system that does not support swapping,
a) the compiler normally binds symbolic addresses (variables) to relocatable addresses
b) the compiler normally binds symbolic addresses to physical addresses
c) the loader binds relocatable addresses to physical addresses
d) binding of symbolic addresses to physical addresses normally takes place during execution
Answer
Answer: a [Reason:] None.
12. Which of the following is TRUE ?
a) Overlays are used to increase the size of physical memory
b) Overlays are used to increase the logical address space
c) When overlays are used, the size of a process is not limited to the size of the physical memory
d) Overlays are used whenever the physical address space is smaller than the logical address space
Answer
Answer: c [Reason:] None.
Operating System MCQ Set 4
1. The address generated by the CPU is referred to as :
a) Physical address
b) Logical address
c) Neither physical nor logical
d) None of the mentioned
Answer
Answer: b [Reason:] None.
2. The address loaded into the memory address register of the memory is referred to as :
a) Physical address
b) Logical address
c) Neither physical nor logical
d) None of the mentioned
Answer
Answer: a [Reason:] None.
3. The run time mapping from virtual to physical addresses is done by a hardware device called the :
a) Virtual to physical mapper
b) Memory management unit
c) Memory mapping unit
d) None of the mentioned
Answer
Answer: b [Reason:] None.
4. The base register is also known as the :
a) basic register
b) regular register
c) relocation register
d) delocation register
Answer
Answer: c [Reason:] None.
5. The size of a process is limited to the size of :
a) physical memory
b) external storage
c) secondary storage
d) none of the mentioned
Answer
Answer: a [Reason:] None.
6. If execution time binding is being used, then a process ______ be swapped to a different memory space.
a) has to be
b) can never
c) must
d) may
Answer
Answer: d [Reason:] None.
7. Swapping requires a ___
a) motherboard
b) keyboard
c) monitor
d) backing store
Answer
Answer: d [Reason:] None.
8. The backing store is generally a :
a) fast disk
b) disk large enough to accommodate copies of all memory images for all users
c) disk to provide direct access to the memory images
d) all of the mentioned
Answer
Answer: d [Reason:] None.
9. The ________ consists of all processes whose memory images are in the backing store or in memory and are ready to run.
a) wait queue
b) ready queue
c) cpu
d) secondary storage
Answer
Answer: b [Reason:] None.
10. The ___ time in a swap out of a running process and swap in of a new process into the memory is very high.
a) context – switch
b) waiting
c) execution
d) all of the mentioned
Answer
Answer: a [Reason:] None.
11. The major part of swap time is _______ time.
a) waiting
b) transfer
c) execution
d) none of the mentioned
Answer
Answer: b [Reason:] None.
12. Swapping _______ be done when a process has pending I/O, or has to execute I/O operations only into operating system buffers.
a) must
b) can
c) must never
d) maybe
Answer
Answer: c [Reason:] None.
13. Swap space is allocated :
a) as a chunk of disk
b) separate from a file system
c) into a file system
d) all of the mentioned
Answer
Answer: a [Reason:] None.
Operating System MCQ Set 5
1. The model in which one kernel thread is mapped to many user-level threads is called :
a) Many to One model
b) One to Many model
c) Many to Many model
d) One to One model
Answer
Answer: a [Reason:] None.
2. The model in which one user-level thread is mapped to many kernel level threads is called :
a) Many to One model
b) One to Many model
c) Many to Many model
d) One to One model
Answer
Answer: b [Reason:] None.
3. In the Many to One model, if a thread makes a blocking system call :
a) the entire process will be blocked
b) a part of the process will stay blocked, with the rest running
c) the entire process will run
d) none of the mentioned
Answer
Answer: a [Reason:] None.
4. In the Many to One model, multiple threads are unable to run in parallel on multiprocessors because :
a) only one thread can access the kernel at a time
b) many user threads have access to just one kernel thread
c) there is only one kernel thread
d) none of the mentioned
Answer
Answer: a [Reason:] None.
5. The One to One model allows :
a) increased concurrency
b) decreased concurrency
c) increased or decreased concurrency
d) concurrency equivalent to other models
Answer
Answer: a [Reason:] None.
6. In the One to One model when a thread makes a blocking system call :
a) other threads are strictly prohibited from running
b) other threads are allowed to run
c) other threads only from other processes are allowed to run
d) none of the mentioned
Answer
Answer: b [Reason:] None.
7. Which of the following is the drawback of the One to One Model ?
a) increased concurrency provided by this model
b) decreased concurrency provided by this model
c) creating so many threads at once can crash the system
d) creating a user thread requires creating the corresponding kernel thread
Answer
Answer: d [Reason:] None.
8. When is the Many to One model at an advantage ?
a) When the program does not need multi-threading
b) When the program has to be multi-threaded
c) When there is a single processor
d) None of the mentioned
Answer
Answer: a [Reason:] None.
9. In the Many to Many model true concurrency cannot be gained because :
a) the kernel can schedule only one thread at a time
b) there are too many threads to handle
c) it is hard to map threads with each other
d) none of the mentioned
Answer
Answer: a [Reason:] None.
10. In the Many to Many model when a thread performs a blocking system call :
a) other threads are strictly prohibited from running
b) other threads are allowed to run
c) other threads only from other processes are allowed to run
d) none of the mentioned
Answer
Answer: b [Reason:] None.
