Operating System Memory Management Solved MCQs

 Operating System Memory Management Solved MCQs

In this section of Operating System Main Memory – Memory Management.it contain Operating System Main Memory – Memory Management MCQs (Multiple Choice Questions Answers).All the MCQs (Multiple Choice Question Answers) requires in detail reading of Operating System subject as the hardness level of MCQs have been kept to advance level.

 

1.Memory hierarchy comprises of Disk ,RAM Memory,Caches,select the increasing order of their access time by CPU for an instruction or data

• Disk ,RAM , Caches
• RAM,Disk,Caches
• Caches,RAM,Disk
• RAM,Caches,Disk

C. Caches,RAM,Disk

2.for which of the below allocation is managed by Kernel and use of the allocated memory is managed by run time library?

• Caches
• RAM
• Disk
• All of the above

B. RAM

3.for which of the below allocation and use is managed entirely in the hardware?

• Caches
• RAM
• Disk
• All of the above

A. Caches

4.for which of the below allocation and use is managed by kernel?

• Caches
• RAM
• Disk
• All of the above

C. Disk

5.for which of the below memory Accommodating more process in memory and  ensuring high hit ratio is the main performance issue

• Caches
• RAM
• Disk
• All of the above

B. RAM

6.for which of the below memory ensuring high hit ratio is the main performance issue

• Caches
• RAM
• Disk
• All of the above

A. Caches

7.for which of the below memory Quick loading and storing of parts of process address spaces is the main perfomanace issue

• Caches
• RAM
• Disk
• All of the above

C. Disk

8.The effective memory access time depends on a

• Miss Ratio
• Hit Ratio
• Bit Ratio
• Byte Ratio

B. Hit Ratio Explanation :

9.During operation, a process creates data structures within the memory already allocated to it by the kernel,This function is actually performed by the____

• Run time library
• dynamic library
• static library
• load time library

A. Run time library

10.The kernel may decide keeping part of each process's address spaces in memory.it is achieved by part of memory hierarchy called____

• Caches
• Disk
• RAM
• Virtual memory

D. Virtual memory

11.Virtual memory in memory hierarchy consists of

• Caches and RAM
• Caches and Disk
• RAM and Disk
• All of the above

C. RAM and Disk

 
 This MCQs section is mainly focused on below lists of topics

1. Managing Memory hierarchy.
2. Static and Dynamic Memory Allocation.
   1. Static Binding
   2. Dynamic Binding
3. Execution of programs.
   1. Compilation or assembly
   2. Linking
   3. Relocation
   4. Static and Dynamic relocation of program
4. Linking
   1. static and Dynamic Linking
   2. Self relocating program
   3. Reentrant Programs

 

1.Memory allocation and deallocation can be managed by________

• CPU
• MMU
• GPR
• None of the above

B. MMU Explanation :

2.Which of the below factor considered the most in management of memory

• Efficient use of memory
• speedy allocation of memory
• speedy deallocation of memory
• All of the above

D. All of the above

3.Which of the following statements stands true for Static memory allocation.

1. Static memory allocated can be performed by a compiler,linker or loader.
2. Static memory allocation to a process is possible only if size of its data structures are known before its execution begins.
3. static memory allocation is performed in a lazy manner during execution of program.
4. static memory is allocated to a function or a variable just before its is used for the first time.

• 1,2
• 2,3
• 3,4
• 1,4

A. 1,2 Explanation :

4.Which of the following statements stands true for Dynamic memory allocation.

1. Dynamic memory allocated can be performed by a compiler,linker or loader.
2. Dynamic memory allocation to a process is possible only if size of its data structures are known before its execution begins.
3. Dynamic memory allocation is performed in a lazy manner during execution of program.
4. Dynamic memory is allocated to a function or a variable just before its is used for the first time.

• 1,2
• 2,3
• 3,4
• 1,4

C. 3,4 Explanation :

5.In which of the following memory allocation memory is wasted if we overestimate the its size or process may not operate correctly if we underestimate its size

• Dynamic memory allocation
• Static memory allocation
• contiguous memory allocation
• None-Contiguous memory allocation

B. Static memory allocation

6.______memory allocation avoid problems of wastage of memory and  the problems of underestimating the memory size

• Dynamic memory allocation
• Static memory allocation
• contiguous memory allocation
• None-Contiguous memory allocation

A. Dynamic memory allocation Explanation :

7.__________memory allocation incurs the overhead of memory allocation actions performed during operation of a process.

• Dynamic
• Static
• contiguous
• None-Contiguous

A. Dynamic

8.___ is generally called a translator

• loader
• Linker
• Compiler or Assembler
• re-locator

C. Compiler or Assembler Explanation :

9.source program is converted to machine language of the computers by_________

• loader
• Linker
• relocator
• Compiler or Assembler

D. Compiler or Assembler

10.Program P may call other programs during its execution,eg functions from mathematical libraries ,these functions should be included in the program,and their start address should be used in the function call instruction in P. This Procedure is called __________

• loading
• Linking
• Compiling or Assembling
• relocation

B. Linking

11.some object module merged with program P may have conflicting translated time address.This conflict is resolved by changing the memory binding of the object modules;this action is called______

• linking of object module
• loading of object module
• Relocation of object module
• compiling of object module

C. Relocation of object module Explanation :

12.The relocation and linking functions are performed by program called______

• compiler
• linker
• loader
• relocator

B. linker Explanation :

13.A Binary program has to be loaded in memory for execution.This function is performed by the __________

• compiler
• linker
• loader
• relocator

C. loader

14.Which of the following statements stands TRUE for Static Relocation of programs?

1. static relocation is performed before execution of the programs begins.
2. static relocation is performed during execution of the programs .
3. static relocation can be performed by suspending a program's execution,carrying out the relocation procedures and then resuming its execution.
4. it would require information concerning the translated origin and address sensitive instructions to be available during the program execution.

• 1
• 1,2
• 1,2,3
• 1,2,3,4

A. 1 Explanation :

15.Which of the following statements stands TRUE for Dynamic Relocation of programs

1. Dynamic relocation is performed before execution of the programs begins.
2. Dynamic relocation is performed during execution of the programs .
3. Dynamic relocation can be performed by suspending a program's execution,carrying out the relocation procedures and then resuming its execution.
4. it would require information concerning the translated origin and address sensitive instructions to be available during the program execution.

• 1
• 1,2
• 2,3
• 2,3,4

D. 2,3,4 Explanation :

16.some computer architecture provide a __________ to simplify dynamic relocation.

• Base Register
• special register
• Relocation register
• PSW-Program Status word

C. Relocation register Explanation :

17.Which of the following statements stands true for Static linking?

1. the linker links all modules of a program before its execution begins.
2. The linker is invoked when an unresolved external reference is encountered during its execution.the linker resolves the external reference and resumes execution of the program.
3. if several programs use the same module from a library,each program will get a private copy of the module;several copies of the module might present in a memory at the same time if program using the same module.
4. All of the above.

• 1 only
• 1,2 only
• 1,3 only
• 4

C. 1,3 only Explanation :

18.Which of the following statements stands true for Dynamic linking?

1. linking is performed during execution of a binary program.
2. if the module referenced by the program has already been linked to another program that is execution,the same copy of the module could be linked to this program as well,thus saving the memory
3. it produce binary program that does not contain any unresolved external references.
4. All of the above

• 1 only
• 1,2 only
• 1,3 only
• 4

B. 1,2 only Explanation :

19._____contains instructions and data of a program and information required for its relocation and linking.

• reentrant program
• object module
• Binary Program
• self-relocating program

B. object module

20.______ is ready to execute form of a program

• reentrant program
• object module
• Binary Program
• self-relocating program

C. Binary Program

21.In ________ linking is performed in a lazy manners,ie an object module defining a symbol is linked to a program only when that symbol is referenced during the program's execution.

• Dynamically linked program
• Object module
• Binary Program
• self-relocating program

A. Dynamically linked program

22._______ can relocate itself to execute in any area of memory

• Dynamically linked program
• Reentrant program
• Binary Program
• self-relocating program

D. self-relocating program

23.______ can be executed on several sets of data concurrently.

• Dynamically linked program
• Reentrant program
• Binary Program
• self-relocating program

B. Reentrant program

 

This MCQs section is mainly focused on below lists of topics

1. Use of stack..
2. The memory Allocation Model for a process.

 

1.Variables whose scope is associated with functions, procedures, or blocks, in a program and parameters of function or procedure calls. This kind of data is allocated on the___________

• Heap
• stack
• CPU register
• Program Counter

B. stack Explanation :

2.In Stack, Allocation and deallocations are performed in a _________Manner in response to push and pop operations.

• FIFO
• LIFO
• FILO
• LILO

B. LIFO Explanation :

3.A pointer called the ______ points to the first entry of the stack, while a pointer called the _____ points to the last entry allocated in the stack.

• top of Stack (TOS),Frame Base (FB)
• top of Stack (TOS),Stack Base (SB)
• Stack Base (SB),top of Stack (TOS)
• Frame Base (FB),top of Stack (TOS)

C. Stack Base (SB),top of Stack (TOS)

4.During execution of a program, a stack is used to support function calls. the group of stack entries that pertain to one function call is called

• stack
• Frame Base
• base Frame
• Stack frame

D. Stack frame Explanation :

5.Stack frame contains

• Address of the function's parameters
• values of the functions parameters
• the return address
• All of the above

D. All of the above Explanation :

6.The first entry in the stack frame contains

• The next value of the frame base.
• The previous value of the frame base.
• the return address of the function
• All of the above.

B. The previous value of the frame base.

7.The second entry in the stack frame contains

• The next value of the frame base
• The previous value of the frame base.
• the return address of the function
• All of the above.

C. the return address of the function

8.The frame base points to the

• Last entry in the stack frame
• the return address of the function
• the last local data in the stack frame
• First entry in the stack frame

D. First entry in the stack frame

9.The TOS points to the

• the last local data in the stack frame
• Last entry in the stack frame
• the return address of the function
• First entry in the stack frame

A. the last local data in the stack frame

10.The size of a program can be obtained from its

• Directory entry
• size of the stack
• PCD-program controlled dynamic data vary during execution of the program
• all of the above

D. all of the above

11.Which of the following statements stands TRUE for Memory Allocation Model?

1. The code and static data components in the program are allocated memory area that exactly matches their size.
2. The PCD data and stack share a single large area of memory but grow in opposite directions when memory is allocated to new data.
3. The PCD data is allocated by starting at the low end of this area while the stack is allocated by starting at the high end of the area. the memory between these two components is free.
4. In this model the stack and PCD data components do not have individual size restrictions.

• 1,4
• 1,2
• 1,3
• 1,2,3,4

D. 1,2,3,4 Explanation :

12.PCD data can be allocated deallocated by

• MMU
• run time libraries of the programming language ie.library routines
• Kernel
• All of the above

B. run time libraries of the programming language ie.library routines Explanation :

 
 This MCQs section is mainly focused on below lists of topics

1.Reuse of memory.
-Maintaining a free list.
-Performing fresh allocation by using a free lists.

• First-Fit Technique
• Best-Fit Technique
• Next-Fit Technique

 

1.A Heap permits allocation and deallocation of memory in a ________ Manner.

• Random and Sequential order
• Sequential order
• Random Order
• None of the above

C. Random Order Explanation :

2.__________allocators are used by run-time support of programming language to manage PCD data,and by the kernel to manage its own memory requirements.

• Stack
• heap
• stack and heap
• None of the above

B. heap Explanation :

3.The speed of memory and efficient used of memory are two fundamental concerns in the design of memory allocator._______allocation addresses both these concerns effectively.

• stack-based
• heap-based
• stack and heap based
• None of the above

A. stack-based Explanation :

4.In _____ allocator released memory is not reused automatically when fresh allocation are made.

• stack-based
• heap-based
• stack and heap based
• None of the above

B. heap-based Explanation :

5.Some memory are is left over when a fresh allocation is made in ___ allocator.

• stack-based
• heap-based
• stack and heap based
• None of the above

B. heap-based Explanation :

6.Which of the below kernel functions can be used for reuse of memory in heap management?

• Maintaining a free list.
• select a memory area for allocation.
• merge free memory area.
• All of the above

D. All of the above Explanation :

7.which of the following control information the kernel needs to maintains for each memory area in the free list;

• The size of the memory areas
• the pointers used for forming the lists.
• The size of the memory areas and the pointers used for forming the lists.
• Stack pointer

C. The size of the memory areas and the pointers used for forming the lists.

8.Which of the following free lists is used to facilitate faster insertion and deletion operations on memory area while managing the free lists.

• Singly linked free list.
• Doubly linked free list
• Stack
• singly linked free list and stack

B. Doubly linked free list Explanation :

9.Which of the following techniques can be used  to perform memory allocation by using a free list;

• First Fit technique
• Best-Fit technique
• Next-Fit technique
• All of the above.

D. All of the above.

10.To service a request for n bytes of memory,the _____ technique uses the first free memory area it can find whose size is ≥ n bytes.

• First Fit technique
• Best-Fit technique
• Next-Fit technique
• Good-Fit technique.

A. First Fit technique

11.The ____ technique uses the smallest free memory area with size ≥ n bytes.

• First Fit technique
• Best-Fit technique
• Next-Fit technique
• Good-Fit technique.

B. Best-Fit technique

12.The _____ technique remembers which entry in the free list was used to make the last allocation.to make new allocation,it searches the free list starting from the next entry and perform allocation using first free memory area whose size  ≥ n bytes that it can find.

• First Fit technique
• Best-Fit technique
• Next-Fit technique
• Good-Fit technique.

C. Next-Fit technique

13.________ technique may split memory area at the start of the free list repeatedly,so free memory area become smaller with time.

• First Fit
• Best-Fit
• Next-Fit
• worst-Fit

A. First Fit Explanation :

14.________ technique avoids needless splitting of large memory area.

• First Fit
• Best-Fit
• Next-Fit
• worst-Fit

B. Best-Fit

15.________ technique incurs higher allocation overhead

• First Fit
• Best-Fit
• Next-Fit
• worst-Fit

B. Best-Fit Explanation :

16.________ technique avoids splitting the same free area repeatedly also avoids allocation overhead.

• First Fit
• Best-Fit
• Next-Fit
• worst-Fit

C. Next-Fit

 

This MCQs section is mainly focused on below lists of topics
1.Memory Fragmentation

• Merging of free memory area
  1.Boundy tags
  2.Memory Compaction

2.Buddy System and Power of 2 Allocators.

• Buddy System Allocator
• Power of 2 Allocator

 

1.Memory fragmentation can be defined as

• The existence of usable area in the memory of computer system
• The existence of unusable area in the memory of computer system
• The existence of unreachable area in the memory of computer system
• None of the above

B. The existence of unusable area in the memory of computer system

2.External fragmentation occurs when a

• memory area remain unused because it is too large to be allocated
• memory area remain unused because it is too small to be allocated
• More memory is allocated than requested by the process
• less memory is allocated than requested by the process

B. memory area remain unused because it is too small to be allocated

3.Internal fragmentation occurs when a

• memory area remain unused because it is too large to be allocated
• memory area remain unused because it is too small to be allocated
• More memory is allocated than requested by the process
• less memory is allocated than requested by the process

C. More memory is allocated than requested by the process Explanation :

4.memory fragmentation results in_______

• stack overflow
• page faults
• Better Utilization of memory
• poor utilization of memory

D. poor utilization of memory

5.In External fragmentation,merging of free memory areas using boundary tags.which of the following statement stands TRUE.

1. Boundary tags ,is a status descriptor for a memory area.
2. It consists of an ordered pair giving allocation status of the area;whether it is free or allocated.
3. Boundary tags are identical tags stored at the start and end of memory area.
4. when an area of memory becomes free ,the kernel checks the boundary tags of its neighboring areas.

• 1,2 only
• 1,3 only
• 1,4 only
• 1,2,3,4

D. 1,2,3,4 Explanation :

6.A relation called the 50-percent rule holds

• When an area of memory is freed,the total number of free area in the system decreases by 1
• When an area of memory is freed,the total number of free area in the system increases by 1
• When an area of memory is freed,the total number of free area in the system remain the same depending on whether the area being freed has zero,two,or one free area as neighbors.
• All of the above

D. All of the above

7.Which of following statements stands true of a relation called 50-percent rule.

1. the number of free area is half the number of allocated area ie. m=n/2
2. it helps in estimating the size of the free list
3. it also gives us method of estimating the free area in the memory at any time
4. if sf is the average size of free area of memory,the total free memory is sf×n/2

• 1 only
• 1,2 only
• 1,2,3 only
• 1,2,3,4

D. 1,2,3,4 Explanation :

8.In________memory binding are changed in such manner that all free memory area can be merged to form a single free memory area.

• Memory Paging
• Memory Swapping
• Memory Compaction
• Memory segmentation

C. Memory Compaction Explanation :

9.Which of the following statements stands true for memory compaction method.

1. it involves movement of code and data in the memory.
2. it is feasible only if computer system provides relocation register;the relocation can be achieved by simply changing the address in the relocation register
3. it does not involves movement of code and data in the memory
4. it does not involves use of relocation register

• 1,2 only
• 3,4 only
• 2,3 only
• 1,4 only

A. 1,2 only Explanation :

10.Buddy system and power of 2 allocators leads to ___________

• External fragmentation
• Internal Fragmentation
• No fragmentation
• None of the above

B. Internal Fragmentation Explanation :

11.In the Binary buddy system the sizes of memory blocks are ___________ and separate free lists are maintained for blocks of ___________sizes.

• power of 2,same
• square of 2,same
• power of 2,different
• square of 2,different

C. power of 2,different

12.Which of the following statement is true for buddy system allocators?

1. Buddy System splits and recombines memory blocks in a predetermined manner during allocation and deallocation.
2. No splitting of blocks takes place, also no effort is made to coalesce adjoining blocks to form larger blocks; when released, a block is simply returned to its free list.
3.  When a request is made for m bytes, the allocator first check the free list containing blocks whose size is 2ⁱ for the smallest value of i such that 2ⁱ ≥ m.if the free list is empty ,it checks the list containing blocks that are higher the next higher power of 2 in size on so on. an entire block is allocated to a request.
4.  When a request is made for m bytes. the system finds the smallest power of 2 that is ≥ m. Let this be 2ⁱ.if the list is empty, it checks the lists for block of size 2ⁱ⁺¹.it takes one block off this list and splits it into two halves of size 2ⁱ.it put one of these blocks into the free list of size 2ⁱ,and uses the other block to satisfy the request.

• 1 only
• 1,2 only
• 2,3 only
• 1,4 only

D. 1,4 only Explanation :

13.Which of the following statement is true for Power-of-2 allocators?

1. Buddy System splits and recombines memory blocks in a predetermined manner during allocation and deallocation.
2. No splitting of blocks takes place, also no effort is made to coalesce adjoining blocks to form larger blocks; when released, a block is simply returned to its free list.
3.  When a request is made for m bytes, the allocator first check the free list containing blocks whose size is 2ⁱ for the smallest value of i such that 2ⁱ ≥ m.if the free list is empty ,it checks the list containing blocks that are higher the next higher power of 2 in size on so on. an entire block is allocated to a request.
4.  When a request is made for m bytes. the system finds the smallest power of 2 that is ≥ m. Let this be 2ⁱ.if the list is empty, it checks the lists for block of size 2ⁱ⁺¹.it takes one block off this list and splits it into two halves of size 2ⁱ.it put one of these blocks into the free list of size 2ⁱ,and uses the other block to satisfy the request.

• 1 only
• 1,2 only
• 2,3 only
• 1,4 only

C. 2,3 only Explanation :

14.The buddy and power of 2 allocators are faster than the first-fit ,best-fit, next-fit allocators

• TRUE
• FALSE

A. TRUE Explanation :

15.The power of 2 allocators is faster than the Buddy System allocators.

• TRUE
• FALSE

A. TRUE Explanation :

 

This MCQs section is mainly focused on below lists of topics

1. Contiguous Memory Allocation

2. NonContiguous Memory Allocation

• -Logical Addresses, Physical Addresses and Address translation
• -Approaches to Noncontiguous Memory allocation

1. Paging
2. Segmentation

 

1.Contiguous memory allocation is the classical memory allocation model in which

• Same process is allocated in a different area in the memory
• all the process is allocated a single contiguous area in the memory
• Each process is allocated a single contiguous area in the memory
• All of the above

C. Each process is allocated a single contiguous area in the memory

2.Contiguous memory allocation faces the problem of

• Memory fragmentation
• Page Faults
• less throughput
• Less hit ratio

A. Memory fragmentation

3.In Contiguous memory allocation _________ has no cure

• Internal fragmentation
• External fragmentation
• inline fragmentation
• outline fragmentation

A. Internal fragmentation Explanation :

4.The technique of memory compaction and reuse of memory can be applied to overcome the problem of

• Internal fragmentation
• External fragmentation
• Page Faults
• Swapping

B. External fragmentation

5.Memory compaction involves _________

• removing of memory
• No Relocation
• Static relocation
• Dynamic relocation

D. Dynamic relocation

6.Dynamic Relocation is not feasible without_____

• Program Counter
• Special Purpose Register
• Relocation Register
• Program status Word

C. Relocation Register

7.NonContiguous memory allocation is a model in which

• Portion of its address space are distributed among many areas of memory
• all the process is allocated a single continuous area in the memory
• Each process is allocated a single continuous area in the memory
• All of the above

A. Portion of its address space are distributed among many areas of memory

8.In NonContiguous memory allocation _______

• it increases the external fragmentation
• it reduce the external fragmentation
• it increases the internal fragmentation
• it reduce the internal fragmentation

B. it reduce the external fragmentation Explanation :

9.logical address is the address______

• constituents the physical address space
• of an instruction or data byte as used in a process.
• in a memory where an instruction or data byte exists
• All of the above

B. of an instruction or data byte as used in a process. Explanation :

10.physical address is the address______

• constituents the logical address space
• of an instruction or data byte as used in a process.
• in a memory where an instruction or data byte exists
• All of the above

C. in a memory where an instruction or data byte exists Explanation :

11.The CPU sends the __________ of each data or instruction used in the process to the MMU.

• Physical address
• logical address
• effective address
• None of the above

B. logical address

12.The MMU uses the memory allocation information stored in the table to compute the corresponding __________

• Physical address
• logical address
• effective address
• None of the above

A. Physical address

13.The procedure of computing the effective memory address from a logical address is called______

• physical address translation
• logical address translation
• address translation
• All of the above

C. address translation

14.in Non-contiguous memory allocation the kernel allocates a single memory area to a process.

• TRUE
• FALSE

B. FALSE Explanation :

15.In Contiguous allocation address translation is not required

• TRUE
• FALSE

A. TRUE Explanation :

16.In Contiguous allocation external fragmentation arises if first-fit,best-fit,or next-fit allocation is used.internal fragmentation arises if memory allocation is performed in blocks of a few standard sizes.

• TRUE
• FALSE

A. TRUE

17.In NonContiguous allocation unless the computer system provides the relocation register,swapped-in process must be places in its originally allocated area.

• TRUE
• FALSE

B. FALSE Explanation :

18.Which of the following is the fundamental approaches to implement Non-contiguous memory allocation?

1. Paging
2. Segmentation
3. Memory compaction
4. power of 2 allocator

• 1,2
• 2,3
• 3,4
• 1,4

A. 1,2

 
 1.In approaches to noncontiguous memory allocation, the memory can accommodate an integral number of pages. It is partitioned into memory areas that have same size as page. This approach is known as______

• Segmentation
• Paging
• Thrashing
• none of the above

B. Paging

2.Each process consists of fixed size component called _________

• Segment
• Page table
• Pages
• All of the above

C. Pages

3.In which of the memory allocation techniques internal fragmentation can arise

• Segmentation
• Paging
• Segmentation with paging
• All of the above

B. Paging Explanation :

4.Which of the following non contiguous memory allocation approach have component of different sizes, so that kernel has to use memory reuse techniques such as first-fit or best-fit allocation?

• Segmentation
• Paging
• Segmentation with paging
• All of the above

A. Segmentation

5.In ___________, a programmer identifies component in a process Called_________ in a process.

• Paging, Pages
• Segmentation, Pages
• Segmentation, Segments
• Segment table, Pages

C. Segmentation, Segments

6.Which of the following facilitates sharing of codes, data and program modules between processes?

• Segments
• Page table
• Pages
• Segment table

A. Segments

7.In which of the following memory allocation techniques external fragmentation can arise?

• Segmentation
• Paging
• Segmentation with paging
• All of the above.

A. Segmentation

8.In which of the following memory allocation techniques facilitates sharing of codes, data and program modules between processes without incurring external fragmentation?

• Segmentation
• Paging
• Segmentation with paging
• All of the above

C. Segmentation with paging

9.A process is considered to consists of pages numbered from ______ onward

• -1
• 1
• 2
• 0

D. 0

10.A process is considered to consist of pages. Each pages is of size s bytes, where s is power of ____

• -1
• 1
• 2
• 0

C. 2

 1.A memory hierarchy ,consisting of a computer system’s memory and a disk, that enables a process to operate with only some portion of its address space in memory known as _______

• RAM
• ROM
• Virtual memory
• Disk

C. Virtual memory

2.A software component of Virtual memory is known as __________

• Memory management unit
• Virtual memory manager
• Memory manager
• All of the above.

B. Virtual memory manager

3.Which of the following translate the logical address of the code in the instructions of a process into the address in memory where the operand or instruction actually resides?

• Memory management Unit
• Virtual memory manager
• Software Management Unit
• A and B both

D. A and B both

4.A memory  that is larger than the real memory of the computer system is ______

• RAM
• ROM
• Disk
• Virtual Memory

D. Virtual Memory

5.The ___________loads only one component of a process address space in memory to begin with-the component that contain starting address of the process.

• Memory management Unit
• Virtual memory manager
• Memory manager
• All of the above.

B. Virtual memory manager

6.The virtual memory manager loads other components of the process only when they are needed. This techniques is called____________

• Thrashing
• Swapping
• Demand paging
• Segmentation

C. Demand paging Explanation :

7.The performance of a process in virtual memory depends on the rate at which its components have to be loaded into memory. to achieve a low rate of loading of process components Virtual memory manager uses the ________

• Law of locality of objects
• Law of locality of pointers
• Thrashing
• Law of locality of reference

D. Law of locality of reference

8.Classify the below statement as true or false. as far as functions of the virtual memory manager is concerned it manage logical address space

• True
• False

A. True Explanation :

9.Classify the below statement as true or false. as far as functions of the virtual memory manager is concerned it manages memory.

• True
• False

A. True Explanation :

10.Classify the below statement as true or false. as far as functions of the virtual memory manager is concerned it implement memory protection.

• True
• False

A. True Explanation :

11.Classify the below statement as true or false. as far as functions of the virtual memory manager is concerned it collects page reference information

• True
• False

A. True Explanation :

12.Classify the below statement as true or false. as far as functions of the virtual memory manager is concerned it Does not perform page replacement.

• True
• False

B. False Explanation :

13.Allocate physical memory is not a function of virtual memory manager

• True
• False

B. False Explanation :

14.Virtual memory manager implement page sharing functionality

• True
• False

A. True Explanation :

 1.The memory of the computer system is considered to consist of page frames, where a page frame is memory area that has the same size as a ____

• Page Table
• Page
• Segment
• Page frame table

B. Page

2.Page frames are numbered from ______ Where #frames is the number of page frame of memory

• 1 to #frames
• 1 to #frames-1
• 0 to #frames -1
• Any of the above

C. 0 to #frames -1

3.Each logical address used in a process is considered to be a pair (p_i,b_i), where p_i  is a page number and b_i  is the byte number in p_i, Each page is of size s And 0 ≤ b_i  < s . The effective memory address of a logical address (p_i,b_i) is computed as follows:

• effective memory address of a logical address (p_i,b_i) = Start address of the Segment containing page p_i  + b_i
• effective memory address of a logical address (p_i,b_i) = Start address of the Page Frame containing page p_i  + b_i
• effective memory address of a logical address (p_i,b_i) = Start address of the Page Frame containing page p_i  - b_i
• None of the above.

B. effective memory address of a logical address (p_i,b_i) = Start address of the Page Frame containing page p_i  + b_i

4.Memory allocation information for a process is stored in a _______

• Page table
• Frame table
• Pages
• Frame list

A. Page table Explanation :

5.The page table for a process facilitates implementation of address translation, demand loading, and page replacement operations. Which of the followings are the fields in a page table entry

• Valid bit
• Page frame#
• Modified
• Prot info
• All of the above.

E. All of the above.

6.Which of the following field in a page table entry indicates whether the page described by the entry currently exists in memory?

• Valid bit
• Page frame#
• Modified
• Prot info

A. Valid bit

7.Which of the following field in a page table entry indicates which page frame of memory is occupied by the page?

• Valid bit
• Page frame#
• Modified
• Prot info

B. Page frame#

8.Which of the following field in a page table entry indicates how the process may use contents of the page - whether read, write, or execute?

• Ref info
• Modified
• Prot info
• Other info

C. Prot info

9.Which of the following field in a page table entry indicates information concerning references made to the page white it is in memory?

• Ref info
• Modified
• Other info
• Prot info

A. Ref info

10.Which of the following field in a page table entry indicates whether the page has been modified while in memory?

• Ref info
• Modified
• Other info
• Prot info

B. Modified

11.Which of the following field in a page table entry indicates other useful information concerning the page e.g., its position in the swap space?

• Ref info
• Modified
• Other info
• Prot info

C. Other info

12.Which of the following field in the page table entry is also known as presence bit?

• Valid bit
• Page frame#
• Modified
• Prot info

A. Valid bit

13.Which of the following field in the page table entry is also known as dirty bit, and this field is single bit?

• Valid bit
• Page frame#
• Modified
• Prot info

C. Modified

14.Which of the following field is used to decide whether a page out operation is needed while replacing the page?

• Valid bit
• Page frame#
• Modified
• Prot info

C. Modified Explanation :

15.Which of the following is the step performed in address translation by the MMU?

• Look up page table
• Obtain page number and byte number in a page
• Form effective memory address.
• All of the above.

D. All of the above.

16.When a page is not present in the memory ,MMU raises an interrupt called a __________

• Page hit
• Page miss
• Page Fault
• All of the above.

C. Page Fault Explanation :

17.Which of the following operations are performed by the Virtual memory manager when page fault occurs?

• Page in
• Page out
• Page replacement operations
• All of the above.

D. All of the above.

18.The virtual memory manager uses a page replacement algorithm to select one of the pages currently in memory for replacement, accesses the page table entry of the selected page to mark it as “not present” in memory and initiates a ________operation for it if the modified bit of its page table entry indicates that it is dirty page.

• Page hit
• Page out
• Page Miss
• Page in

B. Page out

19.The virtual memory manager initiates a _____ operation to load the required page into the page frame that was occupied by the selected page and it updates the page table entry of the page to record frame number of the page frame, marks the page as “present” and makes provision to resume operation of the process.

• Page hit
• Page out
• Page Miss
• Page in

D. Page in

20.Page-in and page-out operations are required to implement demand paging constitutes _______

• Page I/O
• Process I/O
• Program I/O
• Disk I/O.

A. Page I/O

21.Which of the following stands true for Effective memory access time for a process in demand paging?

• Only Time consumed by the MMU in performing address translation
• Only the average time consumed by the virtual memory manager in handling a page fault
• Time consumed by the MMU in performing address translation and the average time consumed by the virtual memory manager in handling a page fault
• None of the above.

C. Time consumed by the MMU in performing address translation and the average time consumed by the virtual memory manager in handling a page fault Explanation :

22.Which of the following stands true for Effective memory access time for a process in demand paging? Where pr₁  = probability that a page exists in memory, t_mem = memory access time , t_pfh = time overhead of page fault handling

• Effective memory access time = pr₁ × 2 × t_mem + (1 - pr₁ ) × (t_mem + t_pfh + 2 × t_mem)
• Effective memory access time = pr₁ × 1 × t_mem+ (1 - pr₁ ) × (t_mem + t_pfh + 2 × t_mem
• Effective memory access time = pr₁ × 1 × t_mem1 ) × (t_mem + t_pfh + 2 × t_mem)
• Effective memory access time = pr₁ × 2 × t_mem - (1 + pr₁ ) × (t_mem + t_pfh + 2 × t_mem )

A. Effective memory access time = pr₁ × 2 × t_mem + (1 - pr₁ ) × (t_mem + t_pfh + 2 × t_mem) Explanation :

1.Page replacement becomes necessary when

1. Page faults occur and there are no free page frames in the memory.
2. Page faults occur and there are free page frames in the memory.
3. Page faults would arise if the replaced page is referenced again.
4. It is important to replace a page that is not likely to be referenced again in the immediate future.

• 1 only
• 1 and 3 only
• 1 , 2 and 4 only
• 1,3 and 4 only

D. 1,3 and 4 only

2.Which of the following statements stands true for locality of reference in page replacement and handling page faults?

• It states that the physical addresses used by a process in any short interval of time during its operation tend to be bunched together in certain portion of its logical address space.
• It states that the logical addresses used by a process in any short interval of time during its operation tend to be bunched together in certain portion of its logical address space.
• It states that the physical addresses used by a process in any short interval of time during its operation tend to be bunched together in certain portion of its physical address space.
• It states that the logical addresses used by a process in any Long interval of time during its operation tend to be bunched differently in certain portion of its logical address space.

B. It states that the logical addresses used by a process in any short interval of time during its operation tend to be bunched together in certain portion of its logical address space. Explanation :

3.The computer exploits the law of locality to ensure__________

• More page faults and high hit ratio in cache
• Fewer page faults and high hit ratio in the disk
• High hit ratio in the cache and fewer page faults
• None of the above.

C. High hit ratio in the cache and fewer page faults

4.How much memory should the virtual memory manager allocates to a process depends on which of the below factors?

• An overcommitment of memory to a process implies a low page fault rate for the process;hence it ensures good process performance.
• An undercommitment of memory to a process causes a high page fault rate,which would lead to poor performance of the process
• In An overcommitment of memory to a process however if a smaller number of processes would fit in memory which would causes CPU idling and poor system performance.
• All of the above.

D. All of the above.

5.When a process is operating in low memory allocation and has high page fault rate, this process spends a lot its time in the ____________

• Active state
• Pending State
• Blocked State
• Ready State

C. Blocked State

6.A situation where All the processes in the system operate in the region of high page fault rates, the CPU would be engaged in performing page traffic and process switching most of the time and throughput would be poor Called________

• Swapping
• Switching
• Paging
• Thrashing

D. Thrashing

7.A situation where too few processes exists in memory or all process in memory perform I/O operations frequently is called _______

• Swapping
• Context Switching
• Paging
• Thrashing

D. Thrashing Explanation :

8.Which of the following Statement stands true for the optimal page size of process? It determines______

1. the number of bits required to represent the byte number in a page
2. Memory wastage due to internal fragmentation
3. Size of page table for a process
4. Page Fault rates when a fixed amount of memory is allocated to a process

• 1 Only
• 1 and 2 only
• 1,2 and 3 only
• All of the above.

D. All of the above.

9.Consider a process P_i of size z A page size of s bytes implies that the process has an n pages, where ______

• n = [z/s]
• n = [s/z]
• n = [zs]
• n = [z - s]

A. n = [z/s]

10.Consider a process P_i of size z bytes. A page size of s bytes implies that the process has an n pages, where n = [z/s] .An Average internal fragmentation is __________

• s bytes
• s/2 bytes
• 1/s bytes
• 2s bytes

B. s/2 bytes

11.The MMU contains special register called__________ to point to the start of a page table

• Page address resistor (PAR)
• Page Frame Address resistor (PFAR)
• Page table Address resistor (PTAR)
• Page table size Resistor (PTSR)

C. Page table Address resistor (PTAR) Explanation :

12.Kernel can store the address of the page table of a process in its _________

• Relocation Register
• Process Control block
• Stack
• Heap

B. Process Control block

13.The MMU provides a special register called the ______ if a process tries to access a nonexistent page, or exceeds its access privileges while accessing a page. and a memory protection interrupt raised.

• relocation register
• page table address register
• page table size register
• Process control block

C. page table size register

14.Which of the following is the function of paging hardware

• Memory protection
• Efficient address translation
• Page replacement support
• All of the above.

D. All of the above.

15.The ________ is a small and fast associative memory that is used to eliminate the reference to the page table.

• PCB
• VM Manager
• Free frame list
• TLB

D. TLB Explanation :

16.The TLB contains entries of the form ________ for a few recently accessed pages of a program that are in memory.

• Valid bit, page frame #, Prot info
• Page # , Page frame # , Prot info
• Valid bit, page frame #, Page #
• Page # , Page frame # , Valid bit

B. Page # , Page frame # , Prot info Explanation :

17.A probability that a page exists in memory is known as _______

• TLB hit ratio
• TLB miss ratio
• Memory hit ratio
• Memory miss ratio

C. Memory hit ratio

18.A probability that a page exists in TLB is known as _______

• TLB hit ratio
• TLB miss ratio
• Memory hit ratio
• Memory miss ratio

A. TLB hit ratio

19.When TLB is used for a address translation, effective memory access time is ______ Where Pr₁ = Probability that page exists in memory Pr₂ = Probability that page exists in TLB t_mem = memory access time t_TLB = access time of TLB t_pfh = time overhead of page fault handling

• Pr2 × (tTLB + tmem ) + (Pr1 - Pr2) × (tTLB + 2 × tmem) - (1 - Pr1) × (tTLB + tmem + tpfh + tTLB + 2 × tmem)
• Pr2 × (tTLB + tmem ) - (Pr1 - Pr2) × (tTLB + 2 × tmem) - (1 - Pr1) × (tTLB + tmem + tpfh + tTLB + 2 × tmem)
• Pr2 × (tTLB + tmem ) + (Pr1 - Pr2) × (tTLB + 2 × tmem) + (1 - Pr1) × (tTLB + tmem + tpfh + tTLB + 2 × tmem)
• Pr2 × (tTLB - tmem ) + (Pr1 + Pr2) × (tTLB - 2 × tmem) + (1 - Pr1) × (tTLB - tmem + tpfh + tTLB + 2 × tmem)

C. Pr2 × (tTLB + tmem ) + (Pr1 - Pr2) × (tTLB + 2 × tmem) + (1 - Pr1) × (tTLB + tmem + tpfh + tTLB + 2 × tmem)

20.Which of the following is used to reduce the size of memory committed to page tables?

• Inverted page table
• Single level page table
• Multilevel page table
• Both a and c.

D. Both a and c.

21.In which of the following the page table of a process is itself is paged; the entire page table therefore does not need to exist in memory at any time?

• Inverted page table
• Single level page table
• Multilevel page table
• Multiprogramming page table

C. Multilevel page table Explanation :

22.In which of the following the size of page table is governed by the size of memory, so it is independent of the number and size of processes. However information about a page cannot be accessed directly as in page table?

• Inverted page table
• Single level page table
• Multilevel page table
• Multiprogramming page table

A. Inverted page table Explanation :

 

1.Page replacement policy should replace a page that is _____

• Likely to be referenced in the immediate future
• Not Likely to be referenced in the immediate future
• Currently in use by the process
• None of the above.

B. Not Likely to be referenced in the immediate future

2.In which of the following Page replacement Algorithm making pages replacement decisions in such a manner that the total number of page faults during operation of a process is the minimum possible?

• LRU Page replacement Algorithm
• FIFO page replacement Algorithm
• Optimal page replacement algorithm
• NRU Page replacement algorithm

C. Optimal page replacement algorithm

3.In which of the following Page replacement Policy, at every page fault the page replacement policy replaces the page that was loaded into memory earlier than any other page of the process?

• LRU Page replacement Algorithm
• FIFO page replacement Algorithm
• Optimal page replacement algorithm
• NRU Page replacement algorithm

B. FIFO page replacement Algorithm

4.To facilitate FIFO Page replacement, the virtual memory manager records the time of loading of a page in the _________ field of its page table entry.

• Prot info
• Valid bit
• Ref info
• None of the above.

C. Ref info

5.To facilitate Optimal Page replacement, the virtual memory manager records the time of loading of a page in the _________ field of its page table entry.

• Prot info
• Valid bit
• Ref info
• None of the above.

C. Ref info

6.To facilitate LRU Page replacement, the virtual memory manager records the time of loading of a page in the _________ field of its page table entry.

• Prot info
• Valid bit
• Ref info
• None of the above.

C. Ref info

7.In which of the following Page replacement Policy uses the law of locality of reference as the basis for its replacement decisions?

• LRU Page replacement Algorithm
• FIFO page replacement Algorithm
• Optimal page replacement algorithm
• NRU Page replacement algorithm

A. LRU Page replacement Algorithm Explanation :

8.To achieve the desirable page fault characteristic , a page replacement policy must possess the _________

• Heap property
• Array Property
• Stack Property
• All of the above.

C. Stack Property

9.Which of the following page replacement algorithm exhibit the stack property ?

• LRU Page replacement Algorithm
• FIFO page replacement Algorithm
• Optimal page replacement algorithm
• NRU Page replacement algorithm

A. LRU Page replacement Algorithm

10.Belady’s Anomaly occurs in which of the following page replacement algorithm?

• LRU Page replacement Algorithm
• FIFO page replacement Algorithm
• Optimal page replacement algorithm
• NRU Page replacement algorithm

B. FIFO page replacement Algorithm

11.Which of the following statement stands true for Belady’s anomaly?

• The number of page fault decreases when memory allocation for the process is increased
• The number of page fault increases when memory allocation for the process is decreased
• The number of page fault increases when memory allocation for the process is increased
• None of the above.

C. The number of page fault increases when memory allocation for the process is increased

12.In which of the following algorithm it is possible to combat thrashing by increasing the value of alloc for each process?

• LRU Page replacement Algorithm
• FIFO page replacement Algorithm
• Optimal page replacement algorithm
• NRU Page replacement algorithm

A. LRU Page replacement Algorithm Explanation :

13.In which of the following Algorithm where the reference bit is used to determine whether a page has been recently referenced, and some page that has not been recently referenced is replaced?

• LRU Page replacement Algorithm
• FIFO page replacement Algorithm
• Optimal page replacement algorithm
• NRU Page replacement algorithm

D. NRU Page replacement algorithm Explanation :