Memory management questions and answers for Gate

Memory management questions and answers

This post covers the memory management questions and answers for GATE exam. Various gate questions on virtual memory are explained in this post.So let’s practice these operating system memory management questions and answers for gate exam.
Q1. Increasing the RAM of a laptop usually improves performance because:
A.Virtual memory will increase
B.Larger RAMs area unit quicker
C.Fewer page faults occur
D.Fewer segmentation faults occur.
Q2. Page fault happens 
A.When a requested page is in memory
B.When a requested page isn’t in memory
C.When a page is currupted
D.When associate degree exception is thrown
Q3. Which of the subsequent page replacement algorithms suffers from Belady’s anomaly?
C.Optimal Page Replacement
D. None
Q4.What is the disc space within the disk used for?
(A) Saving temporary HTML pages
(B) Saving method knowledge
(C) Storing the super-block
(D) Storing device drivers
Q5. A processor uses thirty six bit physical addresses and thirty two bit virtual addresses, with a page frame size of four Kbytes. Every page table entry is of size four bytes. a 3 level page table is employed for virtual to physical address translation, wherever the virtual address is employed as follows
• Bits 30-31 area unit accustomed index into the primary level page table
 • Bits 21-29 area unit accustomed index into the second level page table
• Bits 12-20 area unit accustomed index into the third level page table, and
• Bits 0-11 area unit used as offset within the page the quantity of bits needed for addressing consequent level page table (or page frame) within the page table entry of the primary, second and third level page tables area unit severally.
A.20, 20 and 20
B.24, 24 and 24
C.24, 24 and 20
Q6. A multilevel page table is most popular compared to one level page table for translating virtual address to physical address as a result of
A.It reduces the operation time to browse or write a memory location.
B.It helps to cut back the dimensions of page table required to implement the virtual address area of a method.
C.It is needed by the interpretation look aside buffer.
D.It helps to cut back the quantity of page faults in page replacement algorithms.
Q7. Thrashing happens
A.When a page fault happens
B.Processes on system area unit in running state
D.Processes on system area unit in waiting state
Q8.A computer system supports 32-bit virtual addresses similarly as 32-bit physical addresses. Since the virtual address area is of constant size because the physical address area, the operating system designers attempt to get get rid of the virtual memory entirely.Which  one in all the subsequent is true?
A.Efficient implementation of multi-user support isn’t any longer potential
B.The processor cache organization is created additional economical currently
C.Hardware support for memory management isn’t any longer required
D.CPU planning is created additional economical currently
gate questions on virtual memory
Q9. A laptop uses 46–bit virtual address, 32–bit physical address, and a three–level paged page table organization. The page table base register stores the base address of the first–level table (T1), that occupies specifically one page. every entry of T1 stores the base address of a page of the second–level table (T2). every entry of T2 stores the base address of a page of the third–level table (T3). every entry of T3 stores a page table entry (PTE). The PTE is thirty two bits in size. The processor employed in the pc encompasses a one MB sixteen way set associative virtually indexed physically labeled cache. The cache block size is sixty four bytes. What is the size of a page in KB during this computer? (GATE 2013)
Q10. Assume information given within the question 9. what’s the minimum variety of page colors required to ensure that no 2 synonyms map to completely different sets within the processor cache of this computer? (GATE  2013)
Q11. The essential content(s) in every entry of a page table is / area unit
A.Virtual number
B.Page frame number
C.Both virtual page number and page frame number
D.Access right info
Q12.A system uses first in first out policy for page replacement. it’s four page frames with no pages loaded to start with. The system initial accesses a hundred distinct pages in some order so accesses  hundred distinct pages in some order and then wants to access 100 pages in  reverse order. what number page faults can occur?
Q13.Let the page fault service time be 10ms in an exceedingly laptop with average access time of  20ns. If one page fault is generated for each 10^6 memory accesses, what’s the effective access time for the memory?
Q14. Assume the virtual page reference string 1, 2, 3, 2, 4, 1, 3, 2, 4, 1 On a requirement paged memory board system running on computer system that main memory size of three pages frames that are empty initially . Let LRU, first in first out and optimal algorithm denote the quantity of page faults under the corresponding page replacements policy. Then
A.OPTIMAL < LRU < first in first out
B.OPTIMAL < first in first out < LRU
D.OPTIMAL = first in first out
Q15. Which of the subsequent needs a tool driver? (GATE  2001)
a) Register
b) Cache
c) Main memory
d) Disk
Answer Sheet

(1) C (2) B (3) A (4) B (5)    D   (6)    B      (7)    B      (8)    C     (9)    C     (10)     C     (11)  B       (12)   A      (13)     B (14)         B        (15)          D

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