Unit 4 Memory Management of Operating System
Long Answer Question with Answer
Q1 Explain Memory management and Its Requirements?
Q2 What do you mean by address Binding?
Q3 Write a Short note on Overlays and Swapping?
Q4 Consider a Logical Address Space of Eight Page of 1024 words, each mapped onto a physical memory of 32 frame then
a. How many bits are in Logical Address?
b. How many bits are in Physical Address?
Q5 Discuss fixed and Dynamic Partitioning in detail? Also mention there drawback?
Q6 Explain the difference between internal and external fragmentation?
Q7 What are the difference techniques to remove fragmentation in case of multiprogramming with fixed partitions and variable partitions?
Q8 Given memory partitions of 100K, 500K, 200K, 300K and 600K. How would each of the first fit, best fit, and worst fit algorithms place processes of 212K, 417K, 112K and 426K? Which algorithm makes the most efficient use of memory?
Q9 What do you mean by paging? How page table can be implemented?
Q10 What is paging? Describe how logical address is translated to physical address in a paged system? Further give reasons as to why page sizes are always kept, in power of 2?
Q11 Under what circumstances do page faults occur? Describe the actions taken by the operating system when a page fault occurs?
or
When do page faults occur? Describe in details the action taken by the operating system when page fault occurs?
Q14 Explain the address translation scheme in the segmented paging with the help of diagram?
or
Discuss the paged segmentation scheme of memory management and explain how logical address?
Q15 How segmentation different from paging? discuss the address translation scheme in segmented paging with the help of a diagram?
or
Write the difference between paging and segmentation?
Q16 on a system using paging and segmentation the virtual address space consist of up to 16 segments where each segment can be up to 26 bytes long? The hardware pages each segments into 512 bytes pages? How many bits in virtual address specify the following?
1. Segment number
2. Page number
3. Offset within page
4. Entire virtual address
Q17 Explain the process of demand paging?
Q18 consider a demand paging system? Page table are held in registers. It takes 8 milliseconds to service the page fault if an empty page is available or the replaced page modified and 20 millisecond if the replaced page is modified? Memory access time is 100 nanoseconds? Assumed that the page to be replaced is modified 70 percent of the time? What is the maximum acceptable page fault rate for an effective access time of not more than 200 nanosecond?
Q19 Consider a demand paged system? Page tables are stored in the main memory which has an access time of 100 nanosecond. The TLB can hold 8 page table entries and has an access time of 10 nanosecond. During execution of process it is found that 80% of the time, a require page table entry exits in TLB and only 2% of the references cause page faults? The average time to service page fault is 2 millisecond? Compute the effective memory access time?
Q20 Consider the following reference string 1,2,3,4,1,2,1,5,6,2,1,2,3,7,6,3,2,1,2,3,6. How many page faults will occur for
1. FIFO
2. LRU page replacement technique
Assume three and four frames in each case and frame are initially empty?
Q21 How many page faults would occur for the following reference string for four page frame using LRU and FIFO algorithm?
1,2,3,4,5,5,3,4,1,6,7,8,7,8,9,7,8,9,5,4,5,4,2
Q22 consider the following reference string 1,2,3,4,2,1,5,6,2,1,2,3,7,6,3,2,1,2,3,6 how many page faults will occur for FIFO and LRU assuming three nd four frame in each case?
Q23 Discuss the LRU page replacement policy? Prove that this policy do not suffer from Belady’s anomaly? How many page faults would occur with LRU policy for the following reference string: 1,2,3,3,4,1,5,3,4,1,6,7,8,7,8,9,8,7,8,9,5,4,5,4,2 assume there are four frames which are initially empty?
Q24 What is Thrashing? State the cause of thrashing and discuss its solution?
Q25 What is the cause of Thrashing? How does system detect thrashing? Once it detects thrashing what can system do to eliminate this problem?
