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Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 1 (Page No. 332)
Give five different path names for the file /etc/passwd. (Hint: Think about the directory entries ‘‘.’’ and ‘‘..’’.)
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 55 (Page No. 261 - 262)
Write a program that can be used to compare the effectiveness of adding a tag field to $TLB$ entries when control is toggled between two programs. The tag ... nontrivial) input example.Plot the number of $TLB$ updates per $1000$ references.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 54 (Page No. 261)
Write a program that will demonstrate the difference between using a local page replacement policy and a global one for the simple case of two processes. You ... the per-process page fault rate with that of the local policy approach.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 53 (Page No. 261)
Write a program that demonstrates the effect of $TLB$ misses on the effective memory access time by measuring the per-access time it takes to stride ... computer with a different architecture and explain any major differences in the output.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 52 (Page No. 260 - 261)
Write a program that simulates a toy paging system that uses the $\text{WSClock}$ algorithm. The system is a toy in that we will assume there are ... needed to extend the program to handle a page reference stream that also includes writes.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 51 (Page No. 260)
Write a program that simulates a paging system using the aging algorithm. The number of page frames is a parameter. The sequence of page references should be ... $1000$ memory references as a function of the number of page frames available.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 50 (Page No. 260)
Plot a histogram and calculate the mean and median of the sizes of executable binary files on a computer to which you have access. On a Windows system, look ... all programs are equally likely to be run and thus should be weighted equally.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 49 (Page No. 260)
Virtual memory provides a mechanism for isolating one process from another. What memory management difficulties would be involved in allowing two operating systems to run concurrently? How might these difficulties be addressed?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 48 (Page No. 260)
Can you think of any situations where supporting virtual memory would be a bad idea, and what would be gained by not having to support virtual memory? Explain.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 47 (Page No. 259 - 260)
We consider a program which has the two segments shown below consisting of instructions in segment $0,$ and read/write data in segment $1.$ Segment $0$ has read/execute ... offset $28$Jump to location in segment $1,$ page $3,$ offset $32$
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 46 (Page No. 259)
When segmentation and paging are both being used, as in $MULTICS,$ first the segment descriptor must be looked up, then the page descriptor. Does the $TLB$ also work this way, with two levels of lookup?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 45 (Page No. 259)
Explain the difference between internal fragmentation and external fragmentation. Which one occurs in paging systems? Which one occurs in systems using pure segmentation?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 44 (Page No. 259)
A machine-language instruction to load a $32-bit$ word into a register contains the $32-bit$ address of the word to be loaded. What is the maximum number of page faults this instruction can cause?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 43 (Page No. 259)
A group of operating system designers for the Frugal Computer Company are thinking about ways to reduce the amount of backing store needed in their new operating system. ... text? Under what conditions, if any, does it work for the data?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 42 (Page No. 259)
It has been observed that the number of instructions executed between page faults is directly proportional to the number of page frames allocated to a program. If the ... how long would it take to run if twice as much memory were available?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 41 (Page No. 259)
A computer provides each process with $65,536$ bytes of address space divided into pages of $4096$ bytes each. A particular program has a text size of $32,768$ ... contain either text, data, or stack, not a mixture of two or three of them.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 40 (Page No. 259)
One of the first timesharing machines, the $DEC\: PDP-1,$ had a (core) memory of $4K\: 18-bit$ words. It held one process at a time in its memory. When ... any word, rather than only at word $0.$ Why do you suppose this drum was chosen?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 39 (Page No. 259)
You have been hired by a cloud computing company that deploys thousands of servers at each of its data centers. They have recently heard that it would be ... that be done?Under what conditions would the approach be worthwhile? Be feasible?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 38 (Page No. 258)
Consider the following two-dimensional array:int X[64][64];Suppose that a system has four page frames and each frame is $128$ words (an integer occupies one word). Programs that manipulate the ... for (int j = 0; j < 64; j++) X[i][j] = 0;
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 37 (Page No. 258)
Suppose that two processes $A$ and $B$ share a page that is not in memory. If process $A$ faults on the shared page, the page table entry for ... page into memory? Explain. What is the potential cost of delaying the page table update?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 36 (Page No. 258)
A computer has four page frames. The time of loading, time of last access, and the $R$ and $M$ bits for each page are as shown below (the ... Which page will FIFO replace?Which page will LRU replace?Which page will second chance replace?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 35 (Page No. 258)
How long does it take to load a $64-KB$ program from a disk whose average seek time is $5\: msec,$ whose rotation time is $5 msec,$ and whose ... cylinders is so large that the chance of two pages being on the same cylinder is negligible.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 34 (Page No. 257)
A student has claimed that in the abstract, the basic page replacement algorithms (FIFO, LRU, optimal) are identical except for the ... algorithm? Optimal algorithm?Give the generic algorithm for these page replacement algorithms.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 33 (Page No. 257)
Suppose that the $\text{WSClock}$ page replacement algorithm uses a $\tau$ ... of the new table entries. Explain. (You can omit entries that are unchanged.)
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 32 (Page No. 257)
In the $\text{WSClock}$ algorithm of Fig. $3-20(c),$ the hand points to a page with $R = 0.$ If $\tau = 400,$ will this page be removed? What about if $\tau = 1000?$
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 31 (Page No. 257)
Give a simple example of a page reference sequence where the first page selected for replacement will be different for the clock and $LRU$ page replacement algorithms. ... reference string contains page numbers from the set $0, 1, 2, 3.$
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 30 (Page No. 257)
A small computer on a smart card has four page frames. At the first clock tick, the $R$ bits are $0111\:\: ($page $0$ is $0,$ the rest are $1).$ ... is used with an $8-bit$ counter, give the values of the four counters after the last tick.
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 29 (Page No. 257)
Consider the page sequence of Fig. $3-15(b)$. Suppose that the $R$ bits for the pages $B$ through $A$ are $11011011,$ respectively. Which page will second chance remove?
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 28 (Page No. 257)
If $FIFO$ page replacement is used with four page frames and eight pages, how many page faults will occur with the reference string $0172327103$ if the four frames are initially empty? Now repeat this problem for$ LRU.$
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 27 (Page No. 256 - 257)
Suppose that the virtual page reference stream contains repetitions of long sequences of page references followed occasionally by a random page reference. For example, the ... better than the $\text{LRU, FIFO, or clock} $ algorithms.
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