8.13. In discussing a page replacement algorithm, one author makes an analogy with a snowplow moving around a circular track. Snow is falling uniformly on the track and a lone snowplow continually circles the track at constant speed. The snow that is plowed W the track disappears from the system. a. For which of the page replacement algorithms discussed in Section 8.2 is this a useful analogy? b. What does this analogy suggest about the behavior of the page replacement algo- rithm in question?

8.13. In discussing a page replacement algorithm, one author makes an analogy with a snowplow moving around a circular track. Snow is falling uniformly on the track and a lone snowplow continually circles the track at constant speed. The snow that is plowed W the track disappears from the system. a. For which of the page replacement algorithms discussed in Section 8.2 is this a useful analogy? b. What does this analogy suggest about the behavior of the page replacement algo- rithm in question?

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

See similar textbooks

Similar questions

One of my students asserted that, in the abstract, the three basic page replacement algorithms (FIFO, LRU, and optimum) are similar except for the characteristic that is utilised for picking the page to be replaced. I disagreed.(a) What is the attribute of the FIFO algorithm that you are referring to? What is the LRU algorithm? What exactly is the pptimal algorithm?The generic algorithm for these page replacement algorithms should be provided in (b).
Consider a system with four page frames and a program that uses eight pages. Consider the reference string 0 1 7 2 0 3 1 7 0 1 7 and assume that all four page frames are initially empty. Consider the three following algorithms: a. Optimal page replacement b. FIFO page replacement c. LRU page replacement In each cases show a diagram (ASCII art recommended) that shows which pages are in which frames throughout time, and page faults at the bottom. For instance: would mean that at step 1 page 0 is referenced and loaded into frame 0, which is a page fault; then page 1 is referenced, and so on. The goal is to fill this table to see what in memory when and thus infer the number of page faults. The first 4 steps are ALWAYS the same, as above (i.e., just fill the four frames, with one page fault each time)
Consider a system with four page frames and a program that uses eight pages. Consider the reference string 0 1 7 2 0 3 1 7 0 1 7 and assume that all four page frames are initially empty. Consider the three following algorithms: a. Optimal page replacement In each cases show a diagram (ASCII art recommended) that shows which pages are in which frames throughout time, and page faults at the bottom. For instance: The first 4 steps is ALWAYS the same (i.e., just fill the four frames, with one page fault each time)
In discussing a page replacement algorithms, one author makes an analogy with a snowplow moving around a circular track. Snow is falling uniformly on the track, and a lone snowplow continually circles the track at constant speed. The now that is lowed off the track disappears from the system. For which of the page algorithms is this a useful analogy and why?
5.04-2. Bellman Ford Algorithm (1, part 2). Consider the scenario shown below, where at t=1, node e receives distance vectors from neighboring nodes d, b, h and f. The (old) distance vector at e (the node at the center of the network) is also shown, before receiving the new distance vector from its neighbors. Indicate which of the components of new distance vector at e below have a value of 2 after e has received the distance vectors from its neighbors and updated its own distance vector.
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 sequence: 0, 1, ... , 511, 431, 0, 1, ... , 511, 332, 0, 1, ... consists of repetitions of the sequence 0, 1, ... , 511 followed by a random reference to pages 431 and 332. (a) Why will the standard replacement algorithms (LRU, FIFO, clock) not be effective in handling this workload for a page allocation that is less than the sequence length? (b) If this program were allocated 500 page frames, describe a page replacement approach that would perform much better than the LRU, FIFO, or clock algorithms.
Consider a scheduling problem, where there are five activities to be scheduled in four time slots. Suppose we represent the activities by the variables A, B, C, D, and E, where the domain of each variable is {1, 2, 3, 4} and the constraints are A > D, D > E, C ̸= A, C > E, C ̸= D, B ≥ A, B ̸= C, and C ̸= D + 1. Show how backtracking solves this problem. To do this, you should draw the searchtree generated to find all answers. Indicate clearly the valid schedule(s) aka solution(s).Make sure you choose a reasonable variable (and value) ordering if needed, and mention them explicitly.
Suppose that a base cuboid has three dimensions, A, B, C, with the following number of cells: |A| = 100,000, |B| = 100, and |C| = 10,000. Suppose that each dimension is evenly partitioned into 10 portions for chunking. (a) Assuming each dimension has only one level, draw the complete lattice of the cube. (b) If each cube cell stores one measure with 4 bytes, what is the total size of the computed cube if the cube is dense? (c) State the order for computing the chunks in the cube that requires the least amount of space, and compute the total amount of main memory space required for computing the 2-D planes
5.03-4. Dijkstra's Algorithm (3, part 4). Consider the network shown below, and Dijkstra’s link-state algorithm. Here, we are interested in computing the least cost path from node E to all other nodes using Dijkstra's algorithm. Using the algorithm statement used in the textbook and its visual representation, complete the "Step 3" row in the table below showing the link state algorithm’s execution by matching the table entries (i), (ii), (iii), (iv) and (v) with their values.
Develop a linked-list processing function, IsolateTargetSoloAsTail, to process a linked list as follows. ● If a target cannot be found on the given list, a new node containing the target is created and added to the list's end (made the new tail node). ► This includes the case where the given list is empty, in which the new tail node added is also the new head node. (This is so because the only node in a 1-node list is the list's head and tail node.) ● If the target appears only once on the given list, the target-matching node is moved to the list's end (made the new tail node). ► Nothing needs to be done if the target-matching node is already the tail node (of the given list). ● If the target appears multiple times on the given list, the first target-matching node is moved to the list's end (made the new tail node), and all other target-matching nodes are to be deleted from the list. ► Note that although the target-matching node to be…
Consider the reference string: 0,6,5,1,4,5,0,5,3,6,5,5,2,3,2 Use the algorithms below with 3 frames and fill the table for each algorithm (including either the page fault (F) or Hit (H) in the last row). Please note that all the frames are initially empty (as indicated in the second to the left most column below) which will cause a page fault. Copy and fill the table below for each algorithm First In First Out (FIFO) Least Recently Used (LRU) Second Chance algorithm (extension of FIFO) RS 0 6 5 1 4 5 0 5 3 6 5 5 2 3 2 Total faults Frames F/H
4) Given that a queue is being represented by the following circular representation in an array (front is currently 4 and back is currently 7): array component: 0 1 2 4 5 6 7 8 | | | | 37 | 41 | 12 | 34 | | a) Show what this representation would like after the following sequence of operations are performed: deq(q, i); deq(q, j); enq(q, 81); enq(q, 72); enq(q, 38); deq(q, k); (indicate the current position of front and back for each operation) b) What is an advantage of this implementation of a queue? c) What is a disadvantage of this implementation of a queue?