Chapter Questions 6 2, 3, 8, 9, 12. 8 1, 13(a) 9 10, 12, 13, 15 11 1 SAMPLE QUESTIONS (including some questions from the Ph.D. Qualifying exam in OS): • Employing semaphores, Solve the reader/writer problem giving the writer priority. • Describe the deadlock detection algorithm found on pages 266-268. • Considering the basic function of a page table, for example: the need to locate, replace, or swap pages to/from secondary storage; memory protection and sharing, explain what the fields of a page-table would be and the rational for each field. • Given a system that uses the banker’s algorithm for avoiding deadlock and the resource state shown below, explain why it is a safe or unsafe state. Assume that the total number of each system resource is, where and R i means the amount of resource i.

Operating Systems • Let us do. • The operating system is a resource manager that provides an. – scheduling a serially-reusable resource among several users. The Deadlock Problem. Permanent blocking of a set of processes that either compete for system resources. Tand Fare serially reusable resources.

Preemptible resources. Non-preemptible resources serially reusable resource Paging virtual memory working-set Priority preemption memory fragmentation quantum preemption Thrashing Page Frame page fault • Discuss at least 4 weaknesses in the Banker’s Algorithm. • Compare and contrast what is meant by a process’ location space and its name space. • A memory management system must consider a number of problems, discuss code/data, fragmentation, memory partitioning, protection, and swapping. • Explain how a paging system works, be certain to include faults, thrashing, pages, frames, swapping, page replacement strategies, address translation, and anomalies. Garmin Gpsmap 76 Driver Download. • Explain the mapping of a virtual address to a real address under a paging system, include faults, pages, page frames, swapping, page replacement (be sure you are clear, and use diagrams if necessary.) • Discuss deadlock; what is it. Provide an illustration, explain the necessary conditions for deadlock, and name the three basic approaches to handling deadlock.

• Discuss/explain scheduling methodologies; include non-preemptive versus preemptive, FCFS, SPN, RR, and multilevel feedback queues. • There are three basic issues in defining a paging policy: when to fetch a page, when to remove/replace a page, and where to place pages. Discuss one aspect of each issue. • Consider the following experiment and explain the observations. A program is run by itself on a paging machine. The program begins execution with its first procedure page. As it runs, the pages it needs are demand paged into available page frames.

The number of available page frames is much much larger than the number of pages in the program. Arturia Oberheim Sem V Mac Osx Downloads on this page. Also, there is a dial external to the computer that allows a person to set the maximum number of page frames the program may use. Initially, the dial is set to 2 frames and the program is run to completion. The dial is then set at 3 frames and again the program is run to completion.

This process is continued until the dial is eventually set to the number of available pages in real storage, and the program is run for the last time. For each run, the execution time of the program is recorded. Observations: As the dial is changed from 2, to 3, to 4, the execution time improves dramatically. From 4, 5, to 6, the execution time still improved each time, but less dramatically. With the setting of 7 and higher the execution time is essentially constant.

Assume a disk with 200 tracks and that the disk request queue has random requests in it. The requested tracks, in the order received are: 55, 58, 39, 18, 90, 160, 150, 38, and 184. Assuming that the disk head is a track 100, and is moving toward track 200, show the sequence that the requests will be serviced and the total track sequence traversed for each of the following scheduling policies: FCFS, SSTF, and SCAN. Exam) Semaphores: Using semaphores, implement a writer's priority solution to the readers/writes problem. Exam) Deadlock: A system that uses the Banker's Algorithm deadlock avoidance has five (5) processes (1, 2, 3, 4, and 5) and four (4) types of resources (A, B, C, and D). There are multiple resources of each type. Is the following state safe or not?

If it is, show how the processes can complete. If not, show how they can deadlock.