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Group Questions Student Questions · (True or False) Segmented memory allocation of each job is divided into several segments of different size, one for each module that contains pieces that perform related functions. (Hyo Moon: 2) · (Fill in the blank.) Fill in the names of the states of the State Diagram shown below. · In the PCB, what are the five steps of the “Process Status”? (John Royal: 2) · What is a page fault? (Tamara Ann Carter: 2) o A page fault happens when a failure to find a page in memory occurs. · (True or False) The Memory Manager is only one of four “managers” that make up the operating system. (Tangela Robinson: 2) · (True or False) The nonpreemptive scheduling algorithm that handles jobs according to their arrival time is FIFO. (Tangela Robinson: 2) · (True or False) A segmented map table contains the following bits: Protection, Reference, Modified, Status, and Subroutine. · What does the processor do? (Jeremy Hall: 4) o This is the part of the machine that does the calculations and executes the programs. · What are sections of main memory called? (Nathan Horne: 4) o Page frames. · What is indefinite postponement? (Nathan Horne: 4) o A job’s execution is delayed indefinitely. · A period of time assigned to a process for execution is called __________ . (Sean Ampula: 4) o Time quantum o Quantum leap o Time warp o Quantum physics · What are the five processor states? (Kam Scott: 4)
Group Questions · What are the two general rules of thumb for selecting the “proper” time quantum? (Brian Shore, Jose Muniz, Larry Lloyd, Chuck Phillips: 2) o It should be long enough to allow 80% of the CPU cycles to run to completion. o It should be at least 100 times longer than the time required to perform a context switch. · What is a preemptive scheduling policy? (William McNair, Sean Ampula, Jeremy Hall, Nathan Horne: 4) o Interrupts the processing of a job and transfers the CPU to another job. Student Questions · What is a preemptive scheduling policy? (John Royal: 2) · The FIFO algorithm uses only the __________ bit and the __________ bit when swapping pages. (Brent Steinhaus: 2) · (Multiple Choice) One innovation that improved the performance of demand paging schemes was the concept of the __________ . (Brent Steinhaus: 2) o Working Set o Modules o Segments o Virtual Memory · What are the two general rules of thumb for selecting the “proper” time quantum? (Butch McClain: 2) o It should be long enough to allow 80% of the CPU cycles to run to completion. o It should be at least 100 times longer than the time required to perform one context switch. · Which memory allocation scheme was the first widely used scheme that removed the restriction of having the entire job in memory from the beginning to the end of its processing? (Myongsin Masek: 2) o Paged memory allocation. o Demand paging memory allocation. o Segmented memory allocation. o Segmented/ demand paged memory allocation. · (Multiple Choice) Which of the following algorithms are not preemptive? (Myongsin Masek: 2) o Shortest Remaining Time (SRT) o Round Robin o Variable time quantum per queue o Shortest Job Next (SJN) · (Multiple Choice) What is one of the most common nonpreemptive scheduling algorithms in a batch system? (Myongsin Masek: 2) o FCFS o SJN o Priority Scheduling o Round Robin · What is the processor manager? (Tamara Ann Carter: 2) o The processor manager is a composite of two submanagers, the job scheduler and the process scheduler. It decides how to allocate the CPU, monitors whether it is executing a process or waiting, and controls the job entry to ensure balanced use of resources. · Write the two general rules of thumb for selecting the “proper” time quantum. (Jose Muniz: 2) o It should be long enough to allow 80% of the CPU cycles to run to completion. o It should be at least 100 times longer than the time required to perform one context switch. · What are the low, middle, and high level schedulers? (Larry Lloyd: 2) o Low: Process scheduler o High: Job scheduler o Middle: Job suspension scheduler (see near the bottom of page 78). · (Multiple Choice) Which memory allocation scheme is based on the concept of dividing each incoming job into pages of equal size? (Chuck Phillips: 2) o Segmented o Demand o Paged o FIFO · (Select the Right Choice). It contains the basic information about a job including what it is, where it is going, how much of its processing has been completed, where it is stored, and how much it has spent in using resources. (Chuck Phillips:2) o Process Control Block (PCB) o Memory Control Block (MCB) o Low-Level Scheduler o Middle-Level Scheduler · Classify the following scheduling policies as preemptive or nonpreemptive. (Michele O’Donnell: 2) o First Come First Served o Round Robin o Shortest Job Next o Shortest Remaining Time · Name the four memory management schemes. (Michele O’Donnell: 2) · Draw the state diagram for process management. (Michele O’Donnell: 2) · The capability of moving pages at will between two storage areas (main memory and secondary storage) is called: (Chris Barrett: 2) o Overlays o Virtual Memory o Thrashing o Page Fault · Which configuration would be the best for a fast moving, missing critical work area such as an airport terminal? (Augustus Lamar Hill: 4) o Interactive System o Real-time System · What is first-fit memory allocation? (Jeremy Hall: 4) o A main memory allocation scheme that searches from the beginning of the free block list and selects for allocation the first block of memory large enough to fulfill the request. · When there is an excessive amount of page swapping back and forth between main memory and secondary storage, the operation becomes inefficient. This is a phenomenon called _________ . (Sean Ampula: 4) o Thrashing o Head banging o Sloshing o Indefinite transition loop · What is a working set? (William McNair: 4) o A set of pages residing in memory that can be accessed directly without incurring a page fault. · What is preemptive scheduling policy? (William McNair: 4) o Interrupts the processing of a job and transfers the CPU to another job. · What information is kept in the process control block? (Conrad Dailey: 4) · What is a multiprogramming environment? (Kenny Blackburn: 4) o Many users, many jobs, fair manner of allocation · Job Scheduling versus Process Scheduling. Scheduler handles two jobs: loading and execution. Each job utilized by the job scheduler. Processor determines when to do the job. (Kenny Blackburn: 4) · Name 2 nonpreemptive scheduling algorithms and 2 preemptive scheduling algorithms. (Tom Hobgood: 4)
· What is the major advantage of paging schemes? (Kam Scott: 4) o Memory is used more efficiently. · What are the advantages of virtual memory? (Kam Scott: 4) · As a general rule, a time quantum should be: (Rudolph Jones: 4) o At least 80 times longer than the time required to perform one context switch. o Long enough to allow 80% of the CPU cycles to run to completion. o At least 100 times longer than time required to perform one context switch. o Long enough to allow 100% of CPU cycles to run to completion. · In a nonpreemptive scheduling policy a job will be interrupted when: (Rudolph Jones: 4) o A job with higher policy arrives at READY. o There is a SJN (Shorter job next) in the queue. o It issues its own I/O request. o The job is finished. · What is the purpose of a referenced bit? (Brian Rappach: 4) · What does the PCB contain? (Brian Rappach: 4) · What is a subroutine? (Josh Blaylock: 4) o Also called a “subprogram”, this is a segment of a program that can perform a specific function. Subroutines can reduce programming time when a specific function is required at more than one point in the program. · (True or False) A page is a variable size section of a user’s job that contains a local grouping of code. (Josh Blaylock: 4) · What preemptive process scheduling algorithm that is very to use in an interactive system. (Ian Fassnacht.) · What does virtual memory do? (Ian Fassnache)
Group Questions · Draw a timeline for each algorithm (FCFS and SJN) and give a turnaround time for each: (Marshall Baker, mark Jackson, Conrad Dailey: 4)
Student Questions · What are the major factors that delayed the advancements in Memory Allocation Scheme evolution? (Augustus Lamar Hill: 4) o Hardware limitations, basic coding overhead, and hardware cost of producing advanced chips. · A job has 875 lines and each page has 200 lines. Determine the page number and displacement of line 640. (Rudolph Jones: 4)
Group Questions · In what memory scheme is the term “working set” used, and how does it improve performance? (Myongsin Masek, Butch McClain, Tangela Rovinson, Tamara Ann Carter: 2) o It is used in demand paging schemes. The working set is the set of pages residing in memory that can be accessed directly without incurring a page fault. · What is the advantage of FCFS? (Marshall Baker, Mark Jackson, Conrad Dailey: 4) · (Mark all that are true.) In a nonpreemptive scheduling policy, a job will be interrupted when: (Tom, Rudy, Kam, Brian, Kenny: 4) o A job with a higher priority arrives at the Ready queue. o There is a SJN in the queue. o It issues its own I/O request. o The job is finished. · What nonpreemptive algorithm gives preferential treatment to important jobs? (Ian Fassnacht, Josh Blaylock: 4) ·
Student Questions · In what memory scheme is the term “working set” used, and how does it improve performance? (Butch McClain: 2) o It is used in demand paging schemes. The working set is the set of pages residing in memory that can be accessed directly without incurring a page fault. · What is the primary advantage of storing programs in noncontiguous locations? (Jose Muniz: 2) o Main memory is used more efficiently because an empty page frame can be used by any page of any job. · Segmented memory allocation is based on the common practice of programmers to structure their code into modules. Why is this? (Larry Lloyd: 2) o It is more efficient to segment the program from these modules. · In rare cases, with a first-in first-out page replacement policy, increasing the size of main memory results in a higher number of page interrupts. What is the cause of this higher failure rate? (Brian Shore: 2) o This is known as the FIFO anomaly or Belady’s anomaly. Because of this anomaly, there is no guarantee that increasing memory will result in better performance. · What is the high-level scheduler? What is its purpose? (Brian Shore: 2) o Each job (or program) passes through a hierarchy of managers. Since the first one it encounters is the job scheduler, this manager is known as the high-level scheduler. o The job scheduler is only concerned with selecting jobs from a queue of incoming jobs and places them in the process queue based on each job’s characteristics. · What are two ways to reduce thrashing? (Michele O’Donnell: 2) · What is the difference between job scheduling and process scheduling? (Michele O’Donnell: 2) ·
Main memory is 2 pages. Compare
FIFO and LRU for the following order: · Given that main memory is composed of 2 page frames for public use and that a program requests pages in the following order: A B C B A C B A B C. using LRU Algorithm, do a page trace analysis indicating page faults with (*). Then compute success and failure ratios and rates. (Tom Hobgood: 4)
Failure Ratio: 8/10, Failure Rate: 80% Success Ratio: 2/10, Success Rate: 20% ·
Group Questions Student Questions
Group Questions Student Questions |
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