Implementation of modern memory management system , Operating System

Assignment Help:

Central to implementation of a modern memory management system is the page replacement algorithm. Modern virtual memory systems break memory up into pages and map (via a page table) only the pages needed, or a maximum number of pages that is constrained by system load, into the address space of the process. The page replacement algorithm is used to decide which page/s of memory to evict when different pages of memory are needed.

Using the simulators provided you will develop an understanding of the algorithms involved and perform a comparison of the efficiency of these algorithms.

2. The Simulators

The speci?cations of the simulators are as follows:

  • Only a single process run is simulated, so all the available physical memory constitutes the resident set for this process. This represents ?xed allocation, local scope policy for the resident sets.
  • The physical memory size (in frames) is an input parameter to the program. This should be less than the number of virtual pages, so some of the process pages will not ?t into physical memory.
  • The virtual address is 16-bit long. The page is addressed by the high-order 8 bits, and the offset within the page by the low-order 8 bits, so there are 256 virtual pages, each capable of holding 256 bytes.

The following data structures are provided:

  • A linear page table, which maps the virtual page number to a physical frame number. Each page table entry contains the physical frame number, and a valid bit. Other control bits or items should be added to facilitate implementation of the chosen page replacement strategy.
  • A free list, which is a list of all frames in physical memory available for allocation to the process. Initially all available frames belong to this list.
  • A resident set, which is a list of physical frames allocated to the process. Initially  this list is empty.

Initially all available frames are free, and can be allocated to the process on demand. When the free list runs out of frames, one of the frames in the resident set must be freed for the incoming page. The choice of the victim page is governed by the replacement policy.

The execution of the process is simulated by the pager program which reads virtual addresses from the input ?le, and allocates new frames to the process as required.

3 Simulator Algorithms

Three simulators (that share a common codebase) have been provided. They implement the following algorithms:

  • FIFO
  • LRU
  • Optimal

You should research each of these algorithms and develop an understanding of how these algorithms work. You do not need to understand the code beyond the level of how to run the simulators.

4 Algorithm Comparison

Four input ?les have been provided that simulate different process workloads. You should use these as input to the simulators, varying the memory size to determine which is the most ef?cient algorithm for each input, and which is the most ef?cient overall. Plotting available memory versus page fault rate will help you in this task. A spreadsheet has also been provided to assist you in making these plots.

You should after performing these experiments be able to make a recommendation about which algorithm is best for use in a real system.

5 Deliverable and Marking Guide

You are required to write a report that includes the following information, with the marks available are indicated on the right hand side:

  • Introduction to the report
  • Description of "FIFO"
  • Description of "LRU"
  • Description of "Optimal"
  • Description of experiments performed, this should be an overview of the techniques used, the results will pin this down.
  • Presentation of results for input ?le 1, (this could just be a graph), and a ranking of the three algorithms performance.
  • Presentation of results for input ?le 2 and a ranking of the three algorithms performance.
  • Presentation of results for input ?le 3 and a ranking of the three algorithms performance.
  • Presentation of results for input ?le 4 and a ranking of the three algorithms performance.
  • Conclusions and recommendation of algorithm, this should be supported by your data.

Related Discussions:- Implementation of modern memory management system

Main advantage of the layered approach to system design, What is the main a...

What is the main advantage of the layered approach to system design? As in all cases of modular design, designing an operating system in a modular way has several benefits. Th

Explain busy waiting semaphores, Explain Busy Waiting Semaphores Weak, ...

Explain Busy Waiting Semaphores Weak, Busy-wait Semaphores a) The simplest way to implement semaphores. b) Useful while critical sections last for a short time, or we com

Page faults, Assume there are only 4 page frames in the physical memory, fo...

Assume there are only 4 page frames in the physical memory, for the following reference string: 1, 2, 3, 4, 5, 3, 4, 1, 6, 7, 8, 7, 8, 9, 7, 8, 9, 5, 4, 5, 4, 2, 8. a) What i

Explain the performance of demand paging, Performance of demand paging ...

Performance of demand paging Demand paging can have an important effect on the performance of a computer system. As long as there are no page faults, the effective access time

Explain logical file system architecture, Logical File System Responsi...

Logical File System Responsible for providing the before discussed interface to the user including: File access. Directory operations. Security and protection.

Explain process termination - operating system, Process termination A p...

Process termination A process terminates when it finishes implementing its final statement and asks the operating system to delete it by using the exit system call. At that tim

Determine scheduling policy for time-shared operating system, Determine a s...

Determine a scheduling policy that is most suitable for a time-shared operating system   Round-Robin is a scheduling policy that is most suitable for a time-shared operating s

What are placement and replacement algorithms, Placement algorithms :calcu...

Placement algorithms :calculate where in available real-memory to execute a program. Common functions are next-fit, first-fit, and best-fit. Replacement algorithms :are

Explain nonvolatile - volatile and stable storage, Q. Explain the differenc...

Q. Explain the differences in terms of cost between the three storage types nonvolatile, volatile and stable. Answer: Volatile storage refers to main as well as cache memory an

Describes responsibilities of the I/O manager, Q. Describes responsibilitie...

Q. Describes responsibilities of the I/O manager? Answer: The I/O manager is responsible for file systems and device drivers and network drivers. The I/O manager keeps follow

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd