Describe two segment-replacement algorithms, Operating System

Assignment Help:

Q. Segmentation is alike to paging but uses variable-sized "pages". Describe two segment-replacement algorithms based on FIFO and LRU page replacement schemes. Remember that since segments aren't the same size the segment that is chosen to be replaced mayn't be big enough to leave enough consecutive locations for the needed segment. Consider tactics for systems where segments cannot be relocated and those for systems where they can.

Answer:

a. FIFO. Find the first segment large sufficient to accommodate the incoming segment. If relocation isn't possible and no one segment is large enough select a combination of segments whose memories are contiguous which are closest to the first of the list and which are able to accommodate the new segment. If relocation is probable rearrange the memory so that the first N segments large sufficient for the incoming segment are contiguous in memory. Add any leftover space to the free-space list in both cases.

b. LRU. Select the segment that hasn't been used for the longest period of time and that is large enough adding any leftover space to the free space list. If no one segment is large sufficient select a combination of the oldest segments that are contiguous in memory (if relocation isn't available) as well as that are large enough.

If relocation is obtainable rearrange the oldest N segments to be contiguous in memory as well as replace those with the new segment.


Related Discussions:- Describe two segment-replacement algorithms

Advanced synchronization, Synchronization serves two purposes: 1) to ensure...

Synchronization serves two purposes: 1) to ensure safety for updates on shared data (e.g. to avoid races conditions), and 2) to coordinate and order actions taken by threads (e.g.

Draw and r chart and an x-bar chart, Thermostats are subjected to rigorous ...

Thermostats are subjected to rigorous testing before they are shipped to air conditioning technicians around the world. Results from the last five samples are shown in the table. D

Inventory differences, What makes a Just-in-Time inventory system differ fr...

What makes a Just-in-Time inventory system differ from a traditional inventory system?

Describe paging algorithm needs a reference bit, Q. Suppose that you want ...

Q. Suppose that you want to utilize a paging algorithm that requires a reference bit (such as second-chance replacement or working-set model) however the hardware does not provide

Pthreads, A thread is defined as an independent stream of instructions that...

A thread is defined as an independent stream of instructions that can be scheduled to run as such by the operating system. Each program contains a number of threads which can be ru

Explain briefly the working of semaphore with example ?, Explain briefly th...

Explain briefly the working of semaphore with example ? The E.W. Dijkstra (1965) abstracted the key idea of mutual exclusion in his concepts of semaphores. Definition A s

Paging, ___paging fecthces a page only when needed

___paging fecthces a page only when needed

Linux operation system, wat are the commands used for creating the file hie...

wat are the commands used for creating the file hierarchy

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