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

Utility programs, Utility Programs: those programs which are not the essen...

Utility Programs: those programs which are not the essential part of operating system. But they provide different utilities / features to the users e.g. MS-DOS : Fdisk, FORMAT, AT

What is critical section problem, What is critical section problem? Con...

What is critical section problem? Consider a system consists of 'n' processes. Every process has segment of code called a critical section, in which the process might be changi

Explain the per thread scoping, Explain the Per Thread Scoping Thread-l...

Explain the Per Thread Scoping Thread-level programming introduces new twists for application-level variable scoping. Threads are commonly used in one of two ways. To ex

Managing outside communication, Problem: Managing Outside Communication...

Problem: Managing Outside Communication. a. What is the principal action we use when communicating through a web browser? b. Give an example of how to preaddress an email

Semantics for execution of rpcs, Q. Presume that a distributed system is su...

Q. Presume that a distributed system is susceptible to server failure. What mechanisms would be needed to guarantee the exactly once semantics for execution of RPCs? Ans

What do you understand by “line balancing”? What happens if , What do you u...

What do you understand by “line balancing”? What happens if balance doesn’t exist?

Explain and differentiate programmed and interrupt i/o, Question 1 Explain...

Question 1 Explain the structure of operating system in detail Question 2 Explain the following scheduling algorithm                                     1) First come Firs

Write a linux script to add name in class list, For this exercise I wanted ...

For this exercise I wanted to give you some real-world examples of useful bash scripts. Therefore, you will write a couple of scripts that I actually use in my teaching to automate

Parent and child process communicate in unix, Parent and Child process comm...

Parent and Child process communicate in unix A child and parent can interact through any of the normal  inter-process communication schemes (pipes, message queues, sockets, s

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