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

How many cubic feet of storage space would require, Q. Presume that we agr...

Q. Presume that we agree that 1 kilobyte is 1,024 bytes 1 megabyte is 1,0242 bytes and 1 gigabyte is 1,0243 bytes. This progression carries on through terabytes, petabytes, and ex

Identifying parallelism, Identifying parallelism A formal way to identi...

Identifying parallelism A formal way to identify parallelism in an activity is to draw a task dependence graph in a directed graph in which each vertex represents a task to

Define approaches that require knowledge of the system state, Define approa...

Define approaches that require knowledge of the system state?  Answer: Deadlock detection, Deadlock prevention, Deadlock Avoidance.

Explain the overlay structured program, Overlay structured program: A p...

Overlay structured program: A program consisting of overlays is referred as overlay structured program in which an overlay is a part of program which has similar load origin as

Explain rehashing to handle collision, Explain Rehashing to Handle Collisio...

Explain Rehashing to Handle Collision Rehashing:  Re-hashing schemes make use of a second hashing operation while there is a collision. If there is an additional collision, we

Principles of informtiona tecnologu, i need to complete project on lan arch...

i need to complete project on lan architceture RAIDs etc

FUNDAMENTAL OF OS, WHAT IS OPERATING SYSTEM ?ENLIST AND EXPLAIN BASIC SERVI...

WHAT IS OPERATING SYSTEM ?ENLIST AND EXPLAIN BASIC SERVICES PROVIDE BY OS

Prepare a short note on the standard linux file system, Problem: a) Pre...

Problem: a) Prepare a short note on the standard Linux File System. b) Prepare a short note on the RPM Package Management Tool. c) Briefly explain the two types of login

Explain kernel activity for ults, KERNEL ACTIVITY FOR ULTS: The kernel...

KERNEL ACTIVITY FOR ULTS: The kernel isn't aware of thread activity but it is still managing process activity. When a thread compose a system call the whole process will be bl

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