Mark-sweep, Operating System

Assignment Help:

The objects that a program can access directly are those objects which are referenced by local vari-ables on the processor stack, or by any global/static variables that refer to objects, or by variables in CPU registers. In the context of garbage collection, these variables are called the roots. An object is indirectly accessible if it is referenced by a ?eld in some other (directly or indirectly) accessible object. An accessible object is said to be live. Conversely, an object which is not live is garbage.

Note that heap objects which are live are indirectly accessible from the roots or other heap objects. The idea of mark-sweep is relatively straightforward. We start at the roots, and recursively visit every object accessible through pointers, marking them as live. At the end of the process, every thing not marked is considered garbage and will be deleted. Notice that mark-sweep can perform lazy garbage collection, in the sense that it does not necessarily need to remove the garbage immediately.

Note thatmark-sweep does not clean upmemory which is allocated, but simply never used. Also, periodically we have to visit all objects recursively, starting from the roots. For a large program, this will be slow. This is a problem with the traditional mark-sweep algorithm.


Related Discussions:- Mark-sweep

Relationship among the capabilities of domain level j and i, Q. In a ring-...

Q. In a ring-protection system the level 0 has the greatest access to objects and level n (greater than zero) has fewer access rights. The access rights of a program at a partic

Explain about system software, An operating system act as an intermediary b...

An operating system act as an intermediary between user of a computer and computer hardware. The objective of an operating system is to provide an environment in that a user can ex

Explain segmentation hardware?, Explain segmentation hardware? We defin...

Explain segmentation hardware? We define an completion to map two-dimensional user-defined addresses into one-dimensional physical addresses. This mapping is affected by means

What is segmentation?, SEGMENTATION In a memory management system that ...

SEGMENTATION In a memory management system that is properly a programmer views a program to be collection of program components called as segments . Every segment is a logical

Unix , A friend has promised to log in at a particular time. However, he ne...

A friend has promised to log in at a particular time. However, he needs to be contacted as soon as he logs in. The shell script checks after every minute whether he has logged in o

Briefly describe the producer-consumer problem, Question: a) Each proc...

Question: a) Each process is represented in the operating system by a process control block (PCB). The PCB contains many pieces of information associated with a specific proce

What the different paging techniques, The different paging techniques are ...

The different paging techniques are 1. Multilevel paging or hierarchical paging method: In definite cases the page table may consist up to 1 million entries. This would be

Explain the concept of mutual exclusion, Question 1: (a) Discuss about...

Question 1: (a) Discuss about the evolution of operating systems from mainframe batch systems to mainframe time sharing systems. (b) Explain your understanding of the "sus

Can we call trap as an interrupt??, is there any difference between the tra...

is there any difference between the trap and interrupt??

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