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

Explain lru approximation page replacement in detail, LRU approximation pag...

LRU approximation page replacement In this we utilize the reference bit associated with the page entry to choose a page to be removed. The various algorithms used for the imp

What is process control block, What is process control block? Every pro...

What is process control block? Every process is represented in the OS by a process control block. It has many pieces of information associated with an exact process.

Case studies, Did Abhinav agree to the initial timeline requested by Rebecc...

Did Abhinav agree to the initial timeline requested by Rebecca

How several bits are there in the logical address, Q. Regard as a logical a...

Q. Regard as a logical address space of eight pages of 1024 words every mapped onto a physical memory of 32 frames. a. How several bits are there in the logical address? b. H

Explain variable partitioning in memory management, VARIABLE PARTITIONING ...

VARIABLE PARTITIONING We can differ the partitions and change the location according to the size of the process.   50k 40k

Scheduler that select process from secondary storage device, A scheduler th...

A scheduler that selects processes from secondary storage device is known as                    Medium term scheduler is a scheduler that selects processes from secondary stor

Define lru page replacement policy, Define ‘LRU’ page replacement policy ...

Define ‘LRU’ page replacement policy LRU is Least Recently Used page replacement policy.

Essential properties of operating system, Essential Properties of Operating...

Essential Properties of Operating System 1. Batch: Jobs with similar needs are batched together and run through the computer as a group by an operator or automatic job sequen

List post-installation procedures that need to be performed, Problem: (...

Problem: (a) Based on your experience in setting up Windows 2003 Server operating system, briefly describe the twelve different steps in which the installation is conducted du

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