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

First-in-first-out (fifo), FIFO is named as 'named pipes'. FIFO (first-in-...

FIFO is named as 'named pipes'. FIFO (first-in-first-out) is a special file which is laid to be data transient. Once data is load from named pipe, it cannot be load again. Also, da

Explain chaining to handle collision, Explain Chaining to Handle Collision ...

Explain Chaining to Handle Collision Chaining:  One easy scheme is to chain all collisions in lists attached to the suitable slot. This permits an unlimited number of collision

PSEUDO CODE FOR PROGRAM, THE PROGRAM WILL CHOOSE TWO RANDOM NUMBERS,THEN PR...

THE PROGRAM WILL CHOOSE TWO RANDOM NUMBERS,THEN PRINT THEM OUT AS AN ADDITION PROBLEM.THE PROGRAM WILL THEN ASK THE USERTO ENTER THE CORRECT ANSWER.IF THE ANSWER IS CORRECT,THE PRO

Illustrate the function of loader, Q. Illustrate the function of Loader? ...

Q. Illustrate the function of Loader? A loader is a routine which loads an object program and prepares it for execution. There are many loading schemes: relocating, absolute an

Operating systems structures, with the aid of diagrams describe the followi...

with the aid of diagrams describe the following OS structure monolithic,layered and client server.

Explain system-wide open-file and per-process open-file, Explain system-wid...

Explain system-wide open-file and per-process open-file The system-wide open-file table have a copy of the FCB of each open file, as well as other information. The per-pr

Define rotational latency and disk bandwidth, Define rotational latency and...

Define rotational latency and disk bandwidth. Rotational latency is the additional time waiting for the disk to rotate the wanted sector to the disk head. The disk bandwidth is

State the advantage of multiprocessor system, State the advantage of multip...

State the advantage of multiprocessor system? The advantages of multiprocessor system are:- a)      Enhanced throughput. b)      Economy of scale. c)       Enhanced re

Discuss distributed file system caching, Problem: (a) Discuss Distribut...

Problem: (a) Discuss Distributed File System Caching. (Your discussion should include the goal and architecture of distributed file system caching and the various possible c

Sector sparing, What is sector sparing is proper definition

What is sector sparing is proper definition

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