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

What are interrupts?, What are interrupts? Interrupts are in some way...

What are interrupts? Interrupts are in some ways the mainly "famous" system resources, ever since almost everyone who's used a computer has heard of them even if they don't k

How resolution of externally defined symbols is performed, Resolution of ex...

Resolution of externally defined symbols is carried out by    Resolution of externally defined symbols is carried out by Linker

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

Define page stealing, Define Page stealing    Page stealing is taking ...

Define Page stealing    Page stealing is taking page frames another working sets

What is file allocation?, What is File Allocation? The structure that ...

What is File Allocation? The structure that offers the FAT file system its name is the file allocation table . In order to know what this important table does, you should fir

List operations to be performed on directories, List operations to be perfo...

List operations to be performed on directories. Search for a file, delete a file, create a file, list a directory, rename a file, and traverse the file system.

What are the disadvantages of linked allocation, What are the disadvantages...

What are the disadvantages of linked allocation? The drawbacks are a. Used only for sequential access of files. b. Direct access is not supported c. Memory space neede

Peer to peer network and a client server network, Question : a) Describ...

Question : a) Describe the difference between the authentication of a user account on a peer to peer network and a client server network. b) Compare an end user account with

Networking tidbits, There is a very small amount of networking background r...

There is a very small amount of networking background required for Project 2. In Project 2, we want our computer (or our "host") to request information over the Internet from a rem

Explain multithreading operating system, Multithreading - Operating system...

Multithreading - Operating systems that permit different parts of a software program to run concurrently. Operating systems that would come into this category are: Linux UNI

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