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

Roles of operating systems, Describe Three major roles of operating systems...

Describe Three major roles of operating systems in business computer systems

Calculate the maximum file size , A UNIX file system has 1-KB blocks and 4-...

A UNIX file system has 1-KB blocks and 4-byte disk addresses. What is the maximum file size if i-nodes contains 10 direct entries, and one single, double, and triple indirect entry

Bankers algorithm, p0A B C D A B C D A B C D 2 0 12 2012 1000 1354 0632 ...

p0A B C D A B C D A B C D 2 0 12 2012 1000 1354 0632 0014

Transferring files from windows to unix, Transferring files from Windows to...

Transferring files from Windows to Unix Be very careful transferring files from Windows to Unix. If you do transfer a file from Windows to Unix open the file, in Unix, using vi

What are the advantages and disadvantages of multithreading, What are the a...

What are the advantages and disadvantages of multithreading?  Advantages : Since by multithreading multiple executions are carried out in the same process environment t

SYSTEM PROGRAMMING, advantages and disadvantages of monolithic and layered ...

advantages and disadvantages of monolithic and layered approach

Interprocess communication, Now we consider the following questions: how ca...

Now we consider the following questions: how can the parent process communicate with its child? Or how can children processes communicate with other children? The exact answer depe

What are the issues in designing a network-scalability, Scalability : ...

Scalability : Scalability is the competence of the system to adapt to increased service load. A scalable system will respond more gracefully to increased load than a non-sc

What is the information associated with an open file, What is the informati...

What is the information associated with an open file? Various pieces of information are associated with  an open file which may be: File pointer Disk location of th

Major advantage of the layered approach to system design, Q. What is the ma...

Q. What is the major advantage of the layered approach to system design? What are the de-merits of using the layered approach? Answer: As in all cases of modular design as well

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